105He mystery

[Backboiler]

Went out to said boiler locking out on overheat fault code 30 and 40 degrees flashing. Checked overheat wires at PCB and got continuity. All pointed to PCB. Replaced PCB, ran boiler for half hour on Heat and HW; fine. Just packing away and locked out with same fault lights flashing. Called Baxi for help and went through all their suggestions but they were puzzled too. At this point it wouldn't reset. Lost connection to Baxi (funny how you lose connection when they are as flumoxed as we are). Still short circuit on overheat circuit at the PCB. I put the old PCB back in,and it fired up. I'm guessing dodgy wiring loom. The earth wire had been deformed by the hinged front panel. Does anyone know if an earth fault can cause this?

 

[Ermintrude]

Don't think earth fault can . But u may have other damaged wires. Inspect and test each and every one. O/H stat might be worth checking .... Loose connection?

 

[Backboiler]

Don't think earth fault can . But u may have other damaged wires. Inspect and test each and every one. O/H stat might be worth checking .... Loose connection?

Thanks....Dont think it can be the OH stat because I was getting short circuit back at the PCB for the O/H stat and flue O/H stat every time it locked out. Boiler is still working 4days after refitting the old PCB