Replacing leaky isolation valve below boiler.

hdarren

The isolation valve that leads to the boiler from the filling loop has developed a leak through the screw. The water stopped coming through the screw once the boiler pressure reached 0, so I was thinking it would be easy to just replace the isolation valve since the valve from the water supply works fine. However, once I unscrewed the cap on the faulty isolation valve water started pouring which I didn't expect (luckily I had a bucket there). It filled the bucket half-way before I decided to put the cap back on.

Is the water coming from just the boiler? In which case to replace the isolation valve is it just a case of letting the water out until the boiler is empty? If so is there much water in there? Once I've replaced the faulty isolation valve can I just refill the boiler using the filling loop until the pressure is back to one and job done?

I noticed there is a big red valve further up the pipe between the faulty valve and the boiler which is currently turned to 5. I haven't been able to find much info about this valve, if I turned it to 0 would that stop the water coming from the boiler? In which case I wouldn't need to drain it.

Thanks for any help.

Browntoa

a repeat of your earlier thread on the same subject ??


https://forums.moneysavingexpert.com/discussion/comment/69644208#Comment_69644208

hdarren

No. I actually have the replacement valve now and attempted to replace it. I assumed no water would come from the boiler since it stopped leaking when the pressure was at 0. So got a little jumpy once water started pouring from it.

Rubidium

hdarren wrote: »

No. I actually have the replacement valve now and attempted to replace it. I assumed no water would come from the boiler since it stopped leaking when the pressure was at 0. So got a little jumpy once water started pouring from it.

The system pressure may well be at zero but there is still a heating system full of water e.g. upstairs radiators provide a head of water and the water will obviously drain out.

hdarren

But the boiler is upstairs above all the radiators.

Rubidium

Change the bloody valve and re-pressurise - you can't make an omelette without breaking some eggs!

hdarren

Welp. I drained the boiler, not a lot more water came through. I switched the faulty valve with the new one and started pressuring the boiler via the filling loop. Got to about 0.5 then noticed a small water leak dripping from the bottom of the boiler! Had to drain the boiler again...

Guess I'll have to call a plumber after all.

macman

Not a plumber-you need a GSR RGI. Plumbers are not competent to work on gas appliances.