Potterton Prima 30f

[JE-P&H]

I've got a Potterton Prima 30f that will only fire with the case off. I have stripped and cleaned everything burner, flue heat ex etc. it's obviously a air flow problem but not sure what? Could it be a lazy fan? Anyone know how to test the fan on these? With case on flame goes out after about 20secs then relights any help would be appreciated!

 

[Killy Bing]

Aps switch hoses stiff?
slow running fan or aps sounds goosed to moi

failing that pcb maybe

the more experienced guys will have a better idea, ive only worked on 4 by my larry

 

[Millsy 82]

Check the flue. These are prone to rotting causing the flame to lift. You can get a flue remedial kit for it just slots over the inner flue.

 

[JE-P&H]

Thanks for the input guys, I have tried changing APS no change. Closer inspection and there does seem to be a slight rotting of the inner flue so I have ordered a remedial kit! Thanks for the heads up easy when you know what your looking for. I did speak to Potterton and there was no mention of the flue rotting at all let lone it being a common fault!

 

[zeebeedee]

Never seen the flue rot cause this and I've seen a lot. Is the pilot lighting and clicking away?

 

[Millsy 82]

I've seen loads. I must have 3-400 boilers on the patch I cover loads need flues and if you gag them it will go off the scale. Have a load of alpha cd range that have the same kind of problem but the flue turns brittle and cracks.

 

[zeebeedee]

I've seen loads. I must have 3-400 boilers on the patch I cover loads need flues and if you gag them it will go off the scale. Have a load of alpha cd range that have the same kind of problem but the flue turns brittle and cracks.

Seen loads of rotten flues but never seen it cause this fault. If the pilots lighting but clicking away, it's either aps or board, or sometimes the tubes to the aps.

 

[JE-P&H]

Pilot lights, main burner lights stays lit for 20seconds clicks off, lights again, clicks off and keeps going like that. Take the case off work perfectly! Il try the flue kit tomorrow if that doesn't sort it that it then back to the drawing board

 

[Millsy 82]

Seen loads of rotten flues but never seen it cause this fault. If the pilots lighting but clicking away, it's either aps or board, or sometimes the tubes to the aps.

From what I read it's not just the pilot it fires on main flame for 20 secs. And it runs with out casing on. So to me first place to look is flue.

If I have read it wrong sorry but if the flue is starting to rot it needs replacing anyway.

 

[Millsy 82]

Pilot lights, main burner lights stays lit for 20seconds clicks off, lights again, clicks off and keeps going like that. Take the case off work perfectly! Il try the flue kit tomorrow if that doesn't sort it that it then back to the drawing board

What was the flame like? Was it bouncing around or a steady flame?

 

[JE-P&H]

I wouldn't say it was steady so ye bouncing is probably a good way to describe it!

 

[zeebeedee]

I wouldn't say it was steady so ye bouncing is probably a good way to describe it!

Does the pilot light with the case on?

 

[zeebeedee]

From what I read it's not just the pilot it fires on main flame for 20 secs. And it runs with out casing on. So to me first place to look is flue.

If I have read it wrong sorry but if the flue is starting to rot it needs replacing anyway.

Defo, but I'm not 100% that will solve it, they light with rotten flues just has a dancing blue flame picture.

 

[JE-P&H]

Does the pilot light with the case on?

Ye it does what I explained above with the case on. Case off works fine doesn't cut out etc.

From what I read it's not just the pilot it fires on main flame for 20 secs. And it runs with out casing on. So to me first place to look is flue.


If I have read it wrong sorry but if the flue is starting to rot it needs replacing anyway.

This was exactly my thoughts, with case on must be a problem with air flow into boiler so check flue was clear etc. But after it was mentioned here they were prone to rotting I double checked and there were small signs. As it work s fine with case off surely that's rules out PCB etc? My thought is either Flue, fan or APS?

 

[zeebeedee]

Would rule out pcb, change the aps tubes and injector if its still causing problems

 

[Ermintrude]

My money is on tubes / fan aps conn. Or fan

 

[Millsy 82]

If the flue is rotten enough it will do exactly what the op is saying. Or high burner pressure can cause it as well. That would be the first 2 things I would check

 

[JE-P&H]

If the flue is rotten enough it will do exactly what the op is saying. Or high burner pressure can cause it as well. That would be the first 2 things I would check

I hope so, burner pressure is fine 8mb MI's asking for 8.4mb

 

[JE-P&H]

Remedial kit fitted and working perfectly now I will put that one down to experience!

 

[bright spark]

I had a weird problem like that before. The boiler would run for a short period then stop, but would run fine with the casing lid off. Wasn't any of the above. It ended up that the boiler was partially blocked on the gas side. The heat exchangers cast iron with small gaps between the 'fins' on it. Well the one I had the prob with had. I had to run a junior hacksaw blade up in the gaps. The boiler was undersized for the property and ran for long periods. Maybe yours is the same. All the best.