Potterton Profile 60e - starting and stopping

Hi, I have a problem where my potterton profile 60e bolier ignites and heats up normally for about 10 - 15 mins. Thereafter the boiler cuts out and makes a sound as if misfiring or trying to ignite up, the pilot light remains on throughout, the boiler seems to try and start up every few seconds in a cyclical fashion. After a few mins the boiler sparks up fine to produce the flame.

- This sounds similar to the issue on //www.diynot.com/forums/viewtopic.php?p=49729 where 'namsag' diagnosed it as a solenoid issue.

- Or could this be something overheating causing the boiler to cut out and the igniting and flaming up when cooler?

The CH and HW seems to be working okay but the noise indicates something isn't quite right and I don't want to face any nasty surprises in the future given I've a young daughter.

I want to diagnose what the issue is EXACTLY as far as possible, as I've spent a fair amount of money last yr (new pump, system flush) and can't afford to throw much more money at the heating system as I've been made redundant and have a wee 9 month old with cold hands!

Admittedly it hasn't been serviced in years.

Appreciate any assistance on the issue and a rough assessment of likely costs!

Otherwise anyone around the NW London are welcome to pop in for a cuppa, biccies and a looksie!

Thanks in advance.

Harry Potterton.

Sounds like it could be the PCB, have seen a few Profile/Prima boilers that attempt to start as as soon as the fan triggers the air pressure switch the PCB starts the ignition sequence again, the pilot light should not remain lit all the time. It could be a solenoid problem, try swapping the solenoid coils to see if this makes any difference.

It sounds as though that there maybe flame recification issues. Why ignore servicing on the appliance? Although this boiler has no perm. pilot, the injector could now be partially blocked (another neglected boiler issue).

If its over heating you have to depress the butto underneath the boiler to reset.

Namsag has a valid point aswell.

Dave

New PCB should sort this problem

just check the white connecter on the pcb . vibration can cause it to move.The overheat stat pushes on it as you raise the pcb cover back up.

Okay, so I'm going to attempt the re-soldering efforts outlined in http://kaijaks.co.uk/blog/nick/2008/02/10/dodgy-old-boiler

I wanted to remove the PCB, only issue is how do I ensure I have turned the whole boiler system off before opening up the cover?

I cannot see the boiler plugged into a socket so am assuming it's wired up. The fact that the pilot light is permenantly on is worrying.

I think the steps would be to:

1. Set boiler thermostat to 0 position
2. Flick the the CH & HW switches to off position.
3. Turn the gas off at the mains (ie: pull the metal lever a quarter way down)
4. Turn off the mains electricity for the house at the main fuse box.

Can anyone confirm? I need to get the PCB out asap as a friend will do the solder work...hence why I'm up at this time!