DIY Doctor

air lock after installing a new radiator

Postby uk_ducati » Fri Feb 11, 2011 8:20 pm

I installed a new radiator for a customer just before christmas and since then i have had a lot of trouble with the system. The system is a gravity fed system with a greenstar boiler.
The problem is that the living room radiator (which is on the end of the run) keeps getting an air lock in it and stopping it from working. the usual thing that happens is the heating will fire in the morning and 99% of the time all radiators will heat up. Then it will go off. In the afternoon the heating will come on again and this is when the prob will start. all of the rads will heat up apart from the living room rad. To get it going again all you have to do is turn the trv to off on the new rad for a few seconds, there will be a bit of gurgling from the living room rad and then it will work. At this point you can turn the trv back on on the new rad and all is well again. Just to mention that if the new rad is left off the system works fine. this has been going on since the new year and i do not know what to try next. the new rad was teed off just before the feed to the living room rad.
Could it be the pump is now not powerfull enough to run the system with the new rad on it and any air that is in the system blocks that rad as the pump was just on the limit before the new rad was put in.
the pump is a british gas multihead g model and is about 2 years old. I was thinking of putting a grundfoss 15-60 in to see if that works. The system is nice and clean aswell so there are no blockages.

any advice would be much appreciated as i have run out of ideas.

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Simply Build It

Postby stoneyboy » Mon Feb 14, 2011 10:36 pm

Balance out the system using the lockshields on the radiators.
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Postby uk_ducati » Wed Feb 23, 2011 7:15 pm

Yep. Tried that.

It will work for a few days then that rad will stop working. The only way to get it going is to turn off some of the rads with the trvs and there will be a gurgling noise from problem rad and all will be fine again

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