# Optimising hot water schedule



## Glitch (1 Oct 2022)

Started a new thread to avoid hijacking the meter reading one.



Glitch said:


> After many years of resisting, waiting for compatibility between suppliers, I finally had smart meters installed.
> 
> Set up with half hourly readings and downloadable data I could spend hours analysing gas and electricity usage. Occasionally I have a look.
> *I'm trying to optimise the hot water heating/storage. 3 bursts a day, or just one? I'm thinking it shouldn't really make much difference.*


@johna.clements replied:



> When the hot water is cooling down it is heating the house. If you are out do you need hot water and heating to the house. I would heat the water when you need a lot of hot water. You could also time your use of the hot water so that you benefit from the waste heat.



The boiler is fairly new and we did get a new, well insulated hot water tank at the same time. Relatively short pipe runs to the bathroom,
Long ones to kitchen, utility room and cloakroom which must lose heat. Exposed hot water pipework is not insulated.
Both retired so usually someone in during the day.

Currently it's hard to predict our use on a day by day basis. Me and the missus tend to alternate daily routines around dog walking but maybe we need to get into more of a fixed routine. 
Start showering at the same time perhaps 

Avoiding use of the central heating at the moment and will use woodburner to heat downstairs.

I have spotted a strange anomaly in my gas usage. Nothing in the heating or hot water schedule to account for the use after midnight and before 08:00.
Unless that is, the temp drops to under 10.5c which is highly unlikely. Even in these chillier mornings the hall stat is above the 16.5c I had set during the summer.




I've just removed the 18:00 - 18:30 schedule. but the use around 02:30 is a mystery


----------



## Pedronicus (1 Oct 2022)

I certainly wouldn't have a program that allows the system to fire up overnight. For morning hot water use set the HW side to come on 1/2 an hour before the heating for a period of 2 hours And then able to run from, say, 1530 to 2100.

You don't say what controls you have but if app based they can be too clever for their own good. Also don't know what system you have installed but it looks like there is a top-up taking place overnight. More info needed for detailed advice.


----------



## Glitch (1 Oct 2022)

I use Nest. 
I can see in the App usage history that there is no call for heat from the thermostat.





I think the idea of heating the hot water before the room heating is a good one. Better to heat one circuit at a time rather than two.
Interesting suggestion about 15:30 - 21:00 I guess it shouldn't need much to keep the heat topped up.

Only other gas appliances are the burners on the cooker.

The mystery use could only be hot water. 
I'm ruling out leaks.
I could ask our heating engineer if he has any ideas.


----------



## johna.clements (1 Oct 2022)

It is strange that the hot water is heating at 200 in the morning. Maybe Rumpelstiltskin is running a laundry at night.


----------



## Glitch (1 Oct 2022)

Schedules are very simple


----------



## Spectric (1 Oct 2022)

Everything will be a balance between the heat losses from the system and periods of usage. There is no point in heating the hot water too late in the day if the next period of high usage is the next day. I have an OSO cylinder that is well insulated and an unvented system using a Worcester boiler, the hot water comes on around 7:00 Am for thirty minutes and then around 4:00 Pm for thirty minutes and that is that, if we need extra then there is the overide on the controller. 



Glitch said:


> Exposed hot water pipework is not insulated.


That is not good, the hot water supply pipework should be well insulated to prevent heat losses, also to protect from freezing. 

The overall efficiency of a system is not down to individual components but the complete system design so to get the best efficiency, it cannot be achieved by just replacing the odd component. The pump / circulator is another area where savings can be made, ensure the pump is fitted into the return pipework to the boiler which reduces it's running temperature and use a smart Grunfoss pump like 









ALPHA1 15-50/60 130


ALPHA1 is a circulator pump designed for heating systems. The pump has integrated differential-pressure control as well as constant-curve mode. The ideal choice for basic functionality needs.




product-selection.grundfos.com





This pump uses less energy because it matches it's flow to the current demand, but you cannot use pressure operated bypass valves in the system.


----------



## Glitch (1 Oct 2022)

Only had these overnight anomalies 5 nights in the past week and nothing before then.

I have a vented system with an insulated copper cylinder. I will insulate the pipes.

The pump put in when the boiler was replaced was not up to the job and got upgraded. Still not as good as the old one.


----------



## Pedronicus (1 Oct 2022)

If you have the Gen 3 Nest then it can also control the hot water. If so then check that the HW is not set for 24hr operation. If just a standard timeswitch to control the HW then check to see if it is not set to Constant or 24 Hr. If so then set it to a timed programme to suit your needs.


----------



## Glitch (1 Oct 2022)

Pedronicus said:


> If you have the Gen 3 Nest then it can also control the hot water. If so then check that the HW is not set for 24hr operation. If just a standard timeswitch to control the HW then check to see if it is not set to Constant or 24 Hr. If so then set it to a timed programme to suit your needs.


HW only comes on twice a day (from today) previously three times. Definitely not set to 24hrs.


----------



## selectortone (1 Oct 2022)

Many here probably know this, but it's worth mentioning: Turning down the temperature control on the boiler and the temperature sensor on the hot water tank has made a significant improvement to my gas consumption. For years - since I had a new boiler installed - it was scalding hot and having a shower or washing up required mixing in lots of cold water. I had a light bulb moment when I was warning my daughter about my granddaughter using the shower.


----------



## johna.clements (1 Oct 2022)

selectortone said:


> Many here probably know this, but it's worth mentioning: Turning down the temperature control on the boiler and the temperature sensor on the hot water tank has made a significant improvement to my gas consumption. For years - since I had a new boiler installed - it was scalding hot and having a shower or washing up required mixing in lots of cold water. I had a light bulb moment when I was warning my daughter about my granddaughter using the shower.


As long as you do not turn it down too low so legionella bacteria grow.


----------



## Glitch (1 Oct 2022)

60-65c is the recommended temperature


----------



## Mal-110 (2 Oct 2022)

We have a similar system to yours. On checking gas usage on the suppliers app we found 13p or 14p’s worth of gas used every other morning whilst we were away. The hot water and central heating were all off. Contacted the supplier and it does not happen now. No explanation was given but we presume they have re-calibrated the new smart meter. 
It may well be a good idea to turn everything off for a day to check that the meter is reading properly.


----------



## Pedronicus (2 Oct 2022)

Yet another reason not to have a Smart Meter!


----------



## Glitch (2 Oct 2022)

Mal-110 said:


> We have a similar system to yours. On checking gas usage on the suppliers app we found 13p or 14p’s worth of gas used every other morning whilst we were away. The hot water and central heating were all off. Contacted the supplier and it does not happen now. No explanation was given but we presume they have re-calibrated the new smart meter.
> It may well be a good idea to turn everything off for a day to check that the meter is reading properly.


I'm going to change the schedule again on the back of advice and I'll keep an eye on it.
I'm with London Power (Octopus Energy). I'll take it up with them if there is further unexplained consumption.


----------



## Glitch (2 Oct 2022)

Pedronicus said:


> Yet another reason not to have a Smart Meter!



At least it is telling me there's a potential issue!

Unless you stay up all night doing meter readings how would you know you have unexplained consumption with your dumb meter?


----------



## Spectric (2 Oct 2022)

Mal-110 said:


> No explanation was given but we presume they have re-calibrated the new smart meter.


A smart meter gives the supplier complete control over your energy cost, what it determines as usage can also be changed but a non smart meter is a simple device that has been in use for decades with a proven track record of reliability and honesty.


----------



## NormanB (2 Oct 2022)

Pedronicus said:


> I certainly wouldn't have a program that allows the system to fire up overnight. For morning hot water use set the HW side to come on 1/2 an hour before the heating for a period of 2 hours And then able to run from, say, 1530 to 2100.
> 
> You don't say what controls you have but if app based they can be too clever for their own good. Also don't know what system you have installed but it looks like there is a top-up taking place overnight. More info needed for detailed advice.


First is your boiler in the garage?

Second in broad terms (all other things being equal) the hotter you drive your water temperature up the greater the rate of heat loss. You need to match your DHW schedule to your useage. We have a 210 litre DHW cylinder and raise the temperature every other day to 50 deg C, once a week to 60 (risk reduction legionella).


----------



## Glitch (2 Oct 2022)

Spectric said:


> A smart meter gives the supplier complete control over your energy cost, what it determines as usage can also be changed but a non smart meter is a simple device that has been in use for decades with a proven track record of reliability and honesty.



