Anyone know how to drain a sealed central heating system ?

Sanjøy · Post by **Sanjøy** » Tue Mar 27, 2007 11:55 pm

Down in London this weekend working on the flat and belive it has "black sludge" issues. Been reasing http://www.diynot.com/forums/viewtopic.php?t=11325 but looking for more first hand advice as not Roy Keane on the quoted 3-4 days @ £85 per hour.

Cheers

SP

haggis catcher · Post by **haggis catcher** » Wed Mar 28, 2007 6:58 am

Wee Robbie could also help

thinfourth · Post by **thinfourth** » Wed Mar 28, 2007 8:11 am

£85 a fecking hour

Lawrence you need another apprentice

gorrie · Post by **gorrie** » Wed Mar 28, 2007 9:27 am

I've only drained a standard open system (with header tank) when doing a chemical/flush treatment which is easy enough.

My brother did my system in my old cottage which was a combi boiler... and ended up with air in the system. Boiler kept blowing itself out.

Think there was a pressure valve next to the combi from memory that we managed to get the air out through in the end.

MacK · Post by **MacK** » Wed Mar 28, 2007 9:59 am

I've 'tinkered' with different types of heating systems, but others on here are more qualified to comment.

But, what I think you are wanting to do is flush the system, to get rid of the "black sludge" issues. As described on that web site, drain from the lowest part of the system, or you may need to drain each radiator individually, with a drain open (and hosed or with a bucket underneath

) turn on the quick fill loop, and this will bring new clean water into the syste, and flush out the crap. I would advise doing this at several radiators, so you are not flushing the sludge all around the system, maybe starting on the nearest radiator to the boiler...

You can also get chemicals for cleaning/flushing that can be added. You will also need to add an inhibitor. Screwfix, or B&Q should stock them.