my baxi solo 3 PFL honeywell printed circuit board ,tells pump to run with no demand on s/v terminal (HEATING-H/WATER) this is the 2nd pcb which has lasted app 20 months. manufactuses not helpful and want me to buy another board (£140),changed overrun capacitor £6 but as I thought didn't work

derrick, February 2008

I'm suffering the same problem. It seems that the on-board relay contacts are 'welding closed' so pump runs on after time-out. i.e. relay undersized. Proof is that if you tap the underside of the control unit after time-out, the relay drops out and the pump stops. Suspect the only long term fix is to add a larger interposing relay with more robust contacts. I haven't tried this yet.

Steve Clayton, February 2008