Sounds like conspiracy theory stuff to me. Presumably the suppliers are acting as a cartel and all in on it?

Perhaps you can give some examples of suppliers manipulating usage.


----------



## Glitch (2 Oct 2022)

NormanB said:


> First is your boiler in the garage?
> 
> Second in broad terms (all other things being equal) the hotter you drive your water temperature up the greater the rate of heat loss. You need to match your DHW schedule to your useage. We have a 210 litre DHW cylinder and raise the temperature every other day to 50 deg C, once a week to 60 (risk reduction legionella).



Sounds like a faff to me.

I've been swayed towards heating the HW just before it's needed, e.g., daily showers. If heated to 60c it has a lot less time to lose the heat and as it gets used the temp comes down anyway.

If I don't have a regular shower schedule then a 30 min boost before we need it is probably even more efficient. remaining water should be hot enough for other uses the rest of the time.


----------



## Spectric (2 Oct 2022)

Glitch said:


> Perhaps you can give some examples of suppliers manipulating usage.


Thats the problem, you just don't know. Would you notice an extra £1 on a bill. It's how the scammers work on contactless fraud, very small amounts from a lot of people so they don't notice.


----------



## Phil Pascoe (2 Oct 2022)

Glitch said:


> Sounds like conspiracy theory stuff to me. Presumably the suppliers are acting as a cartel and all in on it?
> 
> Perhaps you can give some examples of suppliers manipulating usage.


They will, once widespread - they're not installing them for your benefit.


----------



## Spectric (2 Oct 2022)

But if you believe there advertising they save you money, even Einstein is now backing them and he has been dead for years. Think how much money the suppliers will save once meter readers become history and they can monitor and bill for energy real time.


----------



## Phil Pascoe (2 Oct 2022)

They changed the wording of the ad after I and probably hundreds of thousands of others reported it to the ASA.


----------



## johna.clements (2 Oct 2022)

Spectric said:


> But if you believe there advertising they save you money, even Einstein is now backing them and he has been dead for years. Think how much money the suppliers will save once meter readers become history and they can monitor and bill for energy real time.



Until they introduce dynamic pricing (i think there are some test being undertaken?).

I wonder how many meter readers who whilst being totally unqualified has spotted theft of electricity or an unsafe condition. I would assume that they would have some safety training to say stay away from this it maybe unsafe.


----------



## davethebb (2 Oct 2022)

You will see the best saving when heating your hot water cylinder when the boiler (assuming condensing) is operating at its maximum efficiency e.g. when the return flow is relatively cold. Therefore it is always advisable to try and have the HW heating when on just after the CH comes on. If you check the boiler start-up sequence you will find it probably takes a couple of minutes for the boiler to get to full throttle so you should aim for just after this as this will avoid the cold water being circulated through the HW cylinder, cooling the tank down before the boiler ramps up. It will also mean the return will be a lot colder as it is heating the rads as well as maintaining the boiler at its maximum efficiency. Condensing boilers, if operated outside of the efficiency band are very inefficient. Depending on your rads etc. it may be prudent in the morning during winter not to ramp the room temperature up in one go*** e.g. have the boiler on for an hour as the return water temperature may be high so the boiler runs out of condensing mode - even if it is in condensing mode the colder the return the better.

*** If you have programmable radiator stats, you can use these to introduce colder water flow by opening up different stats, rather than turning the boiler off.

During the summer try and have the boiler fire up only once if you can e.g. consumption and Cylinder size may not allow this.

Food for thought. Hope this makes sense.


----------



## Glitch (2 Oct 2022)

I did have a brief look at return temps on my new boiler. I played around with the output temp.

With the new boiler and pump it is slower to heat up than the old non-condensing boiler. It is cheaper to run though.

Reducing the boiler output temp to bring down the return temp just meant the rads heat up very slowly.

I guess means the system needs the rads to be balanced properly to restrict the flow and bring down return temps.

I suspect few condensing boiler systems are properly set up.

Feels like I'll have a winter project to keep me busy for a while.

In the meantime I'm happy with the Smart meters. No need for tin foil hats in my house.
The data is useful, even if the IHD doesn't work due to firmware issues.


----------



## mikej460 (2 Oct 2022)

I don't support the conspiracy theorists, but is does boil down to either a faulty meter or a second programme on your boiler? Our boiler has 5 separate programmes for example.


----------



## Glitch (2 Oct 2022)

Or a gas leak!


----------



## johna.clements (2 Oct 2022)

or your gas is also connected to another property


----------



## Chris70 (3 Oct 2022)

Glitch said:


> 60-65c is the recommended …


I always subscribed to the idea the Hot Water Setpoint should be 60°C. Now that I have an air-source Heat Pump, the installer has recommended 53°C maximum. Anything higher will cost me ‘big time’. Surprisingly, 53°C now seems adequate. Admittedly, the mixer tap now needs to be ‘all the way round’ to the hot (that is, no added cold) but it’s got to be cheaper, no?

I’m beginning to think the old 60°C stemmed from when energy was dirt cheap the planet didn’t matter!

_Just as an aside, if you’re wondering where I got the ° symbol from, on my iPhone I hover over the zero (0) and it pops up to the left as an option! _


----------



## johna.clements (3 Oct 2022)

Chris70 said:


> I always subscribed to the idea the Hot Water Setpoint should be 60°C. Now that I have an air-source Heat Pump, the installer has recommended 53°C maximum. Anything higher will cost me ‘big time’. Surprisingly, 53°C now seems adequate. Admittedly, the mixer tap now needs to be ‘all the way round’ to the hot (that is, no added cold) but it’s got to be cheaper, no?
> 
> I’m beginning to think the old 60°C stemmed from when energy was dirt cheap the planet didn’t matter!
> 
> _Just as an aside, if you’re wondering where I got the ° symbol from, on my iPhone I hover over the zero (0) and it pops up to the left as an option! _


If you are storing the water at 53C bacteria will grow. 
If you are heating the water and then using it straight away no problem.

The lenght of time that the water is stored hot will determine how many bacteria will grow.


----------



## Glitch (3 Oct 2022)

My HW cylinder is set to 60c (by the heating engineer)
I thought this was to kill off any Legionella. 

Interesting that the official guidance from HSE is 50c min

https://www.hse.gov.uk/pUbns/priced/hsg274part2.pdf Page 31.


----------



## johna.clements (3 Oct 2022)

Glitch said:


> My HW cylinder is set to 60c (by the heating engineer)
> I thought this was to kill off any Legionella.
> 
> Interesting that the official guidance from HSE is 50c min
> ...


Part of page 8 of the above HSE doc

""2.6 Temperature control is the traditional strategy for reducing the risk of legionella
in water systems. Cold water systems should be maintained, where possible, at a
temperature below 20 °C. Hot water should be stored at least at 60 °C and
distributed so that it reaches a temperature of 50 °C (55 °C in healthcare premises)
within one minute at the outlets.""

Part of page 31 my highlight.

"For non-circulating systems: take temperatures at sentinel points (*nearest
outlet, furthest outlet and long branches to outlets)* to confirm they are at
a minimum of 50 °C within one minute (55 °C in healthcare premises)"

50C is the temperature at the tap after one minute of flow. You can not read the temperature inside the water storage tank, you do not know if the thermostat is working perfectly. You can not check it against another thermometer. The thermostat also may not be at the coolest place in the storage tank.


----------



## Spectric (3 Oct 2022)

Glitch said:


> Reducing the boiler output temp to bring down the return temp just meant the rads heat up very slowly.


The wrong approach, condensing boilers work much better when the complete system has been designed around that type of boiler and not as a retofit in an old system. In a new design the radiators are sized larger to handle the lower flow temperature, with the old boilers with high flow temperatures you would aim for an 11° C temperature drop across a radiator. With a condensing boiler you need a 55° return temperature and using a 75° flow temperature gives a 20°C temperature difference across each radiator. To get this increased temperature difference you need larger radiators to deliver the same heat output because of the lower flow temperatures. Just turning down the boiler and reducing the flow temperature will mean less heat output and it will take longer to heat up a room so no savings. It is like a kettle, to boil a litre of water will require a given amount of energy, whether your kettle is 1Kw or 3Kw the energy used will be the same, only the time changes. This is over simplifying it because you need to take into account heat loss, as you slowly increase the temperature over a period of time your heat losses increase, heat it up fast over a short period of time and more of the energy performs useful work and is not lost.


