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Plumbing

Changing radiator lockshield valve to TRV

Anonymous user 28/02/2024 - 3.32 PM

Hi, I'm looking to change a lockshield valve to a TRV on one of my radiators. I have a closed pressure heating system with underfloor heating on the first floor and radiators on the second floor. The radiator in question (on the second floor) has a lockshield on both ends (bottom left and top right of the radiator). I plan to replace the lockshield on the top right of the radiator with a bi-directional TRV. My question is, given the setup I have is there an easy way to achieve what I want without needing to drain the whole system? Can I just:- 1) switch off the heating system and the water supply to the system, 2) since the radiator in question is on the second floor and therefore one of the highest ones in the house and also the valve I want to replace is at the top of the radiator can I just de-pressure the system by slowly lossening the lockshield valve (with the help of old towels and a bucket to capture the water which comes out)? 3) then completely remove the lockshield valve in question and replace with TRV? Thanks

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2 Answers

H2Go Plumbing

Rating: 5 out of 5

Basildon

Hi Daz, Provided that there isn’t a large amount of pipework above this radiator and that the boiler itself is below the radiator level, what you are suggesting is perfectly possible, though it should be noted that because it is a pressurised system, there will still be a fair degree of water that will spray out at high pressure for anywhere between 15-60 seconds after the nuts on the fitting are fully loosened and the seal is broken depending on the amount of pressure that is currently in the system so it would be wise to have pleaty of towels on hand as it would be hard to catch most of the water with a bucket due to the nature of the job. I would bear in mind though that not all valves are the same, before starting the job, it is best to make sure that the new TRV is compatible with the current fitting in the radiator, otherwise that will need to be replaced as well.

Answered4 October 2017

T&M Plumbing and Heating Services

Rating: 5 out of 5

Truro

I strongly advise you not to attempt this at all. There are a lot of things that could go wrong and i would 100% get a qualified Plumbing engineer to do it. No matter what type of system you have you could end up damaging your property and a simple job for an engineer could turn into an expensive nightmare for you. i cant believe another engineer has suggested it would be ok to do so without draining.

Answered21 February 2018