3 port valve replacement drain advice

[Newplumb]

Hi folks, would appreciate tips.

Header tank in loft, 3 port valve at 60 cms high from floor, couple of radiators a bit higher. Drain point for radiators on ground floor. Isolating valves on pump never been touched in 25 years. I guess I need to tie up the ball valve in the header tank, or just turn off the cold supply to it and drain the system below the level of the valve, but how do I know how much to drain? Does it help by turning all the radiators off at the thermostats and the isolating valve? Should I use bungs and if so where do I

put them.

Thanks

 

[Simon F]

welcome along.
if you bung the fill and vent then you don't need to do anything with the float.
put some towels down, crack open the 3 port and swap it.
better still if you have a wet vac as well.
or isolate cold to f+e tank, drain the whole system which is likely filthy anyway,
swap valve, refill and add inhibitor.

 

[stevetheplumber]

you cant do a three way with bungs jubilee the hose onto the drainoff turn of or tie up supply to tank and keep the hose at the level you want to drain to hooked over the door works for first floor valves

 

[GasmanxxxR1]

Ive done 3 port valves with bungs. Its helps if the pump valves are in good nick and you can turn them off, perhaps balancing valve on cylinder too

 

[Ch4 plumbing]

Yeah I've done a 3 port with bungs, just got to be quick....snatch it over put a towel down and bobs your uncle...

 

[dave1]

I use bungs all the time for 3 ports. It saves having to fully drain I just use vax to catch what water comes out.

 

[Newplumb]

I use bungs all the time for 3 ports. It saves having to fully drain I just use vax to catch what water comes out.

Thanks to all you guys for the help.