----------



## Glitch (3 Oct 2022)

johna.clements said:


> Part of page 8 of the above HSE doc
> 
> ""2.6 Temperature control is the traditional strategy for reducing the risk of legionella
> in water systems. Cold water systems should be maintained, where possible, at a
> ...


My bad. I did a very quick skim


----------



## Spectric (3 Oct 2022)

With legionella bacteria, they are inactive below 20°C and dead above 60°C. Some newer hot water systems have a legionella cycle where in cases where the temperature has been too low it will perform a hotter cycle. There is also less risk in sealed tanks, I believe this has something to do with nutrients.


----------



## Glitch (3 Oct 2022)

Spectric said:


> With legionella bacteria, they are inactive below 20°C and dead above 60°C. Some newer hot water systems have a legionella cycle where in cases where the temperature has been too low it will perform a hotter cycle. There is also less risk in sealed tanks, I believe this has something to do with nutrients.


 Just had a chat with my heating engineer neighbour. He is upgrading the next door neighbour's system.

Only had time to discuss the unexpected use in the middle of the night.
He's had calls from other customers with similar unexpected use.

He thinks it might be a new software release from Nest that is running a Legionella cycle as suggested by Spectric.
I'll find out what software/firmware changes have happened recently.
I've also switched off the 'Radiant heat' feature, just to eliminate it.


----------



## johna.clements (3 Oct 2022)

Glitch said:


> Just had a chat with my heating engineer neighbour. He is upgrading the next door neighbour's system.
> 
> Only had time to discuss the unexpected use in the middle of the night.
> He's had calls from other customers with similar unexpected use.
> ...


But why run it at that time. Maybe they got confused and it is running at 6pm Pacific Standard Time! then the hot water would be used"


----------



## Richard_C (3 Oct 2022)

It strikes me that the risk of legionella in domestic premises is vanishingly small. The regulations apply to places like schools, hospitals and nursing homes where the consequences could be serious because of the numbers at risk, and things like cooling towers or plant where many people passing by might breathe in vapours.

There was a PHE report in 2016 covering the 3 previous years, total cases sub 400 each year of which between 40 and 50% were overseas travel related. Of those cases, there were few deaths mainly in older people - overall case death rate 7%. So - we can expect about 350 cases each year in the UK, of which 200 are 'home grown; infections of which 14 might die. I think with those case numbers we have bigger things to worry about in a population of 66 million. Take care but don't obsess about it perhaps.

The WHO guidance repeats what has been stated above: 50 degrees at the outlet, 60 at the boiler, and recommends weekly running of otherwise unused taps to prevent stagnation. I doubt many of us have hot taps which we don't use. Cold to be sub 20 degrees, which isn't likely to be a problem in the UK. Its a respiratory disease, you get it by breathing in sray or mist, not from washing your hands in it. I always wonder about the guidance because shower mixers bring the temperature down, but the water entering the mixer should be above 50 in any event. Still though, it could 'breed' in the shower head which never gets above 50 unless you enjoy coming out of the shower very pink. Maybe if we have been away for a few days - stagnant water in shower hose and head - we should run it as hot as hot can be for a few moments before we use it. Care home sthough have one set of regulations requring high temps to avoid legionella and another one requring mixers to be set below a threshold to avoid boiling the residents. Must be hard to reconcile.

Back to the original question, there is no single answer because its lifestyle related and we all live differently. Combi boilers and conventional HW tank systems have wholly different characteristics. We had new boiler, hw tank and so on 18 months ago. The tank is much better insulated than the old one. The hot water flow to the bathroom/shower is pretty efficient, to the downstairs handbasin its OK, to the kitchen it is awful. This dry summer we were collecting water in a washing up bowl to put on plant pots, typically we would run 5 litres before the water got hot at the tap. There are just 2 of us in the house now (what follows all changes if we have family or visitors to stay). 

I used to lazily and unthinkingly have it coming on early am until after we had showered, then again late afternoon for a top up. Calling for heat up to tank thermostat temperature for 2 hours a day. Then I thought, when do we need hot (as in proper-hot) water? Really only to shower each morning plus a bit to wash up things that didn't or couldn't go in the overnight dishwasher run. I'm still unsure about running hot water to the kitchen if its just a small amount to do, a litre in the kettle warmed to 70 and added to a bowl of cold might be quicker and avoids the energy and water wasted in that long pipe run - must do some sums soon.

During the day and evening we only need warm-ish water. I have been pleased to find one 30 minute 'on' cycle just before we get up each day is plenty, and the boiler may only be firing for half of that time. No gas here so its oil, summer usage about 1 litre a day. If I have had a hard-work day in the garden or similar and want an evening shower I just press override and wait 20 minutes or so. No point setting that every day because I don't need it every day. But, we all vary in what we do and what we want so my one half hour cycle a day won't suit all.

As a general principle though, I now think about things a bit more and will set water and heating (coming soon with cool evenings) to the minimum timings and work up from there if I have to rather than my old "just leave it on when we are in" approach. On water, with a decently insulated tank you might be surprised how little you need the boiler to run.


----------



## NormanB (3 Oct 2022)

Glitch said:


> Sounds like a faff to me.
> 
> I've been swayed towards heating the HW just before it's needed, e.g., daily showers. If heated to 60c it has a lot less time to lose the heat and as it gets used the temp comes down anyway.
> 
> If I don't have a regular shower schedule then a 30 min boost before we need it is probably even more efficient. remaining water should be hot enough for other uses the rest of the time.


Why did you say that you do not understand and then contribute something of real value.


----------



## NormanB (3 Oct 2022)

Richard_C said:


> It strikes me that the risk of legionella in domestic premises is vanishingly small. The regulations apply to places like schools, hospitals and nursing homes where the consequences could be serious because of the numbers at risk, and things like cooling towers or plant where many people passing by might breathe in vapours.
> 
> There was a PHE report in 2016 covering the 3 previous years, total cases sub 400 each year of which between 40 and 50% were overseas travel related. Of those cases, there were few deaths mainly in older people - overall case death rate 7%. So - we can expect about 350 cases each year in the UK, of which 200 are 'home grown; infections of which 14 might die. I think with those case numbers we have bigger things to worry about in a population of 66 million. Take care but don't obsess about it perhaps.
> 
> ...


You are absolutely spot on.
The only caveat is a domestic setting with infrequently used showers.


----------



## NormanB (3 Oct 2022)

johna.clements said:


> If you are storing the water at 53C bacteria will grow.
> If you are heating the water and then using it straight away no problem.
> 
> The lenght of time that the water is stored hot will determine how many bacteria will grow.


Not as simple as that.
If you use the water no problem


----------



## Glitch (3 Oct 2022)

I believe I have an answer to the unexplained gas usage.

The Nest system has a Bacteria prevention feature. It will kick in if the HW has not been heating continuous for 2 hours in the past 48 hours. 
I have played around with the HW schedule to use short bursts (less than 2 hours) so the feature will kick in.

It can only be disabled in settings on the thermostat not in the Nest app.






How the Nest thermostat helps prevent Legionella bacteria - Google Nest Help


Legionnaires’ disease is a potentially fatal type of pneumonia that is contracted by inhaling water droplets containing Legionella bacteria. The 3rd-gen Google Nest Thermostat’s Bacteria Preventio



support.google.com


----------



## Richard_C (3 Oct 2022)

Glitch said:


> The Nest system has a Bacteria prevention feature. It will kick in if the HW has not been heating continuous for 2 hours in the past 48 hours.


Well found and explained. Looks like it will render many people's energy reduction attempts pointless unless they realise that nest-knows-best. Seems wasteful to me as chances of infection are low. Even those without second homes (most nest users?) might not run their boiler for 2 consecutive hours except in winter.


----------



## Glitch (3 Oct 2022)

Richard_C said:


> Well found and explained. Looks like it will render many people's energy reduction attempts pointless unless they realise that nest-knows-best. Seems wasteful to me as chances of infection are low. Even those without second homes (most nest users?) might not run their boiler for 2 consecutive hours except in winter.



Nest information seems fairly hard to find. The bacteria prevention feature is not mentioned in the App so people are unlikely to know about it.

