I have a pump fed central heating system, I have recently de-gunked the system and replaced the pump due to the radiators not heating up properly. I have a manifold type system where all the rads are fed from a central point, non of my rads are getting warm now, but if I remove a rad and open a valve hot water comes out at a decent pressure. I believe that they are all airlocked, how do I remove the air?
Cold Rads
- Thread starter airlock
- Start date
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If every single one of your rads is airlocked, it is a poorly fitted system.
Have you made sure the pump is primed, as if its in a position where water will not automatically flow down into it (ie. at a high point in the system), it will not pump as centrifugal pumps cannot pump air.
Also, if none of your radiators are warm, how did hot water come out of the valve.
Have you made sure the pump is primed, as if its in a position where water will not automatically flow down into it (ie. at a high point in the system), it will not pump as centrifugal pumps cannot pump air.
Also, if none of your radiators are warm, how did hot water come out of the valve.
In fact, forget my last post - I need more info about your system.
Ie. is it a sealed system or is it gravity system.
Where is the pump located, and can you hear it working.
Does the boiler cycle on and off, or does it stay on like it should normally.
And it actually probably isnt a problem with the pump if the rads were cold before you replaced it.
It may in fact be some sort of blockage in the pipework.
Ie. is it a sealed system or is it gravity system.
Where is the pump located, and can you hear it working.
Does the boiler cycle on and off, or does it stay on like it should normally.
And it actually probably isnt a problem with the pump if the rads were cold before you replaced it.
It may in fact be some sort of blockage in the pipework.
I'm not sure how you prime the pump but it is pumping water as water comes out when you bleed it. The pipe from the pump to the radiator manifold gets hot but the pipes feeding into the rads do not. If you remove a rad and undo the valve this allows the water to flow and it starts to come out hot. If you put the rad back on it will heat up but will soon go cold again. Its as if there is air in the return path that isn't allowing the water to flow around the system.
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The system is gravity fed.
The pump is located at the bottom of the h/w tank on the landing.
The pump works fine as its new, the boiler cycles on and off but I guess this is because the heat isn't getting dispersed.
A blockage is possible, if I undo a valve on the return side should I get a continious flow of water?
The pump is located at the bottom of the h/w tank on the landing.
The pump works fine as its new, the boiler cycles on and off but I guess this is because the heat isn't getting dispersed.
A blockage is possible, if I undo a valve on the return side should I get a continious flow of water?
Priming the pump means basically putting water into it and ensuring a constant feed of it. As the pump cant pump air, it just spins and does not pump any water.
But that is probably not the problem anyway - it was just a thought.
As you can narrow the problem down to the return side of the system.
Just ensure any valves/stopcocks are open (valves that are on the pipework, not the rads)
Unfortunately, you are probably best letting one of the other pro plumbers answer your question - as I find it difficult to diagnose without looking at it.
There are simply too many variables.
But that is probably not the problem anyway - it was just a thought.
As you can narrow the problem down to the return side of the system.
Just ensure any valves/stopcocks are open (valves that are on the pipework, not the rads)
Unfortunately, you are probably best letting one of the other pro plumbers answer your question - as I find it difficult to diagnose without looking at it.
There are simply too many variables.
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