Central Heating Pump

[Andy Hall]

I don't know - can't get the staff these days :-)

[John]

In article , John writes

No progress yet (although a careful look at the pipework shows that the pump can be isolated by closing four valves (two on each side - there are two boilers with their own isolating valves and two rings with their valves).

Anyway, the home boiler has come out in sympathy! It is an old Potterton

80 and the fan starts but it fails to try and ignite. I have cleaned the fan and blown through the tubes to the air pressure switch but after a period of intermittent firing it is now sulking big time!

Is it possible for the fan to get slower (i.e. not create sufficient draft) so that the APS will not detect sufficient change of pressure? Is it more likely the APS has finally given up the ghost?

Ho hum shiver!

[Ed Sirett]

Yes the bearings can get sticky and slow the fan down. You can check the APS by blowing _very_ gently into the correct tube.

[John Stumbles]

If the fan's running at all it's propably OK. It the pressure switch isn't clicking over check the plastic tubes: they can split.

[John]

Just to make it more confusing, it has stopped sulking and is working again - that is partly what makes me think it is the fan running slow.

[<me9]

Does the fan spin freely? if not clean and lube the bearings. That is the usual cause of slow running fans.

[Ed Sirett]

That is also a _lot_ easier to say than to do. Most of the bearings are very inaccessible within the fan unit, and any lube that can be got in tends not to work for very long.

>

[John]

I will take the fan out at the weekend and have a good look - when I gave it a brief check there did appear to be some lubricant around one of the bearings and attendant fluff.

Fingers crossed it seems to be running OK at the moment - I half wondered whether the direction of the wind (across the outlet) could cause pressure/flow fluctuations.