good installers fit a drain tap on where ever pipes drop downwards to aid draining, turn off the incoming water to the boiler, look under the boiler for a drain tap (this will drain all upstairs only if the boiler is downstairs) attach a hose pipe,fasten on with a jubilee clip, drain water straight outside after a minute go and release the bleed screws on the upstairs rads to aid drainage. find your other drop drainage points in the house and repeat the above till water ceases.
modify your pipe work close all drain taps and bleed valves slowly refill system testing for leaks where pipework has been modified if o k continue to fill via the filler loop pipe
wirecutterman, December 2009
