i am attempting to replace my basic rad valves with thermostatic ones, do i need to drain the system and if so how do i do that.

mike, October 2009

there should be a drain valve on the rad furthest away from the boiler or just on the ground floor, have all your rad valves open on the other rads, connect a hose to the drain valve & open & just let the water run away until it stops, there should be a pressure relief valve on the boiler which you can turn until you hear water running away & see the pressure gauge drop, this will drain the boiler very quickly, if no drain valve then you will have have to drain each rad in turn

bamba, October 2009

attatch a hose pipe to a drain point open the drain point allow water to flow out after a few mins open bleed valves on rads upstairs wait til water stops flowing then replace valves may have a little water in still catch with tray dnt worry it wont be under any pressure

x, October 2009

Just let the pressure disperse through the rad bleed valves, then you can get cracking with your valves. Each rad will still be full of water though so be prepared for that, and repressurise the system before you set it going again.

John, October 2009