I have to replace a 3 port valve on my Honeywell Y plan heating
system. I cannot find where the drain cock is on the system and I need
to drain the system down below the valve. I have made up a fitting
with a drain cock that I intend to fit onto a radiator valve and drain
the system from this point. The faulty valve is jammed in the mid
position and the faulty pipework is 8mm fed from a manifold. Can
anyone anticipate any problems? Thanks.