Hi . the pump might have seized. You may be able to get it going temporarily by opening the bleed screw and spinning the shaft with a cross head screwdriver. Water may squirt out , if it's a lot then you may have to take the pressure down a little by bleed it from ba rad
i've tried that and hot water is working ok, but still cuts in central heating mode, does d27 mean anything, that was on the clock display when i tried it the first time
Ok , it could be the heating stat, but give me a couple of minutes to check the fault code, thanks
Ok , can't find that fault code in the manual , but it could be the diverter valve is not switching over to beating . are you able to check that heat is travelling down the heating pipoes before the boiler cuts out. The diverter valve could be stuck in hot water mode
the outlet pipe from boiler gets warm before the boiler cuts out, but does not reach rads
Ok . the divereter is most klikely stuck on hot water and needs replacing . if you check the diverter valve when central heating on the pin should move out to the heating switch . the burner seems to be coming on for heating but can't get to the rads so is overheating
i have just checked the diverter valve and that is ok, not stuck, i used a small screw driver to push the switch in and the heating came on but cut out again after a few seconds
Is the burner lighting , for a few seconds before shutting down?
Well then that leaves the thermistors, these can be tested on ohms with a multi Meter.
thanks for all you help toby, i'll see if i can find someone local and hopefully reliable aswell, thanks again