Drain Valve not opening up ...

[namsag]

remember the mrs saying are you not draining the system to fit that valve,
Watch an learn woman watch and learn.
Old valve out trv on and it was the wrong fekin thread water spraying everywhere .
So do you want the hose in then she says.

Not as bad as the mate taking out the 3/4 inch safety valve throwing over his shoulder only to find 1/2 inch doesnt fit

 

[steved101]

the system I have is open vented ... does this make a difference?

MT washers? what are these... do normal stores like wickes sell these or a plumbing shop??

 

[kevindgas]

open vent is exactly that OPEN in the loft is a small tank with 2 pipes 1 in the bottom (the cold feed) and 1 over the top (the open expansion vent) if you are not draining down then these need securely blocking for the duration of your valve change so as to suspend the water in the system
i always turn off the other rad valve as well so only 1 pipe from system + contents of rad to contend with.
when rad valve is detached from rad I get about a bucket of water before it stops running usually

if you are draining down then go to a good plumbers merchant they know what a MT washer is