Potterton Profile Not Lighting

Had a call to look at a Potterton Profile today which was not working properly. The customer said that the hot water was only lukewarm and the boiler was lighting but not staying lit for long, or not lighting at all. When I arrived the fan was running, but the boiler was not lit or trying to light. I reset the thermostat and it lit without any trouble and continued to run. I reset the thermostat a couple of times and again it lit and ran as it should. I opened the case and looked inside the boiler but there didn't look as if there was any issues. I checked the burner pressure which was correct. I lowered the controls cover and made sure that the air pressure switch tubes were connected properly and not kinked. All of the electrical connections looked good to.

I put the boiler back together and as I was screwing the screw that holds the grey bottom cover on it started playing up. The boiler was running but cut out and the fan continued to run but did not try to light. As I moved the screw the boiler was cutting in and out, making a sort of juddering noise. The customer said it had been making this noise for months and assumed it was limescale. I lowered the controls cover again to and the boiler cut out again, moving the connections to the PCB I could see a small spark due to a poor connection. There was a dry joint on the longer multi plug at the connection of the brown wire. The brown wire connects to the air pressure switch which explains why the boiler was not always trying to fire when the fa n was running. I replaced the PCB to solve the problem.

Disclaimer: The works described in this blog are a record of work undertaken and should not be taken as guaranteed to solve your problem. Work should only be carried out by persons qualified and competent to do so.