baxi 105he ch fault

[TM37]

Hi all, I went to look at the above boiler earlier regarding a ch fault. The heating all heats up ok but the neons do not go past 50 degrees on the fascia. The boiler cools down then fires up ok but wont go over 50. I changed the ch thermistor but it made no difference. I checked the return filter which was clear so im thinking a board fault. The hw side works fine. Any ideas would be great! Thanks

 

[gas112]

has the board been changed in the past.
Check the temp knobs have full movement on them from min to high if not they board needs removing to locate the stat knob spindles correctly

 

[dcawkwell]

I'd say it isn't modulating and is ticking over on min burner or near to.