Clearing an airlock in central heating system

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I'm afraid I am a DIY novice and have committed a massive faux pas. I have an old central heating system and was bleeding the radiators this afternoon when the boiler unexpectedly fired up as I had changed the timings on the control unit over Christmas. I suspect there is an airlock as the heating is now not working at all.

I remember clearing an airlock in a previous house by turning off all the radiators and then bleeding them and the pump. I have now bled all the radiators but can't work out how to heat the pump. When I turned the boiler on, the pump gets hot, but I none of the pipes leading to or from the pump seem to heat up at all.

Any advice about how to get the system working again would be greatly appreciated.


Many thanks in advance.[/url]
 
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What makes you think it is an airlock? from your description it sounds like the pump may be stuck or goosed
 
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What makes you think it is an airlock? from your description it sounds like the pump may be stuck or goosed
 
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Looks like your pump is oriented in such a way that bleeding will be almost impossible. The photo is of the back of it - the bleed screw is on the other side, silver screw inside a black disc

Does sound like a goosed pump though (definitely a technical term NigeF) in which case you'll need a new pump and two new valves as the ones you have WILL leak if you try to turn them off.
 
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Could be a sealed system, is there a pressure vessel anywhere?
It's a red cylinder about the size of a small pedal bin.
 
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When you bleed the highest radiator in the house, does water squirt out forcefully?

No water comes out at all when I bleed the highest radiators. I don't think i have a sealed system. How do I go about topping up the system? Do I recall correctly that there may be a small cistern in the loft which should top up the system?
 
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Maybe the ball valve has jammed. The tank should refill it's self.
If the water level in the cistern is up near the overflow then your looking at a blocked cold feed pipe.
Not really a job for a DIY novice.
 
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Maybe the ball valve has jammed. The tank should refill it's self.
If the water level in the cistern is up near the overflow then your looking at a blocked cold feed pipe.
Not really a job for a DIY novice.

Thanks. The ball valve had jammed. I have unjammed it and the system has refilled. When I now bleed the highest radiator, it squirts out with some force. There is now hot water going through the pump, but still no warmth reaching the radiators. Any more tips greatly appreciated.
 
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Is the motorised valve to the right of the pump open? Can you turn the pump round to access the bleed screw like already been mentioned?
 
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I rebled the radiators and now have about two thirds of the radiators working. However, still no luck with the last 4 radiators
 
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Turn the radiators off that are working, and three of the four that are not. When thats hot open one of the other three and so on until the airlock clears. Then open them all back up.
 

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