Noisy pump

[spoon]

Can anyone help?
I have drained the central heating system from the drain point on the lowest radiator. All the upstairs radiators drained fully, but the downstairs ones had residual water. I then refilled the system, bleeding the radiators one by one until they were full of water.
On restarting, the boiler initially fired up correctly, but then went back to the pilot. The pump is making a screeching sound and on bleeding the radiators, water runs freely from all of them. I think there is an airlock but don't know what to do.

 

[nickso]

use a screwdriver to open the screw on the front of the pump to try and let the air out.

if that doesnt work shut down everything bar one rad to try and force the airlock through it.

you may have to be quite patient

 

[spoon]

use a screwdriver to open the screw on the front of the pump to try and let the air out.

if that doesnt work shut down everything bar one rad to try and force the airlock through it.

you may have to be quite patient

Thanks for your help, I had to try one radiator at a time, but it worked !