potterton prima f 40 boiler

[g-tec]

i have a potterton prima f 40 boiler which fails to light . the flue fan starts then after a few seconds cuts off. the fan will then keep starting and stoping .i have renewed the flue pressure switch thinking that was faulty but the boiler is still doing the same. if i blow down the presure switch tube i can hear the switch clicking and the boiler will run for a few hours then stop again. ive checked the fan and the fan is working at full speed .
burners and igniter is working ok if i can get the flue fan to stay running.
any idea what to do next

 

[ollski]

clean the fan venturi

 

[corgigazza]

Common fault replace pcb.

 

[gazthepottertonengineer]

this is common fault but not always pcb that causes it definately try cleaning fan venturi and check hoses arent split or kinked anywhere

 

[ollski]

Also check that the flue isn't corroded, this will cause the boiler to attempt to reburn the flue gases and go out. common problem on the prima and there is a flue repair kit to sort it.

 

[just-thinking]

usually pcb.sorry nearly always pcb,but check for 240v on sw live-neutral.and perm l-neutral.

pcb last approx 7-9 years.

flue can corrode on these models.when boiler is running .with case on.watch flames through sight glass if flames are lifting off burner, flue is probaly corroded.holed or rotted away.
pott make a remideal flue kit for these boilers.

 

[B.O.B DOLE]

this is common fault but not always pcb that causes it definately try cleaning fan venturi and check hoses arent split or kinked anywhere

try a fan pressure test

 

[corgigazza]

The return air pressure hose has a restritor insert fitted just a above the aps, the hole in this sometimes blocks up, hole only about .5mm diameter and difficult to unblock, hrpc supply new ones quite cheap.

 

[corgi del]

I had one of these these yesterday. Very unlikely pcb. It is good practice to always change hoses when you replace APS. If it is the pcb the burner will die before APS clicks off.

 

[bab]

If the restricter is semi blocked it can cause the very simptons u r getting try cleaning this first ,found this problem a few times.small brass fitting in the clear tube on the air presure switch.

 

[ChrisR]

I thnk I've changed about 25 pcb's to two or three fan/aps/hose/brass restrictor problems. The air related stuff was much slower on-off, pcb about 2 seconds cycle?
Del has a good point:
>>If it is the pcb the burner will die before APS clicks off.<<

 

[Soggy_weetabix]

another potterton boiler with inherrent M/D's

Is that why any emergency boiler breakdown service company excludes potterton?

My boy seems to make better stuff out of blu tack and cardboad.

David

 

[corgiman]

which ones soggy?