Potterton Performa 24 random burner lighting? New Switch?

[kuffdam]

Hi all.

Total novice here but would appreciate any thoughts on a Potterton Performa 24.

The burner has just started to randomly ignite and start heating the rads regardless of the setting being on HW only. I have resorted to leaving it at the off setting until we require either HW or heating.

I have checked some other topics in this forum and see that my first point to check may be the microswitch.

I can see there are 2 sets of switches on the diverter valve, the one at the front facing me retracts fine so I assume that's the HW switch, the switch on the top therefore would be the heating switch right?

I've found these and just need to confirm which one to buy??

http://www.heatingsparescentre.co.uk/potterton-c19/performa-c2543/performa-24-c2774#t25

Luckily my neighbour is a gas-safe certified engineer who can do the fitting for me.

All thoughts appreciated.....

 

[Agile]

It is almost certainly the DHW demand switch which is faulty.

Thats the one at the front of the div valve.

Tony

 

[kuffdam]

Thanks Tony.

Got it, the DHW switch at the front of the div valve (Part 248207)

So are those 2 sets of switches running in series then?

It seems as if the DHW switch 'works' fine it's just the CH switch that is jammed open now (the burner is now igniting permanently as opposed to the random lighting seen initially) when in any mode apart from off.

 

[namsag]

edit .....

 

[gavinda]

It is almost certainly the DHW demand switch which is faulty.

Thats the one at the front of the div valve.

Tony

Unless its the pump proving switch which is what I seem to change when this occurs.

OP best to cut the power and have your gas safe eng test for continuity through BOTH switches as you can't really visually test this fault

 

[Agile]

The pump proving switch works equally in CH or DHW.

If it makes when the boiler is otherwise off then nothing will happen ( as far as I recall )

I have never needed to replace the pump proving switch. ( Yet ).

Are the pins moving as expected?

Tony

 

[gavinda]

not digging Tony but, pump proving switch fires the boiler , of this i am certain but the stuck dhw spindle will trigger the pump, firing the boiler also. It is unusual for a microswitch to stick, usually the pin sticks, leaving the microswitch 'made'.

the last 2 times i've been called out, this has been the case. this is why fault finding of this type should always be done with a fluke meter as well as good engineering knowledge.

also OP be aware thers a few different harnesses (harnii ) for this range of boiler, double check the right one gets ordered, I've been caught out with this before, twice on the same job .

 

[kuffdam]

Cheers chaps.

The DHW pin (at the front of the div valve) moves up & down as I would expect when called.

The CH pin (on top of the div valve) is in the up position permanently.

 

[Agile]

Right then thats the fault!

You may get away with cleaning the pin and greasing with silicone grease! But for most DIYers replacing the gland is the easy solution!

Thanks Gasvinder for saying the pump proving switch activated the burn sequence. I will recheck that when I next see one on wednesday and then save it in my memory! Thanks.

Tony

 

[gavinda]

That's exactly what my last one was like.

Not bad for a parts changer

 

[kuffdam]

Right then thats the fault!

You may get away with cleaning the pin and greasing with silicone grease! But for most DIYers replacing the gland is the easy solution!

Thanks Gasvinder for saying the pump proving switch activated the burn sequence. I will recheck that when I next see one on wednesday and then save it in my memory! Thanks.

Tony

Cheers again chaps.

So you're saying I just need to grease the pin on the CH switch and that might do it? Could you clarify what you mean by replacing the gland?