I have recently changed the 3 way valve and drained the system. I now have a problem in that hot water is getting to the inlet pipes at the radiators but the rads are not heating up. It seems that the water is not flowing back to the boiler. I've tried bleeding and shutting down all radiators expect for one. So all the usual air lock problems have I think being covered. Any advice would be appreciated.
No Heating
- Thread starter surfrider
- Start date
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Did you latch the 3 port valve in the mid position when you re-filled the system. In the relaxed position the HW port is open and the CH port is closed, so you could have a air lock if the valve was not latched.
Yes, I had in the mid position. The valve seems to working fine with water going to the cylinder and heating feed as required. However the return pipe from the heating circuit is cold. For some reason the water is not circulating. The pump and boiler are working fine.
So it's a blockage of some description. 'air' or 'something solid'.
Still think you have to consider a possible air lock.
Pump may be working but did you also bleed pump.
A working pump is going to find it difficult to move a pocket of air, cause the air will compress, and bleeding radiators does not rid air from pipe work.
You could try increasing pump speed.
Any other bleed points.
See the FAQs for methods to remove air locks using hose pipe and mains pressure.
On one occasion I removed a radiator which had just been fitted, so I could open the valves on the flow and return side to get rid of a air lock.
Still think you have to consider a possible air lock.
Pump may be working but did you also bleed pump.
A working pump is going to find it difficult to move a pocket of air, cause the air will compress, and bleeding radiators does not rid air from pipe work.
You could try increasing pump speed.
Any other bleed points.
See the FAQs for methods to remove air locks using hose pipe and mains pressure.
On one occasion I removed a radiator which had just been fitted, so I could open the valves on the flow and return side to get rid of a air lock.
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I've looked at the pump which is located in the boiler and can't see a way of bleeding it. But it does appear to be working ok. The pipework upstairs is hot to the radiators but is still not circulating through them. I have three loops upstairs coming off 28mm pipework from the boiler. The return pipework is cold. Could this be an air lock in the return 28mm to the boiler stopping all circulation and if so can you offer any advice on how to remove it ?
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