Performa 28 Central Heating Problem

[Michael01474]

Hi all, our Performa 28 has been showing the Pump/Low pressure warning recently. I can get it to reset if it's been off for a while.

The pressure looks fine and I've checked the pump which appears to be working. The hot water is fine. Assuming it's been reset it will happily turn on as per the timer and run until the timer tells it to go off. After a short while it will then show the Pump/Pressure fault by flashing the 60 degree led and then needs to be left before I can reset it.

I noticed this morning that the pin on the pump proving switch seems to stay in the up position after the pump has stopped (or it just drops back very slowly). The diverter valve was new in June of this year. If, once the boiler has stopped, I push it back down gently it won't error and the boiler will restart quite happily.

Does anyone have any ideas?

Thanks

Michael

 

[MeldrewsMate]

Yes.
You are right to suspect the pump proving switch.
You will need to isolate and drain the boiler, remove the 1 screw holding the microswitch in place, then remove the 4 screws holding the diaphragm assembly. A dumpy screwdriver is best for this, as there's not much room.
Disassemble and clean the actuating shaft so that it runs cleanly up and down its guide. You may only need a fingernail for this, or a blunt screwdriver if the deposits are stubborn.
Lubricate your shaft (ooh, err!) only with a silicone based grease - WD40 and mineral oils/greases will rot the seal.
Reassemble in the reverse order, as Mr Haynes used to glibly say.

 

[Michael01474]

Thanks for the reply. Tried to put a bit of silicone grease on the pin whilst it was up tonight which seemed to help a little. It would only need to drop a tiny amount more to "un-activate". I'll take it apart properly tomorrow if I get back from work in time.

Thanks again.