No Radiators on

[alfier]

I've just drained the system and changed the 4073 diverter. After refilling I have hot water and all the pipes to the 4073 are very hot and both lights on the controller light ok, however the radiators aren't warming up and the boiler only switched on for about 5mins.
I think the return pipe (I may be wrong) to the boiler is stone cold. I drained the system from a downstairs radiator. Could the boiler an old 80N have an air lock? If so how do I remove it?

 

[seco services]

try turning the hw off so all the flow gos to the rads.

 

[crockett]

How about manually holding the valve open to shift the suspected airlock? Remembering. of course, to close the valve after.

 

[alfier]

Thank you holding it in manual cured it. Simple when you know How!