Warm radiators upstairs when hot water is on

foreversummer

Hi

I've just noticed that my upstairs radiators are warm when I just have my hot water switched on.

I do have TRVs on each one and I have turned them all to the fully open position for the summer as I am sure I have read this prevents them from sticking.

I suppose I could turn them off, or is there likely to be a problem that I need to fix?

I'm quite sure this never happened last year. Any advice greatly appreciated.

Foreversummer

kittykat500

Mine does this too! Although not sure if it's turned off - it's a pain in the neck when the weather is hot!!! Sorry to hijack your thread foreversummer.

foreversummer

Thats alright kittykat500. Glad I am not alone. Strange things seem to happen in my house!

Perhaps some knowledgeable person will be along to enlighten us soon!

Foreversummer

nickcardwell

i get that as well, nearest one near the hot water tank.

condunction heat?

Incisor

foreversummer wrote: »

Thats alright kittykat500. Glad I am not alone. Strange things seem to happen in my house!

Perhaps some knowledgeable person will be along to enlighten us soon!

Foreversummer

There is a known issue with divertor valve systems which requires the return from the hot water cylinder to be plumbed into the return pipe to the boiler after all radiator returns, otherwise there can be a flow via the returns of the radiators which are plumbed correctly to the flow side of the heating system [ie backwards] and thence via the radiators which are plumbed incorrectly back to the return side [ie forwards].

On gravity hot water and pumped radiator systems, you can get a gravity flow when the pump is off.

foreversummer

Thanks Incisor

Not sure I really understand as I am not familiar with the terms, but basically is it harmful? Do I need to do anything about it (apart from the obvious warm radiators on hot days are a bit of a pain)? and as I am quite sure it was not like it last summer has something gone wrong?

Sorry to sound so thick.

Foreversummer

Jonesya

Incisor wrote: »

On gravity hot water and pumped radiator systems, you can get a gravity flow when the pump is off.

Depends - some gravity systems have a check valve on the radiator loop to prevent gravity circulation. The valve on our system failed with the result described by the OP.

virgin_moneysaver

we're the same - got a combo boiler (no hot water tank ) summer setting on boiler, off switch is activated on remote control thermostat & there is still residual heat coming from rads

foreversummer

Does anyone know if the check valve is the same as the three way valve? I have a little silver box in my airing cupboard which I believe is the three way valve.

Foreversummer

kittykat500

"There is a known issue with divertor valve systems which requires the return from the hot water cylinder to be plumbed into the return pipe to the boiler after all radiator returns, otherwise there can be a flow via the returns of the radiators which are plumbed correctly to the flow side of the heating system [ie backwards] and thence via the radiators which are plumbed incorrectly back to the return side [ie forwards].

On gravity hot water and pumped radiator systems, you can get a gravity flow when the pump is off."

Wish I'd never asked - no offence - bit of a bimbo when it comes to plumbing!!

babyangel10

Another thread hijacker and fellow plumbing bimbo here!

I have just noticed that one of my rads is hot too, without the heating being on and boy did I panic?!!! I turned everything off, boiler, rads, hot water supply, shower pump etc etc!!! Had visions of a huge burst happening and hot water gushing out of everywhere!

All rads apart from the hot one in the bathroom were turned off at the TRV for the summer (had just forgotten to do it with the bathroom one) and so were cold. I have turned the bathroom one off now too so am hoping it doesn't happen again

I have a tank in the attic and an immersion heater jobby in the airing cupboard if it makes any difference?

So, to add to kittykat and foreversummer's concerns - should I be desperately worried or just a bit annoyed about the additional heat?

I did try to turn the red handwheel thingy in the airing cupboard that's marked 'CH' to see if it helped but it's seized :eek: (even though I turned it back half a turn years ago when I first moved here, as advised to do in many a DIY book!)

Any advice on how urgently this needs sorting much appreciated (where's 'Canucklehead' or 'Corgiguy' when you need them?!!! )