heating coming whenever hot water used

bigjluk

as in the title ,my heating keeps coming on anytime a hot water tap is run from anywhere in the house.i also have a gas mains fed shower if this is anything to do with it,any advice would be appreciated.
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suse*

Is it a combi boiler? Do you mean the radiators get warm or just you hear the boiler making noises. If it is just making noises it will just be heating up your hot water that your using if your radiators aren't coming on as well.

bigjluk

Yes its a combi,and yes the radiators get warm

SGM1

It will be the diverter valve on the boiler letting by. Not much you can do apart from call someone to fix

macman

I don't think your shower is 'gas'. It runs on the hot water produced on demand from the combi.
Agree with SGM1, classic sign of a sticking divertor valve. There should be no flow to the CH circuit when the DHW circuit is calling for heat.