Vaillant Boiler Won’t Repressurise

[Catalina]

@terryplumb Haha indeed. Last question I promise, any idea what size it might be, bearing in mind the boiler is probably 15-20 years old, I’m thinking probably 15 mm.
@CBW Thanks, I’ll check that out, I’ve never checked before.

 

[terryplumb]

Very likely 15 mm. Can you take a picture from above ,birds eye view ,in focus ?

 

[CBW]

I’d say 15mm as the flexi looks 1/2”. Failing unable to replace internally, I’d be fitting an external one.

 

[Catalina]

Apologies these were the best I could get. Hope they help, the hose has a width of 12.5 mm, so yeah about 1/2 inch.

 

[terryplumb]

That check valve doesn't appear to be a "standard" compression fitting ,and Probably has flat faced ends ,with rubber or fibre washers.

 

[Catalina]

Oh dear, that doesn’t sound good. Do you think it will be difficult to replace? I was going to get another 15mm one.
Also, if I unscrew the filling loop, will water come out or do I need to shut of my mains supply first.

 

[terryplumb]

You would need to drain the boiler / system water before removing the check valve. Sourcing a check valve with flat faced ends shouldn't be too difficult.
You could of course get a genuine manufacturers replacement.

 

[Catalina]

Thank you very much, I appreciate all help this afternoon. I wasn’t going to remove the check valve itself, I was thinking of unscrewing the silver hose from the valve itself and maybe seeing if I could ‘clean it out or reset the spring’. Was worried if I took the hose off, water might spray out. Although it’s probably a waste of time anyway haha.

 

[terryplumb]

I thought you had already unscrewed the hose when you told us water flowed out of the hose ,or did I misread your earlier post ?
Unscrewing the hose from the check valve shouldn't result in water flowing out from the valve ,but it may do if you started poking things into the valve !

 

[Catalina]

Ah sorry my fault, I didn’t explain very well. So earlier I unscrewed the hose but from the other end, then I turned the water on and it came out. This time I was going to unscrew the hose but this time from the check valve itself giving me access to the inside of the valve if that makes sense. But if I’ve unscrewed it from one end and no water came out then it shouldn’t matter which end it’s unscrewed from I suppose. But as you say, poking around inside the valve probably isn’t a good idea.

 

[terryplumb]

Doing what you did has proved the isolation valves are ok and passing water, but doesn't prove the hose is ok ,not blocked ( which is highly unlikely to be frank, but a remote possibility I suppose)

 

[Catalina]

When I unscrewed it earlier I stuck some wire through it. So I don’t think it’s blocked, sadly that would’ve been to easy haha