Potterton Prima 40F - Takes a long time to fire up, apart from if I hit the front panel!

[Tel]

Hi,

I have an old Potterton Prima 40F in my house, which I'm guessing is 10-20 years old.

When I moved into the property in the winter of 2014, I had the same fault as I've seen tonight.

I can hear a click, the boiler fan starts up and then a click and the fan stops. This repeats again and again. I've read a lot of the times it's the PCB.
At the time I got a gas engineer out, told him what I had seen on forums etc but left him to investigate. He said it was the fan.
Replaced the fan and it did work a little better, but the fault has still been there, although it might have only taken 5 attempts to fire up in the past.

Now there is a fix to this, when it's mid fire up, if I hit the front panel near the flame window, it fires up pretty much all the time. (Video at the bottom)

Tonight I let it run for 15 minutes and it didn't fire up at all, I hit the panel on the next ignition and it worked.

I've just let it run naturally and after 25 minutes, it did fire up on it own.

I would say the fault has always been there since I moved in, but in the past only taken 10 fire ups maximum to kick in.

Video (You might need to click sound on)

Imgur

Any ideas? Could it be something in the ignition, electrode area?

Thanks for any assistance

 

[townfanjon]

You remind me of the Fonz ( happy days , sorry if you are too young to understand) belting the juke box to get free songs .

Come on pal , you shouldnt have to thump a boiler to get it to work , get a GS reg guy to take a look .