The story so far. British Gas recommended I pay them an exhorbitant=20 amount to clean out (powerflush) the system. Discovered that the=20 chemicals used cost < =A340 and it's doable on your own albeit without the= =20 powerflush bit.
I drained the entire system twice which took a few hours and the water=20 went from blackish to clear then to brownish. Couldn't figure out why it=20 was coming out brown so checked the header tank in the loft. Disgusting.=20 Ended up in the loft with various buckets and sponges/cloths cleaning=20 out the header tank. 1 hour later flushing the system again - another=20 couple of hours. Went from brownish to clear after two flushes.=20 Excellent. Put the sludge removal compound in (this was 4pm) and=20 refilled the system. The radiators upstairs were incredibly hot - result=20
- but downstairs were incredibly cold - not so good - so turned off all=20 the upstairs radiators to force the pump to do downstairs. This still=20 didn't make them all work. I think what happens is the sludge removal=20 stuff is so good that it absorbs all the crap in the system and then the=20 pump has to pump it all round until you remove it a week later so=20 leading to some blockages (I'm making it up here so could be wildly=20 wrong). All the sludge had collected downstairs as I found out when I=20 bled a litre or two out of the radiators to get them going. This worked=20 but the water coming out was disgusting and previously had been clear.=20 This was about 6pm when it was finally all up and warming the house=20 again but the house had been open all day and no heat (or hot water)=20 available. Cold kids and wife :-(
Anyway next weekend I'm draining it again and then adding the inhibitor.
Couple of questions
I put the sludge removal stuff in the tank in the loft. Presumably=20 there'll be some left in the tank. Is it best to clean this out (again)=20 before putting the inhibitor in?
I'm going to put thermostatic valves on the upstairs radiators once the=20 system is empty. Firstly are there any recommended types? Secondly I'm=20 not sure on one of the radiators which pipe is the one where the on-off=20 bit goes as it didn't have any caps on when we moved in. Does it matter=20 which side the valve goes?
Thanks
--=20 John Kelly
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