TRV lifetimes.

[Andy Champ]

I've just been to visit my son, and found the TRVs in his flat completely stuck. I'm sure it's no coincidence that of the 5 rads, two had odd TRVs and worked fine, and of the three of the same (presumably original) type two had stuck wide open. However.... judicious use of an Engineer's Adjuster unstuck the little pin in the valve, so I didn't have to mess around with draining a system that's 3 hours from my home (and my wet-and-dry vac, I haven't forgotten that trick). One of the tops disintegrated, so I had to get a new valve - carefully picked for a compatible top :).

Anyway the point of the question is - now I've thumped them and got them to behave, are they likely to go wrong again soon? Should I aim to swap the lot out next time I'm up there?

Andy

(and another little story... as I logged in, aiming to type this up, I noticed there was a noise of running water. Odd... doesn't seem to be going anywhere... ah well, she just had a shower... odd... still running... B****y valve on the main coldwater tank has stuck wide open, it's spraying over the side of the tank, made a puddle on top of the ceiling - and I wanted an early night. S** it, stopcock off, mop up ceiling, job for tomorrow.)

[Andy Hall]

They may do or they may not. 7 years is often mentioned for TRV lifetimes - generally based on what happens to the wax arrangement in the head.

I've always used Drayton (Invensys) TRV4s. This is over about 30 years and in different houses. I don't believe that I have ever had less than 15 years life out of one.

I do also take care to ensure that the system is kept clean and topped up with inhibitor and have never had a stuck valve as far as I can remember.

I think it's likely that when the mechanism sticks for any length of time, it screws up the thermostat mechanism in the head.

At any rate, if you are going to change a couple of TRVs, then in a population of 5, it's far better to change the lot for TRV4s (don't be tempted to buy cheap junk), and while you are at it to clean out the system. It's the perfect opportunity to clean out any sludge and to fill the system with a good quality inhibitor such as Fernox or Sentinel.

That one is best resolved by making sure that the pipework is well flushed out and replacing the valve with a Torbeck type.

[bof]

I've just had the head fail in one (a Pegler Terrier II) after about

18months, I was going to buy another identical one and just use the top, anyone any comments before I do?

[Clive Page]

In message , Andy Hall writes

Interesting - I was thinking of starting a thread asking which brands were reliable. Also saying that I wasn't going to get Drayton ones again because about 3 of mine have stuck and need to be replaced. But I think they are all over 15 years old, so maybe that's not too bad.

What surprised me browsing the local merchants is the huge range of prices, from under 5 pounds to something like 30. Does anyone know if the expensive ones are likely to last longer?

[Bob Mannix]

IMHO Drayton TRV4's are the dog's b*ll*cks of TRV's (and are quite visually attractive) and are not the cheapest. I suspect you get what you pay for!

[Andy Wade]

Danfoss.

[Andy Hall]

I think that that's very reasonable.

I would shop around and get a good price on a complete set of TRV4s and change the lot in one hit. Then forget it for the next 15 years.

[Andy Champ]

That seems to be fine. It's only the valve bit that's stuck. Must phone him and check it's all working OK.

My tank BTW was the fibre washer disintegrating (20 odd years old) and I just happen to have a spare one which came off the CH header tank after I replaced it because it kept overflowing - which turned out to be a leaky coil.

Andy