I wouldn't have spotted it without the data from the Smart meter.

Now I need to decide whether to disable it or not. Didn't have it before Nest so doubt I need it now, although HW was on longer cycles 

The HW schedule is now 0700 - 08:00 and 14:30 - 15:30 plus ad-hoc boosts when necessary.

Still need to work out how to optimise the heating and boiler efficiency.


----------



## johna.clements (3 Oct 2022)

NormanB said:


> Not as simple as that.
> If you use the water no problem


Not sure what is wrong with my statement.

"If you are storing the water at 53C bacteria will grow.
If you are heating the water and then using it straight away no problem.
The length of time that the water is stored hot will determine how many bacteria will grow"


----------



## davethebb (3 Oct 2022)

Spectric said:


> The wrong approach, condensing boilers work much better when the complete system has been designed around that type of boiler and not as a retofit in an old system. In a new design the radiators are sized larger to handle the lower flow temperature, with the old boilers with high flow temperatures you would aim for an 11° C temperature drop across a radiator. With a condensing boiler you need a 55° return temperature and using a 75° flow temperature gives a 20°C temperature difference across each radiator. To get this increased temperature difference you need larger radiators to deliver the same heat output because of the lower flow temperatures. Just turning down the boiler and reducing the flow temperature will mean less heat output and it will take longer to heat up a room so no savings. It is like a kettle, to boil a litre of water will require a given amount of energy, whether your kettle is 1Kw or 3Kw the energy used will be the same, only the time changes. This is over simplifying it because you need to take into account heat loss, as you slowly increase the temperature over a period of time your heat losses increase, heat it up fast over a short period of time and more of the energy performs useful work and is not lost.


Absolutely correct. You must have a balanced system as far as possible. However, with TRV's this is not always 100% possible because the flow in the system changes - the new learning pumps are good because they compensate for this and reduce electricity consumption at the same time. Don't reduce the boiler output to obtain the reduced return temperature, that is not the correct approach, the key is to achieve the temperature differential the higher the better.


----------



## Glitch (3 Oct 2022)

I get the need for a condensing boiler to run at a lower temp, the need for the temp difference on the return and to use bigger rads.

Sounds like the smart pumps are a recent attempt to give this type of system a chance to work efficiently.

I have 10 radiators and an area of underfloor heating.
Most radiators have TRVs
Most radiators are turned off because it's an empty nest.

I might be able to improve it a bit but I've got little or no chance of getting the best out of the boiler. I'd be surprised if 1 in a 1000 similar systems work optimally.


----------



## Pedronicus (3 Oct 2022)

I certainly would not be turning rads off in unused rooms as the heat from the adjoining rooms will transfer through the walls/ceiling to the colder rooms thereby making the heated rooms colder. If TRVs are fitted then turn them down to a lower setting but not off. If TRV's not fitted then fit some to the 'nest' rooms. You certainly won't be able to correctly balance a system with rads turned off.


----------



## mikej460 (3 Oct 2022)

It's worth pointing out that the legionella risk only applies to direct systems i.e. where the hot water is stored in a tank and is used as needed. In a modern indirect tank in an unvented system (no header tank) the heated water never leaves the tank, simply circulating through the boiler to maintain the set temperature, it then heats the cold water via a heat exchanger once a tap or shower is switched on. You also get power showers at mains pressure.


----------



## Glitch (3 Oct 2022)

Pedronicus said:


> I certainly would not be turning rads off in unused rooms as the heat from the adjoining rooms will transfer through the walls/ceiling to the colder rooms thereby making the heated rooms colder. If TRVs are fitted then turn them down to a lower setting but not off. If TRV's not fitted then fit some to the 'nest' rooms. You certainly won't be able to correctly balance a system with rads turned off.


That seems counterintuitive when trying to cut heating bills.
Surely the TRVs will shut off at low temps and you're back to square one. Unless you have a smart pump?

I should add that I have a wood burner that I'll be using to heat the downstairs on cold evenings and sometimes during the day. I know it probably won't save anything but I prefer a live fire when the opportunity arises.


----------



## Just4Fun (4 Oct 2022)

Pedronicus said:


> You certainly won't be able to correctly balance a system with rads turned off.


I believe I could correctly balance my system if I had fewer rads. How are rads that are turned off any different?


----------



## johnny (4 Oct 2022)

Chris70 said:


> I always subscribed to the idea the Hot Water Setpoint should be 60°C.
> 
> I’m beginning to think the old 60°C stemmed from when energy was dirt cheap the planet didn’t matter!


60 degrees c is the minimum temperature that will kill Legionella any lower and you could contract Legionella which is a potential killer . HSE - Legionnaires' disease - Hot and cold water systems - Things to consider


----------



## Phil Pascoe (4 Oct 2022)

mikej460 said:


> It's worth pointing out that the legionella risk only applies to direct systems i.e. where the hot water is stored in a tank and is used as needed. In a modern indirect tank in an unvented system (no header tank) the heated water never leaves the tank, simply circulating through the boiler to maintain the set temperature, it then heats the cold water via a heat exchanger once a tap or shower is switched on. You also get power showers at mains pressure.


I queried this before and it was pointed out that legionella can get in other ways such as mains repairs.


----------



## Pedronicus (4 Oct 2022)

Just4Fun said:


> I believe I could correctly balance my system if I had fewer rads. How are rads that are turned off any different?


The whole system with all rads on is balanced correctly to start with. Once this is done then rads can be turned off as required. If the system is balanced with rads turned off then, should those rads needs to be turned on again the whole system will be thrown out of balance. At least that is the way I was taught to do it and that has served me well in 40+ years in the heating industry designing/installing in industrial, commercial & domestic applications.


----------



## PDW125 (4 Oct 2022)

As per the front page of that report, it is :
_This guidance is for dutyholders, which includes employers, those in control of premises and those with health and safety responsibilities for others, to help them comply with their legal duties._

As of December 2021 (last reported data) there are no records of legionella in the U.K. from a domestic hot water source. If you have a sealed unvented system then there is no entry point for bacteria, and the chlorine in the water will disinfect the system. Storing at 48-53°C which is the reasonable maximum with a non R32 refrigerant based ASHP. Some newer ones can still reach CoP 2 (ie twice as better as direct electric) at 62°C but the efficiency diminishes rapidly.

If you have gas then an unvented cylinder with a mixing valve can easily go to 75°C and give around 20% additional theoretical tank capacity. Do not do that with a standard cylinder or one without a tank blending valve as the risk of scalding is significant.


----------



## furnace (4 Oct 2022)

Richard_C said:


> to the downstairs handbasin its OK, to the kitchen it is awful.


I have a large, old gaff with long pipe runs. The kitchen tap needed running for ever to get hot water so I installed and undersink water heater that does the job perfectly. I think it's the 15 litre capacity version and provides all the kitchen sink water I ever need, and should it run out, it takes only a few mins to reheat. It was about £100.


----------



## johna.clements (4 Oct 2022)

PDW125 said:


> As of December 2021 (last reported data) there are no records of legionella in the U.K. from a domestic hot water source. If you have a sealed unvented system then there is no entry point for bacteria, and the chlorine in the water will disinfect the system. Storing at 48-53°C which is the reasonable maximum with a non R32 refrigerant based ASHP. Some newer ones can still reach CoP 2 (ie twice as better as direct electric) at 62°C but the efficiency diminishes rapidly.


If people change their actions their risks will change.

There are bacteria in the mains water. Chlorine keeps the numbers in check but you still get requests to boil the water.

Legionella is found in the soil and freestanding water. A certain amount of soil gets into the mains when they carry out works. They put a large dose of chlorine in the pipe they are working on and flush pipes but people do make mistakes. Everybody has seen brown water at times.

Peoples immune systems will fight off bacteria without you noticing if the number is low. If the number is large you have a problem.

The longer water is stored the more bacteria multiply. 

If water is stored above room temperature and is not heated to kill bacteria they will multiply. 


Bacteria is in the water system so we either have to use it quick enough so that they do not grow to dangerous levels or periodically heat the water. Save money by using less hot water and do not heat it as much will allow bacteria to grow, you can not have both. 

If domestic premises change their behavior to be like commercial premises they will have the risks of commercial premises with similar systems.


----------



## Chris70 (4 Oct 2022)

johna.clements said:


> If you are storing the water at 53C bacteria will grow.
> If you are heating the water and then using it straight away no problem.
> 
> The lenght of time that the water is stored hot will determine how many bacteria will grow.


