I have an open system with header tank. Had problem in that upstairs rads worked continuously but downstairs were cold.
I have replaced the pump, but had to drain down the whole system first to do it.
I refilled the system, bled the rads. I then turned the heating back on at the controller and increased the thermostat.
The pump started no problem. I turned down the thermostat to stop the pump. I then bled any air out of the pump (large screw head in middle of pump).
Started again and left running, but pump sounds noisier that I thought it would.
My problem is that the heating doesn’t work!
I have used a hose to jet water via the 22mm outlet at the bottom of the header tank to move any air locks but still nothing.
The only time I can get any heat (or the boiler to fire) is if I have the pump running as normal and connect a hose to the drain outlet on the downstairs rad I used to drain the system. I figured it may push the air out having both ends open. (I also did it to make room in the header tank to allow me to use the hose to jet water in as mentioned earlier)
Hope this made sense??? Totally at a loss as to what to try next. Got to be an air lock but how the bleep do I get rid of it?
Thanks in advance
p.s. I am not a plumber but can usually do most plumbing jobs if its explained in plain basic idiot guide English (don’t tend to know the technical names for bits, tools or techniques)