Potterton Prima 60F Boiler problem

[williamft]

Can anyone help!

Potterton Prima 60F. Balanced flue boiler.
Starts up ok, fan running, electrode sparks ok, pilot lights and main burner fires up.
Then after about 60 seconds of running, boiler cuts out and won't re-start for a couple of hours.
The overheat thermostat does not trip.

Noticed over the past few months that the boiler has been overheating and overheat thermostat tripping, so I turned the control thermostat down to 2 and boiler didn't overheat.

The pump has been sounding noisey, but is running.
Could the pump be causing this problem?

Any ideas!!

REGARDS
BILL.

 

[Gasman28]

Check to see if the system has water in it - normally in the small F & E tank in the loft. Pump could be faulty as you said.
Overheating is normally due to a lack of water.

 

[twgas]

Try giving the highest rad a good bleed, if it stops after a little while (either air or water) the cold feed may be blocked and having water in the f&e tank does not mean there is water in the system, although if its empty ignore my tip and fill it up.

 

[williamft]

Hi,
Thanks for replys, checked radiators and bled ok plenty of water came out, no air came out.
Feed/expansion tank full of water.
Any more ideas?

regards,
Bill

 

[gas4you]

Pump needs looking at, especially if it is noisey.

They can sound/appear to be spinning but not actually circulating

 

[williamft]

Thanks.
I have a new pump ready to fit, but it's a big job due to constricted area and pipes in the way etc. so will wait till summer now.
I have an immersion heater as backup for hot water, the wife will just have to wear a cardigan for now!

 

[Agile]

That does not make sense!

If you cannot use the boiler now then you might as well fit the new pump now without waiting until the summer.

If you replace with the same model you can usually just replace the pump head after undoing the hex socket screws.

By the way yours is a fanned flue and not a balanced flue.

Tony

 

[williamft]

Thanks,

Will try your suggestion, does the pump head come apart easily or will I need a puller of some sort.

Bill

 

[Agile]

Usually they come off easily but Grunfos can be a bit sticky and need hitting with a mallet not too hard.

Tony