Boiler lockout

[lambo75]

My Worcester 24i combi boiler thermal lockout switch activated for the first time today. I've traced the cause down to the pump not working and thus the central heating overheating. I've tested the pump, it works perfectly. There's no power supply to it from the PCB. The installation manual says check the flow switch, which again is fine. Does this leave the PCB as the likely fault? The boiler supplies hot water without overheating.

Any help greatly appreciated.

 

[clf-gas]

Check connections to the board, check output from the board, finally be prepared to replace the board less you can repair it.