worcester 24cdi hot water gose hot then cold then hot

[gtakarting]

Hi

Can anybody help please my 24cdi combi boiler when in the shower or just runing the hot water from a tap gose hot then cold over and over. if i stand next to the boiler when the hot tap is on it seem to be all ok until something clicks the flame light gose out then the boliler shuts down and restarts its self again.

Thanks Gareth

 

[ollski]

Probably look at the hot water sensor first, then check the hi and low settings on the gas valve, then the plate heat exchanger.

 

[bengasman]

typical symptoms of blocked plate hex.
run heating and check the bottom of all the rads; if they stay noticeably colder in the middle at the bottom than at the top, your system needs cleaning.
see faq for more info