Getting my heating started again?!

[AndrewHD]

Hi everyone! hope you can help me - i just drained down my heating system, installed two new radiators and re-filled and bled my system... sadly it's not getting hot!

I've bled the radiators and all of them are full now. when i turn the heating on, the pump (Grundfos UPS 15-60) makes more noise than it used to do and doesn't seem to pump the water round much.
THe pipes around the pump get hot, and the boiler seems to produce some hot water, but it looks like it gets stuck there...

I've bled the pump, using the screw on the side and released a bit of air from the thumb valve near the pump...

Is there anywhere else I should check, or anything else I should do, as it seems there's an air lock in the system that I can't budge.

Any advice is appreciated.
Andrew

 

[JohnD]

have you got a feed and expansion tank in the loft? How deep is the water? How deep is the mud?

When you bleed the highest radiators in the house, does water squirt out forcefully?

Is the pump hotter than the pipes connected to it?

 

[AndrewHD]

SOLVED:

Took the drain screw out of the pump for, maybe. 45 minutes with it pumping on medium... occasional spurting of bubbles interspersed with about 5 litres of water occasionally drained from an old cat litter tray... now the radiators are all hot and lovely.

Thanks all

 

[dilalio]

After a drain down it’s almost always air... or sludge dropped down through the system during the drain.