Heating and Hot Water, banging noises/gurgling - pls help!

[Cat-Kicker]

OK, so info is:
Boiler - Potterton 15HE Promax
Vented system (open tank in loft, immersion in airing cup)
Tank in loft is full of water.
I have bled all radiators (no air present).
I have bled all drain valves (some air present).

The problem:
When the system comes on (either C/H and/or H/W), we get some gurgling noises as the boiler starts to heat up, then some banging noises from the pipes, then the boiler cuts-out out and tries again a few minutes later. I presume this is a safety cut-out caused by over heating or low pressure? All rads except one are cold - the hot one is probably nearest the boiler. Thats it really - help please
So far I have:
Listened to the pump - it does not seem to be working - could this cause the whole problem with both the C/H AND H/W?

Does the one pump drive both the central heating and hot water in a vented system?

Background - I did move a radiator a couple of weeks ago but hardly lost any water and system has been fine for the last 2 weeks.

Cheers for any help!.........
Gary

 

[seco services]

sounds like the pump is jammed or knackered.
remove the centre screw on the pump and place a screwdriver in the hole see if it turns freely maybe just stuck.

yes it will operate both hw/heating and if not circulating water boiler will cause banging and overheat stat will shut it down

 

[Agile]

The boiler does not have an integral pump so you can safely play with it.

That sounds like a typical case of the pump not turning.

Check both pump valves are open and then see the FAQ on this site for testing the rotor to see if its free to turn.

Its probably seixed up but will mosy likely to be retrievable.

Tony

 

[Cat-Kicker]

Thankyou very much indeed both.
Did as you suggested and the pump was stiff to turn. It lossened up a bit and I got i turning more easily. Then tried the system and all working ok - pump came on. I'm guessing the pump should just spin freely though on a bearing, so looks like it will need replacing.

Cheers again.
Gary

 

[Cat-Kicker]

Thankyou very much indeed both.
Did as you suggested and the pump was stiff to turn. It lossened up a bit and I got i turning more easily. Then tried the system and all working ok - pump came on. I'm guessing the pump should just spin freely though on a bearing, so looks like it will need replacing.

Cheers again.
Gary

 

[seco services]

check that the f/e tank in loft is feeding the system. as this is why the pump may of seized in the first place being dry.

 

[Agile]

check that the f/e tank in loft is feeding the system. as this is why the pump may of seized in the first place being dry.

Or even seixed !!!