We have a Legionella Routine programmed. The temperature is raised at 02:00 each Wednesday for 2 hours to 60°C. I appreciate your concern, but I think we’ve got that covered.


----------



## NormanB (4 Oct 2022)

Chris70 said:


> I always subscribed to the idea the Hot Water Setpoint should be 60°C. Now that I have an air-source Heat Pump, the installer has recommended 53°C maximum. Anything higher will cost me ‘big time’. Surprisingly, 53°C now seems adequate. Admittedly, the mixer tap now needs to be ‘all the way round’ to the hot (that is, no added cold) but it’s got to be cheaper, no?
> 
> I’m beginning to think the old 60°C stemmed from when energy was dirt cheap the planet didn’t matter!
> 
> _Just as an aside, if you’re wondering where I got the ° symbol from, on my iPhone I hover over the zero (0) and it pops up to the left as an option! _


If you are actually using unmixed hot water at 53C you have unusually tough skin. My mixer thermostat is set for a maximum of 38C and we still mix down. Anything above 40 risks injury.


----------



## NormanB (4 Oct 2022)

johna.clements said:


> Not sure what is wrong with my statement.
> 
> "If you are storing the water at 53C bacteria will grow.
> If you are heating the water and then using it straight away no problem.
> The length of time that the water is stored hot will determine how many bacteria will grow"


Your response to my carefully considered post was ‘Sounds like a faff to me.’

As a lifelong professional engineer I have no time for derisory comments that seek to undermine knowledge.

Our understanding of physics and thermodynamics continues to develop of course but nothing in the last 70 years has undermined the basic laws. Nothing I said contravened them.

In the days of cheap energy (which are likely never to return) we could generally afford to set DHW storage at 60 or even 65 and leave the system under thermostat control 365 days a year.

You could still do that if you are on benefits or have deep pockets but if you are in the ‘squeezed middle’ you will have unnecessarily large bills.

It may be a faff to understand how to match your DHW settings to your lifestyle but exercising the mind does have other benefits too.


----------



## johna.clements (4 Oct 2022)

Chris70 said:


> We have a Legionella Routine programmed. The temperature is raised at 02:00 each Wednesday for 2 hours to 60°C. I appreciate your concern, but I think we’ve got that covered.


Not everybody has a program to heat the tank to 60C at 6pm Pacific Standard Time once a week to sanitize the system. Not sure why that time was choosen would think that 6pm GMT/BST would be more usefull as you could use that heat.


----------



## johna.clements (4 Oct 2022)

NormanB said:


> Your response to my carefully considered post was ‘Sounds like a faff to me.’
> 
> As a lifelong professional engineer I have no time for derisory comments that seek to undermine knowledge.
> 
> ...


 I once again ask what is wrong with my statement.

"If you are storing the water at 53C bacteria will grow.
If you are heating the water and then using it straight away no problem.
The length of time that the water is stored hot will determine how many bacteria will grow" 

As a professional engineer with a life time of experience do you think that bacteria does not grow in warm water?
Do you not think that time is a factor in the number of bacteria.


----------



## Phil Pascoe (4 Oct 2022)

NormanB said:


> If you are actually using unmixed hot water at 53C you have unusually tough skin. My mixer thermostat is set for a maximum of 38C and we still mix down. Anything above 40 risks injury.


I remember hot pools in NZ being 40° - 41°........... only the bravest of Asians went in them.


----------



## johna.clements (4 Oct 2022)

NormanB said:


> In the days of cheap energy (which are likely never to return) we could generally afford to set DHW storage at 60 or even 65 and leave the system under thermostat control 365 days a year.
> 
> You could still do that if you are on benefits or have deep pockets but if you are in the ‘squeezed middle’ you will have unnecessarily large bills.



I am not on benefits so do not know which benefit pays for all your heating bills. My understanding is that all the money is paid together apart from housing which is calculated separately. There is no direct funding of peoples normal gas bills, but if I am wrong please let me know.


----------



## Spectric (4 Oct 2022)

Pedronicus said:


> The whole system with all rads on is balanced correctly to start with.


For info radiators have a user operated valve on one end, might be a TRV and a lockshield valve on the other, this is the valve used to balance your rads.


----------



## Glitch (4 Oct 2022)

NormanB said:


> Your response to my carefully considered post was ‘Sounds like a faff to me.’
> 
> As a lifelong professional engineer I have no time for derisory comments that seek to undermine knowledge.
> 
> ...



For a professional engineer your attention to detail is lacking. You're having a pop at @johna.clements for a comment I made.

You said:
'Second in broad terms (all other things being equal) the hotter you drive your water temperature up the greater the rate of heat loss. You need to match your DHW schedule to your useage. *We have a 210 litre DHW cylinder and raise the temperature every other day to 50 deg C, once a week to 60 (risk reduction legionella).'*

Sounds like you are making manual adjustments every other day. I said that's a faff. That's not intended as a derisory comment, just an observation.
It's not undermining your knowledge, it's an opinion on the manual process you have created for yourself.
I've discovered my Nest system has a Bacteria Protection feature that does this automatically. It's a faff free solution to the Legionella risk.

I can only make a general assumption on how sensitive people might be and I know it's easy to misinterpret a comment. I do it regularly myself but usually double check and puts my hands up if I've read it wrong.


----------



## NormanB (4 Oct 2022)

Glitch said:


> For a professional engineer your attention to detail is lacking. You're having a pop at @johna.clements for a comment I made.
> 
> You said:
> 'Second in broad terms (all other things being equal) the hotter you drive your water temperature up the greater the rate of heat loss. You need to match your DHW schedule to your useage. *We have a 210 litre DHW cylinder and raise the temperature every other day to 50 deg C, once a week to 60 (risk reduction legionella).'*
> ...


I am doing nothing manually, it’s all pre programmed including the once per week ‘hygiene cycle’ of a 60 degree programme.

Yes I made an error as my response was intended for you and not the ‘other guy’ - I have no excuse other than navigating multiple screens on a small phone.


----------



## ivan (4 Oct 2022)

We have a very large shoulder ht. cylinder, as on economy 7. The thermostat at the base of the cylinder has been set to 50 deg for the last 33 years. I guess it might get hotter at the top. We have been free of legonaires so far...


----------



## NormanB (4 Oct 2022)

NormanB said:


> I am doing nothing manually, it’s all pre programmed including the once per week ‘hygiene cycle’ of a 60 degree programme.





johna.clements said:


> I once again ask what is wrong with my statement.
> 
> "If you are storing the water at 53C bacteria will grow.
> If you are heating the water and then using it straight away no problem.
> ...


First off apologies my comment was misdirected at you rather than the o/p.

Secondly, yes if you are storing hot water and not using it, then yes this can promote bacterial growth but you must then ask why are you using energy to store hot water without using it. A weekly hygiene cycle will ameliorate bacteriological growth and also minimise legionella risk in what is, anyway , a low risk domestic environment.


----------



## Glitch (4 Oct 2022)

Spectric said:


> For info radiators have a user operated valve on one end, might be a TRV and a lockshield valve on the other, this is the valve used to balance your rads.



Back to the challenge of optimising the Boiler/radiator performance.

I get the feeling that the condensing boiler would prefer the set up to be static with no variables to affect the performance.

A little knowledge is a dangerous thing but this is what I've gleaned from t'internet 'experts':
Traditionally you open up all the rad valves and find out the order in which they heat up.
Then the rads nearest the boiler and those in the upper stories (heat rises) have their lockshields restricted to a quarter turn open.
This is because the rads that heat up quicker need to reduce the flow through the rad to have min 12c difference between input and output flow to the rad.
Idea is to get some flow to the downstream rads to make sure they don't take ages to heat up and that heat is used to heat the rads and not just returned to the boiler.
Return temp should ideally be 20c less than boiler output temp.
There may be some nuances but I think that's the basic idea.

All work well if everything stays the same, including outside temp and humidity, indoor temperature (and humidity?), Radiator valves are not touched. HW heating doesn't kick in.
So it's better to keep all rads on. TRVs will disrupt the flow because they'll close the valve and push flow to downstream rads, and/or worse still, the boiler.
Turning off rads not needed will affect the balance, dependent on whether they are close to boiler or upstairs. 

