replacing 3 port valve

[sam1670]

hi all, i'm replacing the 3 port valve this week and was just wondering for a couple of pointers. i take it, its just a case of draining to central heating side at the lowest radiator, but tying the hot water ball cock supply off. or would i need to drain hot water side as well.
after replacing the 3 port valve do i need to bleed system or just run the system up.
any help would be appreciated

 

[Boilerman2]

Yuo need to tie up the ball valve in the SMALL F&E Cistern NOT on the big CWDS tank, afterwards don't forget to add Inhibitor and yes you will need to bleed the system start at the lower rads and finish upstairs,

from your questions - are you sure you have the skills needed - getting DIY put right after the disaster is usually more expensive than getting a heating engineer in to do it in the first place!

 

[sam1670]

i've done most things on my house so far and been all good. what it is, is i need to swop the valve round becasue it was fitted the wrong way around when we moved in. 2 weeks of messing around to discover this!!!!! is an inhibator the flush through stuff? anyway thankyou for your pointers

 

[nickso]

Bung it. Draining down is a waste of time.

 

[sam1670]

bung it? im not sure what you mean could you please explain, i might be sounding like a ****, but im a mechanic but not clued up as yet with plumbing speak. cheers

 

[45yearsagasman]

Bunging a system consists of creating a vacuum in the pipework by closing off the cold feed from the small tank and fitting a stop to the open vent pipe on the same tank.
Draining a small amount of system water creates a vac and you can then change components.
When work is complete restore the cold feed first and then remove the open vent stopper.
Doing it this way for the first time focusses the mind!!!
You also don't lose any inhibitor as when you drain down.