Lobster wrote:

wrote:

Wondering if anyone could help with the above. I have a sealed central
heating system(as far as i know) with a combi 80 potterton boiler.

I want to drain system and clean with fernox then add inhibitor. I
know how to fill it back up i'm just unsure how to drain it. I've had
plumbers in before who have drained it in a matter of seconds.

There should be drain cocks at the lowest point(s) of the system
(something like this:
http://www.screwfix.com/app/sfd/cat/...3349&ts=21170). Connect
a hosepipe to the output and open the valve at the end. You'll need to
open the bleed valves on the radiators (starting with upstairs!) to
release the vacuum formed inside the system to allow the water to flow out.

Oh, and when you're refilling later, don't do what I did at the weekend.
Having drained down, I removed the threaded plug from the end of the
bathroom towel rail to pour in my inhibitor, and then replaced it,
taking care it was sealed nice and tight. Went back to the boiler and
refilled the system; 5 minutes later going round checking I found water
pouring down the wall below the bathroom. Although I'd replaced the
plug in the towel rail, I'd forgotten that the bleed valve built into
the plug was still open. Oops. And to add insult to injury, because
the towel rail control valve happened to be closed at the time, I had
effectively flushed out of the bleed valve the contents of the towel
rail - ie, the entire dose of inhibitor! :-(

David

David,

Thanks for reply.

I'll go and have a look for the valve. Would it actually be inside the
boiler?
As I've said plumbers have drained system before and they seem to have
front cover off at the time and do not connect any hose etc. Unless I
have a hose on there already.