From my limited understanding it's a tricky problem to solve. There are too many variables that can affect the initial optimisation. 
That's why someone came up with a smart pump and also other gadgets to help solve the problems.









The DIY gadgets that could keep your energy bill down


With a little know-how people are tuning their home heating to reduce their gas consumption.



www.bbc.co.uk


----------



## NormanB (4 Oct 2022)

johna.clements said:


> I am not on benefits so do not know which benefit pays for all your heating bills. My understanding is that all the money is paid together apart from housing which is calculated separately. There is no direct funding of peoples normal gas bills, but if I am wrong please let me know.


Local Authorities have been allocated central funding for these purposes. Only those on benefits can access these local authority ‘hardship funds’.




__





Household Support Fund: guidance for local councils


Information for local councils on the Household Support Fund to support vulnerable households in England.




www.gov.uk


----------



## Glitch (4 Oct 2022)

NormanB said:


> I am doing nothing manually, it’s all pre programmed including the once per week ‘hygiene cycle’ of a 60 degree programme.
> 
> Yes I made an error as my response was intended for you and not the ‘other guy’ - I have no excuse other than navigating multiple screens on a small phone.



No problem. 
You have an automated solution which is good. 

Can you detect and boiler out and return flow temps, or is it just the water storage temperature that you can set?
I'm wondering if you have enough flexibility to tune the boiler in real time.


----------



## johna.clements (4 Oct 2022)

NormanB said:


> Local Authorities have been allocated central funding for these purposes. Only those on benefits can access these local authority ‘hardship funds’.
> 
> 
> 
> ...


That is discretionary spending, only some people will get it. If the fund runs out hard luck. You have to give a reason why you should get money from this hardship fund. If you needed additional electricity to run medical equipment you could get a grant if the money has not already been spent. If as you suggest you just want to walk around the house in your underwear when it is freezing outside with the windows open they will not give you a discretionary grant.

Your suggestion that people on benefits can use as much gas and electric as they want, and it will be paid by central government or local authorities, is nonsense.


----------



## johna.clements (4 Oct 2022)

Glitch said:


> All work well if everything stays the same, including outside temp and humidity, indoor temperature (and humidity?), Radiator valves are not touched. HW heating doesn't kick in.
> So it's better to keep all rads on. TRVs will disrupt the flow because they'll close the valve and push flow to downstream rads, and/or worse still, the boiler.
> Turning off rads not needed will affect the balance, dependent on whether they are close to boiler or upstairs.
> 
> ...


 I think the question should be what is the cost/ benefit of running the system at different efficiencies. If you turn down the radiators in little used rooms will you be better off financially even though the boiler may then not be working as efficiently. If you save £100 a year to turn down the radiator in the box room, that has boxes in it, but the rest of the house costs £20 more to heat you gain £80.

I would assume that is how it works but I am a civil engineer not HVAC.


----------



## dillon (4 Oct 2022)

Chris70 said:


> I always subscribed to the idea the Hot Water Setpoint should be 60°C. Now that I have an air-source Heat Pump, the installer has recommended 53°C maximum. Anything higher will cost me ‘big time’. Surprisingly, 53°C now seems adequate. Admittedly, the mixer tap now needs to be ‘all the way round’ to the hot (that is, no added cold) but it’s got to be cheaper, no?
> 
> I’m beginning to think the old 60°C stemmed from when energy was dirt cheap the planet didn’t matter!
> 
> _Just as an aside, if you’re wondering where I got the ° symbol from, on my iPhone I hover over the zero (0) and it pops up to the left as an option! _


My understanding, from an HSE inspector, is that 60 degrees is guaranteed to kill bacteria, particularly Legionella. If this is indeed the case you may want a word with your installer.


----------



## Glitch (4 Oct 2022)

johna.clements said:


> I think the question should be what is the cost/ benefit of running the system at different efficiencies. If you turn down the radiators in little used rooms will you be better off financially even though the boiler may then not be working as efficiently. If you save £100 a year to turn down the radiator in the box room, that has boxes in it, but the rest of the house costs £20 more to heat you gain £80.
> 
> I would assume that is how it works but I am a civil engineer not HVAC.



I get what you're saying.

Apparently the maximum benefit you can get with a condensing boiler is 11% more efficiency than a non-condensing one. 
My maximum saving, based on my latest London Power direct debit is £288 p.a.

Few will get anywhere near the full 11% benefit so let's assume I could get 5.5%.

So the target saving is around £144 p.a. 

When the weather gets cold enough for me to turn the heating on I'll start tweaking.


----------



## NormanB (5 Oct 2022)

Glitch said:


> No problem.
> You have an automated solution which is good.
> 
> Can you detect and boiler out and return flow temps, or is it just the water storage temperature that you can set?
> I'm wondering if you have enough flexibility to tune the boiler in real time.


My boiler regulates itself to achieve a Delta T of 20C across the boiler heat exchanger, DHW cylinder temperature is on its own stat. On heating duty I have zero room room thermostats and control is effected using weather compensation and during commissioning the slope and origin of the control curve was set up to match the heat loss of the house. It is an iterative process (at different ambients) and no heating engineer working for a customer would spend the time required to optimise it as I have. But once set up that’s it and it will use the minimum of energy to keep the house at ‘set point’ monitoring outside ambient to ensure minimum burn (boiler modulates down to 1.9KW) ensuring maximum condensing at the hex.

It is a Viessman 200W fitted with priority DHW on a 4 pipe system. I also fitted IMI constant flow valves on all radiators (these are set to match flow rate to emitter capacity ) so no need for guesstimate balancing on low authority lockshield valves (which are honestly not really up to that task). Standard (non smart) TRVs fitted on every emitter (radiator).

I also range rated my boiler to 6KW to match the heat loss of my house (did my own heat loss calcs).

In my opinion the Viessman 200 has the best boiler controls and modulation in the current market.


----------



## 1steven (5 Oct 2022)

Viessman are great boilers


----------



## johnny (5 Oct 2022)

furnace said:


> I have a large, old gaff with long pipe runs. The kitchen tap needed running for ever to get hot water so I installed and undersink water heater that does the job perfectly. I think it's the 15 litre capacity version and provides all the kitchen sink water I ever need, and should it run out, it takes only a few mins to reheat. It was about £100.


thats an excellent solution. We have the same problem with along run from our boiler on the first floor to our kitchen sink. Extremely wasteful waiting for all that pipework to heat up and inconvenient when all you need is a bowlful of hot water for washing up. I am going to fit an undersink water heater shortly too.


----------



## johnny (5 Oct 2022)

Back in 2005 I was the Surveyor responsible for maintaining the Legionella register for one of the Somerset Councils for a year or so. This was for all public buildings owned and used by the Public. Naturally we had to have a constant ongoing program of surveys , risk assessments, remedial works and treatment and I was required to attend several courses on the subject. 

It was an onerous task, not least because legally as the person responsible for the legionella Register I would have been personally liable for any deaths or short comings in the register ,...not the Council ! The register was inspected regularly and I remember that there had been numerous well publicised Deaths from Legionaires Disease around the Country .

There are a lot of simplistic uninformed and misleading opinions about the risks and mitigation of of Legionella on the internet but the Government guidelines are a useful source of information Managing legionella in hot and cold water systems


----------



## Suffolk Brian (5 Oct 2022)

Pardon me for showing my ignorance, but can someone explains what a “smart” pump is, and how it would be controlled? Does it rely on some form of instruction from the boiler, or is it a freestanding unit that could be retrofitted to an existing system?


----------



## Chris70 (5 Oct 2022)

...and while we're on Boiler recommendations (we are, aren't we?) avoid Keston. What do I know?


----------



## Phil Pascoe (5 Oct 2022)

I spent a couple of months in a small hospital in 2014. Everyone knew that to get a decent shower you had to unscrew the legionella filters fitted to the shower heads. They were fitted and forgotten until water could no longer find its way through them.


