Hi,

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.

Is there some valve inside boiler somewhere? Boiler is about 8 years
old now and some rads even older although replacing room by room when
decorating. Unsure if anything has been added to system before but
it's been drained and refilled quite a bit recently so thought I'd
better add something.

Any tips greatly appreciated.