Some radiators getting warm with heating off?

Graeme1978uk

Hi all,

We moved into a new build property in November and have noticed an issue with the heating. I think it may have probably always been like this but it’s only now we are into warmer weather we’ve realised.

The house is over 3 floors, we have a boiler downstairs and hot water cylinder on the middle floor. What we’ve noticed this week is that even with the temperature showing higher than the thermostat is set, when the water is being heated we are getting a couple of radiators warming up which isn’t ideal given how hot it’s been.

Everything here is under developer warranty, and we will report it today but wondered if anyone knew what the cause might be or if there was a quick DIY fix?

Inside the hot water cylinder cupboard I can see 3 x Honeywell valves which are all set in the ‘Auto’ position.

Any ideas what the cause might be?

Grenage

The valves are the most likely cause; are you able to freely move them manually from one side to the other?

They do often seize after time but it seems unlikely in a new build.

Jeepers_Creepers

Graeme, there are three valves? In which case that would suggest one for the hot water cylinder, and two for separate zones of radiators.

Is that the case? Do you have two wall thermostats?

Which rads are heating up? Are they close to each other? Are they both in the same CH 'zone'?

As Grenage suggest, a good first test on the valves is to (1) make sure nothing is calling for heat - not the hot cylinder, and neither of the two rad zones - simplest thing is to turn off the main power to the boiler. (2) check the lever on each valve - it should be sitting firmly against the 'auto' end. (3) gently-but-firmly move each lever to the far other end - it'll make a whirr sound as it does. Does it move smoothly (although against a spring pressure)? (4) Now release the lever (making sure it hasn't become held in the 'barb' on the slot side) and it should whirrr smoothly back to 'auto' - taking something like 2 or 3 seconds.

Report back please.

Basically, tho', it sounds like some 'let-by', where the boiler's water is going where it shouldn't. Good chance it's one of the two CH valves which is leaking a teeny bit. If it is, the choice is to have it replaced or - if it doesn't get worse - shut off the offending rads during Summer.

KnownMaynard

We had a similar house to you before, also a new build. There were two heating zones for central heating, so as suggested it's worth checking settings on both. A neighbour of ours over the road had issues with heating and hot water not being fully independent (I forget the detail) but it turned out their controller had been wired in incorrectly. Presumably the fact you are in warranty should mean it gets fixed quickly and without cost to you (our neighbours only discovered it after their two years were up).

Graeme1978uk

Thanks for the detailed response @Jeepers_Creepers and sorry for taking ages to reply.

The valves all appear to be operating normally. I reported the issue to David Wilson Homes and the plumbers tendered to fit these properties have been back out and accepted there are one or more errors in the pipework under the floors. We’ve got 7 of 16 radiators affected. Just waiting down them to book us back in to come and rectify the issue which unfortunately will result in some carpets and floors coming up.

Jeepers_Creepers

Good result, Graeme, and thanks for the update.