----------



## Glitch (5 Oct 2022)

NormanB said:


> My boiler regulates itself to achieve a Delta T of 20C across the boiler heat exchanger, DHW cylinder temperature is on its own stat. On heating duty I have zero room room thermostats and control is effected using weather compensation and during commissioning the slope and origin of the control curve was set up to match the heat loss of the house. It is an iterative process (at different ambients) and no heating engineer working for a customer would spend the time required to optimise it as I have. But once set up that’s it and it will use the minimum of energy to keep the house at ‘set point’ monitoring outside ambient to ensure minimum burn (boiler modulates down to 1.9KW) ensuring maximum condensing at the hex.
> 
> It is a Viessman 200W fitted with priority DHW on a 4 pipe system. I also fitted IMI constant flow valves on all radiators (these are set to match flow rate to emitter capacity ) so no need for guesstimate balancing on low authority lockshield valves (which are honestly not really up to that task). Standard (non smart) TRVs fitted on every emitter (radiator).
> 
> ...



That sounds impressive. Was it an upgrade, or a complete new system. New build house?

Did you design this yourself?


----------



## Glitch (5 Oct 2022)

Suffolk Brian said:


> Pardon me for showing my ignorance, but can someone explains what a “smart” pump is, and how it would be controlled? Does it rely on some form of instruction from the boiler, or is it a freestanding unit that could be retrofitted to an existing system?



I think I assumed there might be some truly integrated pumps and called them Smart.

The one @Spectric mentioned is this one.






Grundfos Alpha1 Alpha1 15-50/60 130 circulating pump | Wolseley


Looking for a Grundfos Circulating Pump 222025 PK? Order from Wolseley today - free delivery or click and collect available nationwide.




www.wolseley.co.uk





It automatically adjusts the pressure. The brochure says:

'Contrary to an uncontrolled pump, the proportional pressure-controlled ALPHA1 pump reduces the differential pressure in case of falling heating demand'


----------



## leisurefix (5 Oct 2022)

NormanB said:


> I also fitted IMI constant flow valves on all radiators (these are set to match flow rate to emitter capacity ) so no need for guesstimate balancing on low authority lockshield valves (which are honestly not really up to that task). Standard (non smart) TRVs fitted on every emitter (radiator).


Really interested in these, or similar. Am just researching replacing Combi boiler with a condensing boiler, and any other appropriate upgrades. 
There are some really useful posts in this thread, I had not realised the differences with condensing boilers & importance of temperature drops across radiators & return temperature for example. Are flow valves worth the expense? Or will a well balanced (14 radiators all turned on to fairly low output with TRVs) system achieve similar results, with a bit of ongoing maintenance? 
IMI Hydronic products don't seem easily available in UK, so are there alternate products, or a recommended UK stockists that elude Google.
Thanks


----------



## Glitch (5 Oct 2022)

leisurefix said:


> Really interested in these, or similar. Am just researching replacing Combi boiler with a condensing boiler, and any other appropriate upgrades.
> There are some really useful posts in this thread, I had not realised the differences with condensing boilers & importance of temperature drops across radiators & return temperature for example. Are flow valves worth the expense? Or will a well balanced (14 radiators all turned on to fairly low output with TRVs) system achieve similar results, with a bit of ongoing maintenance?
> IMI Hydronic products don't seem easily available in UK, so are there alternate products, or a recommended UK stockists that elude Google.
> Thanks











IMI Hydronic Eclipse Angled TRV Thermostatic Radiator Valve & Lockshield Set 15mm


Features: The thermostatic head with incompressible liquid-filled sensor guarantees a reliable and precise room temperature control. This automatic flow limitation is done with a twist and the adjus...DISCLAIMERThis product qualifies for next day delivery provided it is in stock and your...




www.mpmoran.co.uk


----------



## Fergie 307 (5 Oct 2022)

furnace said:


> I have a large, old gaff with long pipe runs. The kitchen tap needed running for ever to get hot water so I installed and undersink water heater that does the job perfectly. I think it's the 15 litre capacity version and provides all the kitchen sink water I ever need, and should it run out, it takes only a few mins to reheat. It was about £100.


Use a similar setup for hot water at a sink in the workshop. Very easy installation and works a treat.


----------



## NormanB (6 Oct 2022)

Glitch said:


> That sounds impressive. Was it an upgrade, or a complete new system. New build house?
> 
> Did you design this yourself?


Replacement system. I specified the ‘design’ and equipment selection. I also upscaled four existing radiators so the system as a whole would be more effective with the lower temperature circulating temps.

I did room by room heat loss calculations which informed me which emitters needed upscaling and the summation of all room heat losses gave me the total heat loss for the house which enabled me to select the correct size boiler. I was then able to tell the heating engineer what capacity to range rate the boiler to.

The heating engineer was a pleasure to work with.


----------



## NormanB (6 Oct 2022)

leisurefix said:


> Really interested in these, or similar. Am just researching replacing Combi boiler with a condensing boiler, and any other appropriate upgrades.
> There are some really useful posts in this thread, I had not realised the differences with condensing boilers & importance of temperature drops across radiators & return temperature for example. Are flow valves worth the expense? Or will a well balanced (14 radiators all turned on to fairly low output with TRVs) system achieve similar results, with a bit of ongoing maintenance?
> IMI Hydronic products don't seem easily available in UK, so are there alternate products, or a recommended UK stockists that elude Google.
> Thanks


The fundamental problem with trying to balance a system using conventional lock shield valves is you are setting up for one condition only and as TRVs operate a new set of variables kick in. I had no problem sourcing IMI valves - on holiday at the moment - but will try and remember to post a link to a supplier. There is also an IMI app for setting up calculations which may give supplier contact details.

Here is one example: Eclipse TRV + Thermostatic head DX – Hydronics Direct

But shop around.


----------



## NormanB (6 Oct 2022)

Suffolk Brian said:


> Pardon me for showing my ignorance, but can someone explains what a “smart” pump is, and how it would be controlled? Does it rely on some form of instruction from the boiler, or is it a freestanding unit that could be retrofitted to an existing system?


The smartest of smart pumps are burner linked pumps so the more gas being burned the greater the pump output and vice versa. Normally achieved by controlling Delta T across the heat exchanger.


----------



## NormanB (6 Oct 2022)

Much has been written in this thread with respect of stored hot warter temperature and potential legionella risks. Overall the absolute risk is small in most domestic properties but there are factors that require consideratio.

i commend this video to those interested in this subject and in fact this chaps You Tube channel to further your understanding of heating systems in general be they gas boilers or heat pumps.



BTW. I have a 210 litre cylinder, thermostat set at 45c and the boiler is programmed for a ‘hygiene cycle‘ of 60c once per week.


----------



## Phil Pascoe (6 Oct 2022)

A little larger than my tank, but not much. Mine is electric only, and inaccessible - it's in the roof. I wonder how long it take for the upper of the two elements to heat the the whole tank to 60°? This could be turned on once a week. The hygiene cycle is once a week? The water in my (mains pressure) tank probably turns over every two or at most three days, so I wonder how much danger there actually is there.


----------



## furnace (11 Oct 2022)

johnny said:


> thats an excellent solution. We have the same problem with along run from our boiler on the first floor to our kitchen sink. Extremely wasteful waiting for all that pipework to heat up and inconvenient when all you need is a bowlful of hot water for washing up. I am going to fit an undersink water heater shortly too.


A note of caution. If the model you choose requires a sacrificial anode, stick the date of the required change in your diary and write it on the unit as a reminder. Depending on the hardness of your water, it's just a matter of time before it will corrode and leak if the anode is not changed. DAMHIK.
I believe versions are available with stainless steel tanks that don't require anodes.


----------



## Adam W. (11 Oct 2022)

We have a system boiler with a 30 litre tank and I stuck a circulator pump on the DHW, so we get hot water at the tap straight away, even though its 15m from the water tank.


----------



## furnace (11 Oct 2022)

Adam W. said:


> We have a system boiler with a 30 litre tank and I stuck a circulator pump on the DHW, so we get hot water at the tap straight away, even though its 15m from the water tank.


Do you find it cools the tank unduly? I tried that on my bathroom, and even with insulation around the pipes (running through the loft) it sucked too much heat from the cylinder causing the water to be lukewarm. I took it out, and have now got used to waiting 2 mins before getting in the shower...


----------



## Adam W. (11 Oct 2022)

No, the water is just fine and it seems to have increased the amount of hot water for showers.

It's nice knowing that we're not wasting 7.5 litres of hot water every time we run the kitchen or bathroom taps, I think it has saved us an enormous amount of gas and water over the year. I think it works well, as we only have a 30 litre tank, so it's not mixing the layers of hot and cold water in the tank.

