TRV started to leak

frankersBri

The TRV on one of my downstairs radiators has started to leak. It was installed 2 years ago as part of some renovations, and have never had any problems. 

Noticed small puddle this morning. From feeling around it, it seems like the leak is coming out of the bottom of the top-most silver part of the valve, the larger bit with the vertical grip/tread/notches. 

Any ideas of steps I can take to address the problem, without draining the system and replacing/attempting a fix?

BUFF

it's probably leaking from around the spindle. if you take the sensor head off (set it to max & then unscrew the knurled nut, it will just lift off) you should be able to see.

stuhse

Tighten the two nuts you can see.  By far most likely thing, one of them just needs a nip.

ThisIsWeird

FBri, first thing is to find out where the drip is coming from. So, wipe with kitchen towel, and shine a light on it.

Chances are that the valve itself is fine, so it'll be one of the larger nuts that connect it. 

Confirm, please, and report back. 

Solution should be 'easy', depending on tools...

locky123

I've got these TRVs and some started leaking after many years from the spindle which is adjusted when the TRV is twisted and moves the spindle. If you turn the TRV to highest settings then you can remove it and you may find water underneath the TRV head where the spindle protrudes. I think this leak may occur if they are not frequently adjusted. You may find that this spindle leak stops if you leave it on highest setting. The only reliable solution is to replace the complete TRV which is a Drayton R212. You can get replacement gland seals but not had any success after replacing. It could be leaking from the compression joint below the TRV, usually the leak leaves a stain/residue which may help point to the leak source.  If it is this then tighten the nut a little to increase the compression. I've never felt that TRVs actually are a significant benefit in our house. 3 out of 10 R212 TRV have leaked after 10+ years.

BUFF

locky123 said:

3 out of 10 R212 TRV have leaked after 10+ years.

I have 7 TRVs (not Drayton 212s) & not 1 has leaked in 30 years ...

frankersBri

Thanks all. When I take the big plastic bit off, it looks as though there has been some leaking for some time. Turning the valve off has lead to no further leaks. May turn it back on and see what happens.

ThisIsWeird

Ok, it's from around the 'pin', the bit that's pushed down by the head in order to control the valve.

Underneath the white plastic nut will likely be a rubber washer through which the pin passes, and this is meant to keep the water out, whilst still allowing the pin to move smoothly.

Can you turn that white nut with a spanner? Before trying, mark a dot on its side so's you know the starting point. Then I'd try a clockwise 1/64th turn - a tweak - just to check there's movement there, and this should also stop any leak. However, it will also possibly make the pin up/down movement stiff, so - after checking you do have that 'tweak' available to you, I'd then slacken it off a good half turn or more (might start to drip) and smear the pin with silicone grease. Then push the pin down firmly until it bottoms-out with a gentle clunk, allow it to pop back up, repeat, wiping the sili-g on it, until you have a well-lubed pin. 

Finally tweak the plastic nut up to the original position, plus a tiny extra tweak. Check it ain't dripping, and that the pin remains easy to push down.

Chickereeeee

I have replaced a trv successfully using the 'freeze pipe' method - you have to drain down the radiator, but not the whole system. Using a kit like this (just an example):

https://www.screwfix.com/p/arctic-products-pipe-freezing-kit-150ml/433fj