Potterton Profile 100e Boiler problem

[nickcat65]

Hi,
Have problem with the above I think. Boiler will run on HW only no prob.
When put on CH only or HW+CH runs for about 20 mins and then stops, pilot stays lit, pump keeps running, room stat still calling boiler fan still running. Just main flame not on.
If you turn everything off and leave for a while then start up again it runs up fully again but then does the same.
Recently had a radiator moved so system drained but have bled everything.

Any ideas please.

 

[Puddle]

Your clue here is the pilot light being alight,this is a electronic boiler and does not have a permanant pilot light therefore if alight ,the boiler has tryed to start and not sensed the pilot light to activate main burner or the boiler has gone off and pilot light has stayed on,then tryed to restart,sensed pilot still on and cut out
As the ignition lighting the pilot we may asssume electrode lead not faulty
,fault intermitant so earthing and dc detection probably ok therefore would look at faulty gas valve with main burner or pilot coils/jumpers faulty
If pilot side faulty you would have to turn gas off/taking pilot out to re-start
If you are not doing this you could possible get away with just replacing slonoid coil for main burner on the gas valve,well a gas safe engineer could

 

[nickcat65]

Thanks for reply. Excuse me if am being thick but why would boiler flame go off if not up to room temp and why does it not seem to happen with just HW selected.

Thanks in advance.

 

[wolvesgasman]

Have you recently replaced the wax divertor?

 

[nickcat65]

Sorry whats a wax divertor ?

 

[Puddle]

The boiler may go off many times before the air room temperature is reached,the boiler heats the water in the boiler then may close down until hot water circulated,then restarts,keeps doing so until room thermostat or programmer turns it off

It probably is happening on hot water but you notice more on heating side


wax divertor ??,this is a potteton profile not puma

 

[wolvesgasman]

This model I believe uses a wax capsule which expands when hot to open heating circuit - it needs replacing every now and then - you will need to buy the complete unit to make it easier but not too arduous a task anyway!