Potterton Puma 80e Pump problem?

[Sandytoe]

My combi boiler works perfectly, but whenever the central heating is switched on the pump is constantly whirring, even when the thermostat kicks in and the heating flame goes out.

I recently had to get the control board replaced as part of it burnt out, after fitting a new one the system worked perfectly - until there was a leak from one of the pipes upstairs which caused a drop in pressure - but that has also been fixed and the pressure is fine now.

Any ideas why the pump is doing this - it started a week ago?

 

[boxster]

sounds like you didnt vent the pump, the pump may have air in it. failing that turn the pump speed down..

 

[Sandytoe]

Aaah - how do you vent the pump or turn the speed down.

 

[boxster]

right can you see the pump inside the boiler. look at the front of it, you will see a metal circle with a screwdriver slot. turn it untill water comes.. on the side the pump may be set for marking ||| turn it to || or even |

if you need more detailed advise let me know and i will give it in detail..

 

[Sandytoe]

Thanks for the tips Boxter - I'll give it a go tonight and let you know how it goes

 

[Sandytoe]

Boxter, the pump doesn't seem to have a metal disc with a screwdriver slot, it has a bolt in the middle, with a message about unscrewing the central knob if the pump locks. Is that what I'm meant to loosen?
Also i couldn't see round the side to check the |, || or ||| marking - shall i take the right hand side panel off?

Cheers,

Nic

 

[breezer]

that looks similar to my potty boiler, you see that black knob on the pump, undo that (the potty pump is smaller than you "average " c/h pump and has that black knob instead of big brass screw)

 

[boxster]

oh that model:

yer as breezer says turn the black thing, untill water comes. good picture its helpful!

 

[ChrisR]

I wouldn't be happy to turn thr pump down - the speed is needed for HW heat transfer.

The pump carries on for some time after the flames have gone out to stop the boiler overheating - pump overrun . A couple of minutes I think. On older boilers there was a separate stat for that - not sure how this one works buy it could be that mechanism faulty.

 

[Sandytoe]

I turned the black knob but no water came out. I unscrewed it all the way until it was just turning the spindle of the pump. I don't think you can vent the pump through that...

Any other ideas?

 

[Sandytoe]

Hello out there ....

Have any of you got any further ideas?

Thanks v much

 

[ChrisR]

That's all the vetnting a Puma pump needs. Turn the tyhermostat down so the heating goes off. The pump should run on for a couple of mintes or so. Does it never go off? If not it does sound like the pcb., though I'd check the CH thermistor first. You need an Ohm meter. Values are in the manual.