Another failed TRV

[ppppenguin]

When I moved here in 1998 I overhauled the central heating system. Actually almost a new installation. All that was left of the old was the boiler (since replaced in 2011) 3 radiators (out of 14) and a few pipe runs. I used Drayton TRV4 thermostatic valves as they are meant to be the best available. https://www.screwfix.com/p/drayton-trv4-...mm-x/26100 They're not cheap, £30 now, though rather less back then.

I've just had the 3rd valve body failure. I've also had 3 or 4 heads fail, with crumbling plastic. I can't say I'm happy. When the last valve body failed I decided that £30 was a bit rich so I decided to use a Peglers valve:
https://www.screwfix.com/p/terrier-3-whi...tid=225690
I've used quite a few Peglers products and the quality has always been first class.  That TRV is only about a year old so too soon to say about reliabilty but it feels better made than the Drayton. Smoother action, not so prone to making odd noises when almost closed. Pegler do a more expensive TRV with liquid thermostat element but the wax one seems fine.

I've ordered another Peglers valve to collect tomorrow morning. Then the usual faff of turning off lots of other rads, depressurising the system, replacing the valve, repressurising, rads back on. I turn off other rads to minimise loss of treated water.

I suspect this won't be the last time I do this. I could replace all the Draytons as a precaution but that's a fair bit of money and effort. So it will be one at a time and cursing on each occasion.

[peter scott]

We have just recently fitted three Danfoss valves and in the short time we've had them I'm quite impressed. They appear to be less "digital" than most TRVs I've used and the lock-shield valve that comes with them is rather nice too. Not the usual thing with a plastic hat on. The cover is a proper chromed hex thing concealing a nice Allen key socket.

Peter

[ppppenguin]

Cheaper than the Peglers too, and it includes a lockshield. Danfoss are meant to be a good make. But so were Drayton.

[Cleggy]

It seems that old, traditional "big" names may not mean so much now. I specifically bought an "MK" ceiling switch for the bathroom recently, but was disappointed to see it was made in China. Now, the Chinese make some fine stuff, but they also make a lot of bargain-basement stuff. How "MK China" compares with "MK traditional" remains to be seen.

[Refugee]

I once used one of those ceiling switches for a strip light with an iron choke.
It used to spit and pop especially when switching off.

[Radio Fixer]

I had never bothered with TRV's until a few years ago when a friend told me how wonderful they were.
Fitted Drayton fortunately not everywhere. Heads get broken off far too easy. Tried to find a perforated guard to protect them but failed. Certainly take them off if having workman in.

They come with chrome caps that can turn them back into manual valves and thats how I have left them. Certainly not going to drain down to replace rubbish items.

Gary

[ppppenguin]

If you have to remove a rad for decorating always use the plastic cap instead of the thermostat head. Otherwise one cold night and you might get a flood. If you can't find the cap, a small metal disc (5p?) between the head and valve should do it.

You don't need to drain down to replace the valve bodies. Just ensure there is no other open water path to either side of the valve. The rad side is easy, just turn off the lockshield on that rad. I turn off all valves elsewhere to isolate all other rads from the system. Also the valves that isolate the boiler. This minimises water loss when depressurising. If you have an open system then you need to plug the fill and vent pipes.

I probably lost less than a teaspoon of water when I did the valve this morning. Plus a few desert spoons full when I beld off the excess pressure.

[Radio Fixer]

You have obviously got the knack Jeffery.  I know you can easily replace the valve bodies but is there any point?  One knock and it doesnt have to be hard and it needs another one.  If I were to replace them it would be with something else (maybe Pegler as you went for) hence then water messing about with.

So just use them as manual valves and forget it  

Gary

[ppppenguin]

Gary, I think you've misunderstood what I meant by valve body. The body is the metal bit with water flowing though it. Changing that as I've just done is a rigmarole as I've described. The head is the thermostat, the vulnerable bit that's also easy to change. Changing to a different make of valve I'm obviously replacing both the body and the head. The Peglrs head looks less vulnerable to knocks than the Drayton.

Without TRVs it's more or less impossible to make my heating work sensibly. For example as the sun moves round the house different rooms get solar gain and the TRVs regulate the radiators accordingly. They also automatically adjust to warmer and cooler days.

I could use a central thermostat and have done in the past in other houses. The result is that the temperature is always wrong in most parts of the house.

[boater sam]

If they do make a noise they are possibly on the wrong end of the radiator. Should be on the flow. They are not bidirectional valves.

Danfoss are prone to the diaphragm sticking closed if not used for a long time.
All valves are subject to damage if misused, i.e. knocked.

You won't go far wrong with Peglers.