I'm looking at putting in a solar hot water system with panels, using a 1000 litre tank as the storage battery for the panels, instead of trying to power the electricity supply to the house.


----------



## furnace (11 Oct 2022)

Adam W. said:


> No, the water is just fine and it seems to have increased the amount of hot water for showers.
> 
> It's nice knowing that we're not wasting 7.5 litres of hot water every time we run the kitchen or bathroom taps, I think it has saved us an enormous amount of gas and water over the year. I think it works well, as we only have a 30 litre tank, so it's not mixing the layers of hot and cold water in the tank.
> 
> I'm looking at putting in a solar hot water system with panels, using a 1000 litre tank as the storage battery for the panels, instead of trying to power the electricity supply to the house.


Solar thermal panels to the tank, or solar PV powering an immersion in the tank?


----------



## Just4Fun (11 Oct 2022)

Adam W. said:


> ... I stuck a circulator pump on the DHW


Did you use a bronze pump or similar? I used a common or garden central heating pump and had 2 or 3 fail. I am told I should have used a non-ferrous pump but at the moment I have the last failed pump still in place.


----------



## Adam W. (11 Oct 2022)

@Just4Fun It's a stainless Grundfos pump, they have the suffix N. I got it off ebay for £100









ALPHA2 N


ALPHA2 N is a circulator pump with stainless-steel pump housing for domestic hot-water systems. AUTOADAPT continuously adapts the pump to system demands for optimal comfort and low energy consumption.




product-selection.grundfos.com





@furnace PV on an immersion is what I'm interested in at the moment, but that may change.


----------



## Spectric (11 Oct 2022)

Adam W. said:


> and I stuck a circulator pump on the DHW


Those pumps are not cheap, £200 for the Grunfoss that I fitted into the hot water for recirculating.


----------



## Spectric (11 Oct 2022)

Just4Fun said:


> I used a common or garden central heating pump


Not compliant with potable water regs.


----------



## Just4Fun (11 Oct 2022)

Spectric said:


> Not compliant with potable water regs.


Interesting. TBH I have no clue whether the regs are the same over here. It never occurred to me to check. It was certainly a bad move as far as reliability goes though.


----------



## Adam W. (11 Oct 2022)

It's because a regular pump will rust, as it's dealing with mains water when used as a DHW circulator.


----------



## Spectric (11 Oct 2022)

Adam W. said:


> It's because a regular pump will rust, as it's dealing with mains water when used as a DHW circulator.


It's more to do with the fact you cannot use corrosion inhibitor in your hot water system to prevent corrosion.


----------



## Adam W. (11 Oct 2022)

Spectric said:


> It's more to do with the fact you cannot use corrosion inhibitor in your hot water system to prevent corrosion.



I thought that was obvious.


----------



## Spectric (11 Oct 2022)

Maybe to some but don't take anything for granted, assuming something is obvious can easily mean you overlook something and people are more than capable of anything.


----------



## Glitch (12 Oct 2022)

As an aside. 
I've left my room thermostat (in the hall) at 16.5c 06:30-22:30 each day. 
Normally by this time of year it would be on 21c.
It has been mild recently but the temp in the hall has been between 17c-19.5c at around 07:30.
End of day it has risen to 18c-20c just by having the sun on the front of the house.

No more walking around in my pants and a t-shirt in the mornings. 

Bills might still be higher than before but saved unnecessary use of gas.

Wood burner used for the first time yesterday evening. Just a few logs to take the chill off.


----------



## Adam W. (12 Oct 2022)

Spectric said:


> Maybe to some but don't take anything for granted, assuming something is obvious can easily mean you overlook something and people are more than capable of anything.



I'm pretty sure that we all know that DHW is an open system and that if you add inhibitor, it will end up in the drain, as most of us do have hot water taps in our dwellings.


----------



## Phil Pascoe (12 Oct 2022)

Spectric's point was perfectly valid - sometimes the most obvious things are the first/easiest missed.


----------



## Jacob (12 Oct 2022)

Big combi boiler is good. Hot water on demand - no tanks or storage. 
Optimising CH controls - we turn rads on if room is cold and off if too warm, or room not being used.


----------



## Adam W. (12 Oct 2022)

Jacob said:


> Big combi boiler is good. Hot water on demand - no tanks or storage.
> Optimising CH controls - we turn rads on if room is cold and off if too warm, or room not being used.


Yes, it's all very well for you to say that Jacob, but not everyone would be able to figure that out for themselves. Apparently we're a bit thick in this neck of the woods.


----------



## Glitch (12 Oct 2022)

Jacob said:


> Big combi boiler is good. Hot water on demand - no tanks or storage.
> Optimising CH controls - we turn rads on if room is cold and off if too warm, or room not being used.



No good for me.
Low mains pressure. 
Two bathrooms, 10 radiators.

Is your heating on all the time then and just controlled by radiator valves?


----------



## Jacob (12 Oct 2022)

Glitch said:


> No good for me.
> Low mains pressure.
> Two bathrooms, 10 radiators.
> 
> Is your heating on all the time then and just controlled by radiator valves?


Controlled by on/off thermostat in main living room with rad left open. You have to have at least one open when the system gets switched on - I presume - not sure what happens if you don't!
Could take the thermostat to another room if desired, but never do.
Thermostat is programmable but we never bother except it's currently set to come on if the inside temp drops to 13º which it never does, so it's just on/off and adjust rads if necessary.
Haven't had CH on since last winter so it just does DHW. 
Have been room heating with wood stove alone - rocket-stove fashion i.e. small charge of small dry stuff burning fast for quick heat output. Can warm the room very quickly just burning a few scraps and bits of cardboard. Having to reduce the sizes in my log pile for faster burning. You can see the difference on the glass - it doesn't soot up like it used to as it's doing a faster and cleaner burn most of the time.
Also have insulation everywhere i.e. is most important issue of all and most cost effective in the medium term though I haven't done any calcs on that one.
Did calcs on DG - would never pay for itself, totally cost ineffective, though this may change with fuel costs of course.


----------



## johna.clements (12 Oct 2022)

Phil Pascoe said:


> Spectric's point was perfectly valid - sometimes the most obvious things are the first/easiest missed.


If people do not think this is true they think about all the times people say "I didn't think".


----------



## Spectric (12 Oct 2022)

There was some case where someone was trying to help a person fix a Pc over the phone, they went through many potential faults but it was only when they ask the person to look at the connectors and they replied " I will need a torch because we have a power cut that the penny dropped".


----------



## johna.clements (12 Oct 2022)

My brother does programming with a bit of support for the programs he has written. He has stopped using the instruction "hit any key".


----------



## Glitch (30 Nov 2022)

As an update. HW schedule has been tweaked to incorporate a 2 hour blast every couple of days to stop it automatically heating water in the middle of the night.

Have managed not to put the heating on since summer. Target has been today - end of November.

Left thermostat on a summer setting of 16.5c and the lowest it has been is 17.5c. Last year we would have had it set to 21c and the house would be overheated. 

We have had the log burner on in one room when it has felt too cold. 
Without heating the house feels damp at times so I've been using the dehumidifier during the day. 

Not running the tumble dryer, which we used to not give a second thought about using in winter. Instead the dehumidifier has a laundry setting and it does an amazing job of drying the clothes in a couple of hours in a spare bedroom. It doesn't cost much to run.

Definitely changed our approach to heating the house and our winter gas usage has dropped dramatically.

Weather has been pretty mild so far. As it gets colder I'll probably set the thermostat to 18c to keep the background heat up.

I think this will permanently change our approach to energy use.


----------



## Pedronicus (30 Nov 2022)

Glitch said:


> Instead the *dehumidifier* has a laundry setting and it does an amazing job of drying the clothes in a couple of hours in a spare bedroom. It doesn't cost much to run.


Which make & model would that one be please. Thnx.


----------



## Glitch (30 Nov 2022)

Pedronicus said:


> Which make & model would that one be please. Thnx.











MeacoDry Arete® One 25L Dehumidifier / Air Purifier


The very best in dehumidifier design Welcome to the latest in dehumidifier design: the new Arete range. This collection has been in development for five years, with our dedicated British design team working closely with more than 2000 customers to find out exactly what makes the perfect...




www.meaco.com





Might have stock problems.

Also look at Ebac. They lost their top spot to Meaco due to Which reviews. Ebac hotly dispute the way Which tested the products.


----------

