Radiator (and boiler) drain valve keys?

[pe2dave]

My 5mm across flats rad bleed valve key does not fit a bleed valve beneath the boiler (to drain off excess water in system).
It's either 6 or 7mm.
Anyone know what these .... bleed / drain valves are called and where I might find a suitable key please?

 

[Distinterior]

Here you go Dave.....This is what you need.
Although it says it's for opening cabinets for service access, it also has a square keys on it as well......
I have one and the 2 x square keys are 6mm & 8mm across the flats.

https://www.screwfix.com/p/3-way-services-cabinet-key/16428

 

[Bingy man]

My 5mm across flats rad bleed valve key does not fit a bleed valve beneath the boiler (to drain off excess water in system).
It's either 6 or 7mm.
Anyone know what these .... bleed / drain valves are called and where I might find a suitable key please?

It depends on the boiler make i e Worcester Bosch or valiant or god forbid one of the generic cheapo boilers out there. My advise is to drain from a radiator drain off valve or the bleed point as it’s common for the valves on the boiler to leak once touched . Have a look also at all the radiator valves on the ground floor as some have combined drain offs which use the bleed key to undo - these often have a white plastic cap small than a screw cover . Otherwise a small adjustable spanner will work ( ex gas mon)

 

[Bingy man]

Here you go Dave.....This is what you need.
Although it says it's for opening cabinets for service access, it also has a square keys on it as well......
I have one and the 2 x square keys are 6mm & 8mm across the flats.

https://www.screwfix.com/p/3-way-services-cabinet-key/16428

This might do the job but they are typically for gas / electric meter boxes and also lock shield valves-worth having in your toolbox tho..

 

[Distinterior]

This might do the job but they are typically for gas / electric meter boxes and also lock shield valves-worth having in your toolbox tho..

Yes,...It does have the triangular key that is found on gas/electric meter boxes but mine also has the 2 square keys on it.

 

[pe2dave]

It depends on the boiler make i e Worcester Bosch or valiant or god forbid one of the generic cheapo boilers out there. My advise is to drain from a radiator drain off valve or the bleed point as it’s common for the valves on the boiler to leak once touched . Have a look also at all the radiator valves on the ground floor as some have combined drain offs which use the bleed key to undo - these often have a white plastic cap small than a screw cover . Otherwise a small adjustable spanner will work ( ex gas mon)

Accurate as I can measure it it's 1/4"? slack 7mm - 3BA is tiny bit loose (but works). 6mm won't fit?
Vaillant boiler.
I've lost 1 bar (was too high,dripping outside) using molegrips?
I *think* the key is the same as for a rad drain valve (not bleed)... but I could be wrong.
Thanks gents, 6 and 8mm oddly sounds as if it would be either side?
I think a bleed valve is 5mm.
I can see why plumbing is a real 'trade'
========== Edit ====================
Yes, I could drain from a rad, but the boiler is 18" from / above my sink (i.e. convenient).

 

[Bingy man]

My 5mm across flats rad bleed valve key does not fit a bleed valve beneath the boiler (to drain off excess water in system).
It's either 6 or 7mm.
Anyone know what these .... bleed / drain valves are called and where I might find a suitable key please?

Send a pic of the valve as they can also vary in size depending on type

 

[Bingy man]

Accurate as I can measure it it's 1/4"? slack 7mm - 3BA is tiny bit loose (but works). 6mm won't fit?
Vaillant boiler.
I've lost 1 bar (was too high,dripping outside) using molegrips?
I *think* the key is the same as for a rad drain valve (not bleed)... but I could be wrong.
Thanks gents, 6 and 8mm oddly sounds as if it would be either side?
I think a bleed valve is 5mm.
I can see why plumbing is a real 'trade'

It’s starting to sound like you may have an issue with your boiler, dropping from o/flow o/side tells me the pressure has risen to + 3 bar and the safety valve has opened-hence the dripping. Try to get the boiler pressure down to 1.2bar and let it run up to temp -( heating) keep checking the pressure gauge and your looking for a sudden rise in pressure. if your pressure is above 2 bar after 15-20 mins you have a problem -if it’s between 1.5 and around 2 bar it’s probably ok and it could just be the safety valve passing-= pressure loss. Hope you can follow this and it helps ..

 

[pe2dave]

Send a pic of the valve as they can also vary in size depending on type

I can hardly get at it. Bottom of boiler 18" off worktop?
key is square, 6.14mm as accurately as I can measure it?

