by htg engineer »
Mon Nov 05, 2007 7:20 pm
With the hot water being gravity fed, it's not like a fully pumped system and the heating should work with the pump fitted both ways. But it is best to be pumping away from the boiler (the way yours is fitted) Turn off the downstairs radiators and see if the upstairs heat up it just sounds like an airlock.
Try turning the pump speed up to III.
If no luck, you could try turning the pump round and see if it will push any air out of the system. But put the pump back pumping away from the boiler when finished.