Boiler not staying on

[adamt]

Hi, I have just drained my central heating system in order to remove a radiator for decorating. Replaced the radiator and bled the system and all seemed well......until I tried to put the hot water on. The boiler fires for a few moments then switches off. Same happens when I switch on the central heating. Can anyone advise on what the problem may be?
Also noticed that the pump still circulating quite some time after the heating has been switched off. (not sure if it always does that)
I have a Potterton gas fired boiler.

cheers,

Adam

 

[stoker122]

Did you shut the power off when you drained down? If not
Pump could have been running dry.
Or could be you still have air in the system stopping circulation.

 

[Kyle87]

Still air in the system maybe and boiler overheating that's why it's cutting out.

 

[adamt]

Thanks for quick response - I thought it might be air lock.

How do I clear an air lock????!!!!

 

[stoker122]

Have you vented the pump via the removable plug in the front?

 

[heliotrope]

Not usually necessary to drain down to remove a rad, but anyway...........

If yours is an open vented system with a cylinder then check for an air vent somewhere near
the cylinder.

Have a rag or cup ready and open up the large slotted screw on the pump and keep it open until
air stops coming out. (do this with the pump running).

 

[adamt]

it is a towel radiator, so had to emty it before removal.
yes it is a normail open system. wasn't sure if I should open the screw on the pump with it running or not. Will give it a go.

thanks.

Not usually necessary to drain down to remove a rad, but anyway...........

If yours is an open vented system with a cylinder then check for an air vent somewhere near
the cylinder.

Have a rag or cup ready and open up the large slotted screw on the pump and keep it open until
air stops coming out. (do this with the pump running).

 

[AWheating]

probably an air vent in the cylinder cupboard needs vented or one somewhere else of the system.

 

[SimonG]

it is a towel radiator, so had to emty it before removal.
yes it is a normail open system. wasn't sure if I should open the screw on the pump with it running or not. Will give it a go.

thanks.

Doesn't matter still shouldn't have had to drain the system. It'll be an airlock but hope you splashed some inhibitor back into the system when you were filling up.

 

[jam1979]

u was lucky its filled back up usually that's when u come across a blocked cold feed