Draining my CH system ?

[UnoHoncho]

My CH system appears to have a lot of black sludge in it and I want to flush it out.

I've found the two draining valves near a radiator by the front door - As far as I'm aware the next thing I should do is turn off the feed to the header tank and drain off from the draining valves via a hosepipe into a drain.

How do I proceed next ? Do I turn the flow to the header tank back on and bleed the radiators and then repeat the process again until the system is clean ?

Any advice would be great!

 

[AnonymousImport]

I did mine last weekend. I tied up the float in the feed tank, drained the system, then refilled it adding fernox to the tank. Then I ran the heating for a couple of hours, drained it and then flushed it till the water went clear - tons of crap came out. I then refilled the system with the fernox inhibitor stuff (can get both these at B&Q) and obviously bled the radiators when refilling the system.

 

[AnonymousImport]

If you're going to do that make sure yo get the correct sludge eating solutions. Some older systems will be attacked by this stuff and you'll wind up with a waterfall in every room (well maybe only 3 rooms). Good stuff but read the label or talk to the plumbers merchants.