Boiler not firing after water drain

[dmw571]

Hello All,

I've got a Potterton Prima F40 boiler and all was working well. About two months ago I took the system off line, turning off the timer/boiler, setting the thermostat really low and draining the water out of my system.

The heating system is a simple setup (not combi etc) and I have a large water tank in the loft and a smaller one which feeds the heating system.

I've fitted a new radiator in the kitchen and was well until it came time to turn the system on. I've refilled the system, bled every radiator and also the vent by the water pump/three way valve switch, the system appears to be all water (no air venting anywhere).

I can switch the boiler on and it fire up for around 5 mins. Then it switches off and there a loud gurgling sound coming from it, sounding as if air is escaping up through the pipe!

Am I missing something here? I've let the system cool down and treid again resetting the boler using the little switch underneath. The same happens.

Any clues or ideas? How can I ensure there's no air in the system other than opening and bleeding the radiators?

Thanks,
Darren

 

[breezer]

does the tank in the loft have any water in it?

 

[dmw571]

Hi,
Wow that was a quick update. Yep the smaller tank is full (the larger tank feed the hotwater system I believe - baths etc). I've also noticed that the pump in the airing cupboard gets hot after the boiler has stopped firing up. So I assume the pump is working, but it just can't pump the water anywhere! Is there a specific place I can look/check for blockages.

Should I be running through some sort of blockage removing liquid or primer before trying to start the system?

Darren

 

[dmw571]

FYI:
The pump had stuck and the impeller needed releasing - called a plumber in and after removing the central screw (big) he used a small screwdriver to flick a small screw within the pump mounting which released the pump.
So we have nice warm water and a warm house again: