Central Heating - a...
 

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[Closed] Central Heating - a quick question

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Over the summer I drained down my central heating system and replaced the Heating side actuator valve. Quick test and its back working OK, apart from one radiator in the downstairs bathroom.

I presume this is an airlock somewhere in the system but I've bled all the rads and they are all full, although the heating has only had a half hour run to test the system. Once the heating has run for a few hours, will this airlock migrate to a radiator to be bled out or do I need to do something else to get heat to the one remaining cold radiator?

Thanks


 
Posted : 09/09/2021 9:31 am
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Caveat - IANAP/HE
I think if you turn the TRVs off at every radiator except the cold one on that down loop it'll force the pump to push the water to the cold radiator, which should shift any airlock and enable you to bleed the air from that cold one. It should then start to heat up. You'll then need to crack open the TRVs on the others gradually and balance the system so that they get enough water to heat up but not so much as to starve the furthest one, otherwise it'll remain cold.
I think that's how it works.


 
Posted : 09/09/2021 9:36 am
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Run heating, turn off every other radiator, top down, this will push the air lock out, then turn all back on. Run for a while then re-bleed the rads.


 
Posted : 09/09/2021 9:45 am
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Nice, thank you


 
Posted : 09/09/2021 10:34 am
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I presume this is an airlock somewhere in the system but I’ve bled all the rads and they are all full, although the heating has only had a half hour run to test the system. Once the heating has run for a few hours, will this airlock migrate to a radiator to be bled out or do I need to do something else to get heat to the one remaining cold radiator?

We have that, whenever I drain the system it can take an age to force air out of all the pipes, I just switch the boiler off and stick the pump on full power and leave it for an hour and it eventually clears it all. I can hear the pipes gurgling as the air finally escapes....

Our normally clears via the header tank but I normally rebleed all the radiators afterwards as there's often a bit of air in there.


 
Posted : 09/09/2021 11:08 am
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Creakingdoor pretty much has it as far as initial work to fix it is concerned, however I do have to ask why you're draining down your system unless you've done it to fix a problem or add a radiator?

Regular draining down of central heating and replacing with fresh water causes a lot of unnecessarily corrosion and should be avoided as much as possible.


 
Posted : 09/09/2021 11:50 am

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