Any boiler experts on? Boiler firing up for water but not for heating...

[Bettyhatesavocados]

Can anyone give any insight? It's not a combi. It's just a regular boiler. It's set to come on for water and the pilot light's coming on for that and the water's getting hot and the pilot light's then going out when it should. The heating's just put on as required (not often but would be needed more in the coming months) but when the slider is set to 'constant' to switch it on, the pilot light's not coming on/ firing up and the display shows a zero which means nothing is happening...
Anyone got any idea why the pilot light would come on for the water and heat it up but not for the heating? Seems weird. Any insight would be appreciated. Hoping it's nothing crazily expensive to repair.

Thanks!

Issue with diverter valve thing?

Is it triggered by a battery-operated thermostat? If so, maybe the batteries need replacing.

I had something similar. Apparently boilers have an internal thermostat if that goes wrong there’s not enough power to keep the temperature up enough to heat the water and keep radiators hot

You need a heating engineer

A problem with the valve, by the sounds of it. Time to call an engineer.

Absolutely not taking the piss, but have you checked nobody’s turned the thermostat down too low or to zero? It’s probably not the cause, but worth checking if you haven’t...

Thanks, everyone. No, the thermostat is ok and the batteries are fine. Looks like it's probably a heating engineer! It's weird if the valve is knackered as, while the water is timed to come on each day for a period, the heating is rarely used...unless it's freezing!
Oh, HeatherJayne1972, the weird thing is: if the water and heating are put on 'constant' the heating comes on too! But it won't come on independently!
Thanks everyone!

I recently had a valve issue with mine that did the same thing, it was v quick to fix but I live in an HA property so I've no idea of cost.

Happened to us last week . It was the pump . We had to get a new boiler . Ours was 18 years old though !!

We had this same issue.. we replaced the diverter valve which seemed to temporary fix the problem but then the pump went!