Is there a circuit diagram available for a Baxi solo 3 PCB(231711)?

The central heating pump is supposed to continue to run for approx 8 minutes after the timed cycle to cool the heater matrix. In my case the pump runs continuously but if you tap the PCB it switches the pump off as it should. I have replaced the PCB and everything works fine but I would like a circuit diagram of the PCB if one is available to try to repair the original.