Radiators heating when only hot water on

[annc]

We discovered a problem this morning which hasn't been noticed before. We do not have the central heating on but the boiler is programmed to come on for hot water only for two hours in the morning.

The boiler is situated downstairs, but pump, valves and hot water tank are upstairs. With only the hot water programmed to be on, not the central heating, the upstairs radiators are becoming hot.

Could anyone explain why this should be

Thanks

Ann

 

[Armo74]

Valve is probably stuck in mid-position. Or just letting by

 

[workingman1]

It may be because the return water from the cylinder is traveling down the heating return (rads) instead of the primary return(boiler).
If it is the case you will need to get this part of the cylinder repiped if the tees are in airing cupboard then shouldnt be to bad but if its under the floor its worse.
Is it a new install get who ever fitted it to come back and have a look

 

[Agile]

It may be because the return water from the cylinder is traveling down the heating return (rads) instead of the primary return(boiler).
If it is the case you will need to get this part of the cylinder repiped if the tees are in airing cupboard then shouldnt be to bad but if its under the floor its worse.

I dont see how pipework which has worked fine for several years could suddenly become incorrect!

 

[annc]

Thanks for replies - I am hoping that it is a valve - fingers crossed. Although it is a newish boiler, the system is about 25 years old - had new valves, pump, thermostat etc fitted at same time as boiler which was about 3 years ago.

Looks like I will have to call someone out come Wednesday. That's the bit I really hate - just wish I could find someone reliable

 

[HERTS P&D]

Was it power flushed at the time of fitting the new boiler?

My guess is that some debris is stuck in the 2/3 port valve not letting it close.

Andy

 

[45yearsagasman]

Unless there has been recent pipework alterations to cause the reverse circulation referred to by workingman It will almost definitely be the zone valve passing. (very common fault)

 

[workingman1]

ha, you mock me Sirs,

I missed the bit where the op said it was an old system

Cheers

 

[annc]

Again - thanks very much for input. Just realised that we have a Home Emergency Service through our bank so called them out. They came this morning and the guy didn't seem too sure of what he was doing. He confirmed that it was the motorised valve letting by but said he would have to drain down the entire system. He was going on about this maybe affecting our solar panel etc (never has before). Said it would take several hours to do.

I am sure I have had this valve changed before without system being drained, but perhaps I am wrong. Can anyone confirm.

Thanks a lot.

Ann