Potterton Prima f60 problems

[mackfly]

I have a Potterton Prima f60. It tries to start with the fan going for a few seconds and then powers down. I've had someone in but they couldn't spend much time on it due to prior jobs. They tried the PCB but this didn't solve it. He suggested it may be the air pressure switch. I've since got it going by giving it a thump when the fan started up. This wasn't just out of frustration, this was suggested as a possible solution. Can anyone suggest what the problem is? I have very little faith it will start up again when on the timer.

 

[Rob]

The fan cycling on off is a PCB fault. Was it replaced with a brand new one out the box?

 

[mackfly]

He put a new one out of the box in but it did have any effect.

 

[ChrisR]

Either it was an old one (off ebay?) or he left a bad connection or it could be the fan/aps if the "few" seconds is longer - does the burnter light at all?

 

[frankthegasman]

this could also be the fan not running fast enough to open the aps or a faulty aps ,good luck

 

[twgas]

I'd check restrictor in air tube, although i put 3 new pcb's on a profile, to solve this prob, a few months ago - each new pcb was new and had same fault

 

[mackfly]

The unit seems to be working now. There has been a couple of mornings where it has failed to fire up with the fan just powering up for a few seconds and then nothing. If I give it a thump from underneath at this point it seems to catch hold and work.