How to refill my boiler

[rjw234]

Can anyone help with how to refill my boiler? It’s a Worcester 40cdi and pressure is low after bleeding some radiators.
I assumed it would be the braided hose in the picture, but adjusting the black valve and/or the silver screw on those doesn’t seem to do anything?

 

[Jajodu]

That should work, when you rotate the black plastic tap make sure the spindle also turns. Quite often the handle breaks internally.
From your picture they are both shut.

 

[rjw234]

Have opened both - per picture attached - and can’t hear any water going in, or see any change in pressure gauge. Have also checked that the spindle is also turning (ie black tap is not broken)

 

[Madrab]

Looking at the arrow on the ISO then it may be pressure reducing valve (PRV) is connected to the mains so , open the PRV to say around 2 bar. Then you'll turn the ISO valve with the screwdriver slot so the slot is in line with the valve, that's it open. Then slowly open the black valve until the system fills, then close it all down by doing the reverse.

 

[rjw234]

I presume the PRV is the one below (/on) the gauge? Have tried adjusting that and it doesn’t seem to do anything.

 

[Jajodu]

The black tap looks like it has cold mains pressure, remove the braided hose there and very slowly open the black tap, does water come out? Have a towel handy

 

[Madrab]

I presume the PRV is the one below (/on) the gauge

Yes, that's the issue, that valve doesn't seem showing any pressure so that needs to be sorted so it shows pressure.

 

[Madrab]

The black tap looks like it has cold mains pressure, remove the braided hose there and very slowly open the black tap, does water come out? Have a towel handy

You wouldn't normally have a PRV, running the wrong way on an filling loop inlet to a CH system. The pipe (black valve) runs down to the connection for the EV @ the pressure relief valve coupler. That would be a typical area to connect the loop to fill the system.

 

[rjw234]

Thanks for the replies - all working now!

I removed the hose and slowly opened the silver screw (with a towel handy!) and water came out. Figured the black valve must be blocked / not opening properly so had a play around with that (took plastic off, turned spindle back and forth, poked something in the end to try and clear any blockage…) then reconnected and it worked.

 

[Madrab]

poked something in the end to try and clear any blockage…) then reconnected and it worked.

Probably a Double check valve inside it, white plastic internal? The check valve was probably stuck and a poke has freed it.