 

[pe2dave]

It’s starting to sound like you may have an issue with your boiler, dropping from o/flow o/side tells me the pressure has risen to + 3 bar and the safety valve has opened-hence the dripping. Try to get the boiler pressure down to 1.2bar and let it run up to temp -( heating) keep checking the pressure gauge and your looking for a sudden rise in pressure. if your pressure is above 2 bar after 15-20 mins you have a problem -if it’s between 1.5 and around 2 bar it’s probably ok and it could just be the safety valve passing-= pressure loss. Hope you can follow this and it helps ..

Agree with your symptoms.
1. At boiler service, we dropped pressure to 1.8bar from 2.1
2. Within a week it was back to 2.2 bar.
3. I dropped it back to 1.7bar.
"Range" supposed to be 1-2bar.

I think the source (guess?) the input, inline valve (90 turny thing) is leaking, letting mains pressure into heating water?
Plumber 'busy', will let me know when he can fit me in!

 

[pe2dave]

Send a pic of the valve as they can also vary in size depending on type

As you can see, it's a simple sq brass nut?

 

[Bingy man]

As you can see, it's a simple sq brass nut?

Yes I got you ,, I’d only attempt to drain from there if there are no other more accessible drain valves- if older type property it’s not uncommon to find one outside the property at low level , if no choice but to use boiler valve turn gently, maybe an imperial spanner will make the difference. Brass is soft and easy to round over or worse snap off if seized good luck .

 

[Bingy man]

Oh and btw 1.2 to 1.5bar is more than enough pressure. Pressure will rise as heating is used but should not rise rapidly over a short time. With a setting of 1.2 b I’d expect it to reach up to 2bar which is quite normal in the dead of winter. Another way to reduce pressure is to bleed rads. Releasing air will reduce the pressure.

 

[Daniel2]

Oh and btw 1.2 to 1.5bar is more than enough pressure. Pressure will rise as heating is used but should not rise rapidly over a short time. With a setting of 1.2 b I’d expect it to reach up to 2bar which is quite normal in the dead of winter. Another way to reduce pressure is to bleed rads. Releasing air will reduce the pressure.

Sorry, but I would beg to differ.

 

[Bingy man]

Sorry, but I would beg to differ.

Not sure which part you disagree with but my advice is based on my own experiences over many years. I’m not saying this applies to every boiler and every type of system but on many it does .

 

[chris.s]

dripping outside and variable pressures are symptoms that you have lost the pressure in the expansion tank you need to get the pressure out of the system and with a vent open repressurise the air side of the expansion tank to 2/3 running pressure

 

[Steve_Scott]

Seems you have to first establish why you have increasing pressure.

seems to me your possibilities are either:

1) your filling loop is letting by, or;
2) your pressure is increasing as a result of inability to accommodate thermal expansion.

By Regs, your filling loop shouldn’t be connected unless filling the system but everyone ignores this. Disconnect the loop and see if the valve is letting by when closed. Replace if needed.

Properly diagnosing an expansion vessel failure is less straightforward but when the system is cold, get the pressure to around 1.2 bar (assuming two storey house), make sure the rads are bled (any air in them will act as expansion space), then turn the heating on full whack (some boilers have a service/test mode that forces full heat). Keep and eye on the pressure gauge and see what happens once the system is up to temperature. If it rises by any more than a few tenths of a bar you likely have either a failed or depleted expansion vessel. At this point you should call a gas engineer as you’ll have to gain access to the boiler internals (unless you have an external vessel). Either way you have to drain down the boiler/system to establish if the vessel can take more charge or if the diaphragm/bladder has failed… honestly, it’s probably easier to just get a new one than diagnose the fault, and if it’s old (5+ years), I’d certainly swap it anyway.

 

[pe2dave]

Here you go Dave.....This is what you need.
Although it says it's for opening cabinets for service access, it also has a square keys on it as well......
I have one and the 2 x square keys are 6mm & 8mm across the flats.

https://www.screwfix.com/p/3-way-services-cabinet-key/16428

I doubt I can get this one in the available space, thanks though.
I'm looking for the grandfather clock type key?

==============

Lots of asides - all I want is a source of an appropriate key.

 

[pe2dave]

Seems you have to first establish why you have increasing pressure.

seems to me your possibilities are either:

I'll leave that to the plumber Steve, all I'm after is a key to adjust the pressure.

 

[chris.s]

https://www.amazon.co.uk/gohantee-Ratchet-Wrench-Service-Refrigeration/dp/B07TGC3D1T