replacing double check valve on combi filling loop ??

[doyler]

Hello,

Would really appreciate any advice...

The double check valve on the boiler side of the filling loop of my combi system (gas fired, baxi combi 80e boiler) is leaking (drips about a quarter of a pint every 48 hours). The valve has a screwdriver slot on it which I have tightened but it still leaks. Pressure is 0.5 bar and before I repressurise I want to fix the leak. Should I

a) leave the filling loop permanently attached and assume this will block the leak?
b) replace the valve?

If b, I'm assuming I'd have to drain the system first, then replace valve, then fill up the system adding inhibitor... seems a lot of work to replace one leaky valve! Or is there a simpler way?

Any help appreciated!!

 

[Breesey]

Replace the valve, assuming the valve itself is leaking and not its connection to the primary (sounds like it leaks thru the valve?). Are you sure its the valve itself that leaks? The filling loop should not be left connected anyway btw.

If you need to drain down enough to allow access to the valve, depending where your boiler is in the sytem (high or low) you may not have to completly drain.

 

[doyler]

Hey, thanks for speedy response!

> Are you sure its the valve itself that leaks?

Yes, it drips from the end of the valve, not at the connection to the pipe.
Perhaps I could simply screw on a cap or a stop valve in front of the leaking valve to block the leak? (At present there's no stop valve on this end of the filling loop.)

If I'm going to replace the valve, is the correct procedure as follows?

1 isolate the radiators
2 open the drain tap inside the boiler, drain until water stops flowing
3 remove faulty valve (expect a little more water to come out)
4 attach new valve
5 re-fill system using filling loop
6 open the radiators to allow flow
7 add inhibitor somehow

Has anyone used the 'rustbuster' to add inhibitor via the filling loop? Does it work?

 

[Breesey]

The double check valve should be replaced if it is leaking, it is there for a reason!


You need to turn the boiler off and drain down, far enough for the DCV to be 'dry' and then replace it.

You can put the inhibitor in before you install the new DCV, by any means you fancy!