Radiator TRVs. Does anyone want to talk me out of removing them?

[DiyAddict]

Yet another upstairs radiator TRV has started leaking, and like the many previous occasions, has made a mess of the ceiling below. There are a lot in my house, fitted before I moved in 20 years ago, and though the original ones occasionally fail, I find newer replacement ones start leaking within a few years. The replacements are mid-range ones.

Maybe I didn't spend enough on high quality replacements, but I'm starting to think they're all a waste of time. I'm on the verge of taking them out and replacing the lot with standard radiator taps. I only ever adjust them between zero and maximum anyway, and if the system is well-balanced, I can't see a problem. I've had five go in the last five years, with predictable results in the rooms below.

Is this a bad idea? Is there a brand of TRVs that are 100% reliable?

 

[Spectric]

These TRV's did become over used, originaly only fitted in upstairs bedrooms to keep the room temperatures lower than the main living area that was controlled by the thermostat. Now we want total control and you get many systems but some are just not energy efficient in some larger properties, the ideal system is zoned with each zone having it's own stat and zone valve. The wireless TRV's that are now around can be a pain, think of where just one room falls below temperature and the boiler fires to supply that rooms radiator with hot water via a long pipe run. If you want good valves look at Honeywell , Pegler and some of the Drayton valves and don't bother with any hype about liquid filled, the wax capsule types are fine.

If you remove the TRV's you might find the upstairs gets to hot.

 

[Stuart Moffat]

I’ve never had one fail, either functionally or leaking. I’ve only ever bought Honeywell ones. I put 15 of them in our current house 16 years ago, and similar in the house before that.
Stuart

 

[Adam W.]

Likewise, I use the Danfoss RA-dv ones with the Danfoss RAX sensors. Pricey, but I never have a problem even when re-using them.

 

[Spectric]

I’ve never had one fail, either functionally or leaking. I’ve only ever bought Honeywell ones.

Quality pays, never be tempted by the cheaper ones on offer in places like Screwfix and also tread carefully with some of the so called designer ones where the looks have taken priority over quality.

 

[Geoff_S]

How well do the TRVs with a remote thermostat work, if anyone has experience of them.

I ask because a few of my radiators are inside cabinets.

Ta

 

[Spectric]

There are some TRV's that have a remote capsule attached via a thin copper capillary tube that provides remote temperature sensing for situations where the actual valve is not exposed to the room temperature.

https://www.wolseley.co.uk/product/drayton-angled-trv4-and-remote-head-15mm-2mtr/
https://www.screwfix.com/p/pegler-w...VxLHtCh2TrwrTEAQYAiABEgJhNvD_BwE&gclsrc=aw.ds

 

[Sideways]

With too many of the TRV's closed, as I understand it the return temperature of your boiler could end up higher than intended when it was balanced so the boiler is no longer condensing and it runs at a poor efficiency. Get this wrong and turning off those "unnecessary" rads may not actually save any gas...

 

[eribaMotters]

Stelrad radiators and Danfoss TRV's is the ideal combination. I used this set-up in previous houses, upgrading old systems and never had any issues. I was strongly advised to avoid cheap TRV's and did so.

Colin

 

[Bingy man]

Should have 1 rad without trv or aromatic bypass built into boiler pipe work for just scenario- as per above posts quality is important and Drayton trv4 or peeler have served me well over the years .Honeywell were decent but the heads were on the large side for some customers.

 

[Stuart Moffat]

Sometimes auto correct comes up with a gem. Can’t tell what “aromatic bypass” did to my imagination!

 

[Bingy man]

That should be pegler in case anyone is offended

 

[DiyAddict]

Thanks a million guys. Here's the leaky TRV, which uses a plastic nut to pack the o-ring onto the pin. You can see that the sleeve has sheared off from the plastic nut due to the water pressure. My older TRVs have brass ones, hence them lasting longer.

As tempting as it is to curse modern cheapskating, I've since read that this can also be due to various other causes - unbalanced system, pump pressure too high etc. But a brass nut wouldn't have failed.

Anyway, you've collectively talked me out of getting rid of the TRVs. Instead, I'm going to drain the system in the summer and replace all the TRVs with Honeywell/Pegler/Drayton/Danfoss ones, then get a plumber to balance the system and make sure the pressure is correct.

Thanks again, Paul

 

[Richard_C]

Wise decision, avoids endless tweaking of tail valves to balance flow in rads in little used rooms. 18 months ago we had a new boiler so I replaced all 16 TRVs which were 33 years old, Honeywell. In the 25 years I lived here before that a few had failed to open/close properly and needed new heads but I never had a failure resulting in a leak. You do need an always on non TRV radiator and/or a bypass, I wonder if a wrongly set pump or even too big a pump could increase the chance of leakage?

 

[NormanB]

Thanks a million guys. Here's the leaky TRV, which uses a plastic nut to pack the o-ring onto the pin. You can see that the sleeve has sheared off from the plastic nut due to the water pressure. My older TRVs have brass ones, hence them lasting longer.

As tempting as it is to curse modern cheapskating, I've since read that this can also be due to various other causes - unbalanced system, pump pressure too high etc. But a brass nut wouldn't have failed.

Anyway, you've collectively talked me out of getting rid of the TRVs. Instead, I'm going to drain the system in the summer and replace all the TRVs with Honeywell/Pegler/Drayton/Danfoss ones, then get a plumber to balance the system and make sure the pressure is correct.

Thanks again, Paul

To be honest if you are going to all the trouble of draining, replacing TRVs, refilling and venting I am not at all sure why you would pay a plumber to balance the system. Balancing is straightforward but very time consuming. If you have the time to do the valve swap surely you have the time to dedicate to balancing. Most plumbers ‘wing it’ and will be in and out of the house in an hour.

You do need to know what DT across your boiler heat exchanger (check the book) Older boilers DT10, newer ones DT20 and you should mirror this with your DT across the rads.

 

[eribaMotters]

Interesting to see good comments on Draytons. I was advised not to retro fit them onto an existing system as they are prone to faults, but fine if on a new installation. I'm guessing this is down to the crap that accumulates in the pipework over years.

Colin

 

[joncooper27]

Can anybody recommend any smart valves? I have been looking at Fibaro Valves with the Fibaro Home Centre controller!

 

[Spectric]

Keep it simple, once you go down a particular route with some supplier you may get problems in the future with parts or the company may not even exist. With a more simple system using more conventional components you have far more options and it is always easier to install a decent system from scratch than a retrofit because having a proper zoned system is a better way to go but requires more pipework. I also keep everything well away from any so called app because I much prefer hardwired control systems.

 

[yngndrw]

Regarding zoning and TRVs, you may want to look at the Heat Geek video on the subject: (They specialise in heat pumps, but the same concepts apply to condensing boilers as well - Just boilers are far more forgiving)

(Why not to zone heat pumps or boilers - There are some fantastic worked examples in this video along with explanations about the maths behind it)


The video has a primary focus on heat pumps, but it does cover boilers as well. It also happens to explain how a poor heat pump install can ruin the reputation for heat pumps.

 

[aet1]

I do wonder if having any thermostats on radiators is worth while - unless all the interior doors are kept closed.