So does this sound like a balancing problem?
No balancing is about flow this sounds like air getting in. Which is about pressure issues or corrosion. With inhibitor it must be pressure issues.
When the system is fully cold does the pressure drop sharply? That would indicate too much air in the expansion vessel. When you try to bleed it is the system warm at all or do you bleed it stone cold?
What's happening in those 20 seconds if the bleed valve is open and no water or air is coming out?When I bleed it no air comes out and after about 20 secs hot water finally starts coming out
What's happening in those 20 seconds if the bleed valve is open and no water or air is coming out?
Does the radiator stay *hot* after you've bled some water through it, or does it slowly cool down again?
Sounds like one side of the rad is heating from convection, and bleeding it just lets some more hot water through.
Are you absolutely sure that both valves are open, and that water is circulating through the rad *after* you've let some water out?
Does the return valve get warm at all?
Turn other rads off, one at a time and leave for 10/20mins before turning off another one. See if this encourages flow through the vertical
yes. This does help the vertical
Then just balance the system properly.
Close all rads except vertical rad and then crack open lockshields on other rads until they get hot... Some will only need an 8th of a turn open.
If the vertical rad goes cold again after this, then you need to start looking at pump head and other issues... Piping perhaps.
But try accurate balancing first.
thanks will do. Should both valves be fully open on the vertical?
The vertical distance between the ground floor and loft is irrelevant; a pump's "head" is just a way of measuring the pressure the pump produces.Whats the pumps head rating in the boiler. It might not be powerful enough to from ground floor to loft.
Yes.
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