How do I repressurise this boiler?

[poppy101]

After bleeding some radiators, my Ideal Sprint combi boiler stopped working. Pilot is on but when there is demand on the system it does not fire up. From reading around I understand the problem is low pressure (should be 1-1.5, currently less than 0.5)

I'm trying to repressurise the system but I can't figure it out. There is a filling loop already connected up, with a tap, but when I turn the tap nothing happens - doesn't sound like there is any water going through it, and the pressure doesn't go up. There is a screwdriver valve on the underside of the other end but when I open it the water just comes out, it doesn't fill.

Pics:
http://imgur.com/a/hsYn0

 

[NeilWilliams]

Comes out of where, sorry? Could one of the connections just be loose?

Neil

 

[poppy101]

There is a screw on the underside of the end of the hose opposite to the tap.(third picture in the imgur link above) If I turn that screw halfway or a whole revolution, nothing happens. If I unscrew it further, water starts to leak out from around the screw.
http://i.imgur.com/GgjqAFN.jpg

 

[NeilWilliams]

Ah I see.

That screw is some kind of in-line valve - so if you open[1] both the screw and the tap (there is one on each end of the filler loop, so it can be removed - boiler installation instructions, or at least the ones for mine, tell the installer to remove it, but nobody seemingly ever does) it should pressurise the system.

[1] The screw valves like those are quarter turn valves - a quarter turn so the screw is in line with the pipe = fully on.

It's not unusual for those inline screw valves to leak a bit - mine do.

If it doesn't, either that isn't there for pressurising (though it looks to me like it is!) or something else is wrong, which is probably beyond my competence level to work out as I have little plumbing/heating experience beyond the basics.

Neil

 

[poppy101]

Don't think it's a screw valve. Seems like a double check valve. Regardless, when I open it and the tap it still doesn't fill.

 

[NeilWilliams]

You might be right - I forget what those valves were called, but either way turning the screw will turn it on/off, with the screw head being across the pipe being off, and along it being on.

Could the tap on the other end perhaps be faulty/stuck?

Other than that I'm a bit stuck I'm afraid. I would, in normal circumstances, expect opening both ends of that to pressurise the system - it does on an almost identical setup on mine (though with mine it's on the bottom of the boiler rather than separate it essentially looks exactly the same).

Neil

 

[denso13]

Close the white tap and remove the braided hose at the tap end. Does water come out when you then open the white tap?

 

[poppy101]

Close the white tap and remove the braided hose at the tap end. Does water come out when you then open the white tap?

Yes. Water is flowing normally out of the hose when the tap is opened

 

[denso13]

May be the check valve at fault then if it isn't letting water through. You could drain some water from the system and remove it to check.

 

[Madrab]

The water that is flowing out of the white tap when opened fully, does it feel like it's at mains pressure (same as say the kitchen cold water tap pressure)?
If so then it does sound like the check valve, the valve with the screw in it, might be jammed closed as denso suggests.

 

[poppy101]

May be the check valve at fault then if it isn't letting water through. You could drain some water from the system and remove it to check.

Yes, it was the check valve at fault. Got it replaced and all fine now. Thanks for the advice