Radiators not heating properly.

[stephan0032]

Our central heating system is very noisy, boiler is an old traditional type with water tank. We are constantly having to bleed our radiators and the upstairs radiators don't bleed properly, air stops hissing out and no water comes out but downstairs are fine. Have tried balancing the system recently. Only bottom third of radiators get hot.

Header tank is full and water seems to be able to flow into the system as far as I can tell. Have bled radiators with boiler on and off.

Any hints or tips would be appreciated.

 

[oilman]

......... air stops hissing out and no water comes out.......

Header tank is full and water seems to be able to flow into the system ........

You have a blockage somewhere. Shut off the water supply to the header tank, and drain some water from the system. The tank level should drop. I suspect it won't.