Vaillant Boiler Won’t Repressurise

[Catalina]

Hi Everyone, was just hoping for some advice regarding pressurising a boiler. I have a Vaillant Turbomax, not 100% sure exactly what model but it’s about 20 years old now.
My boiler pressure has reached 0.5 Bar so I thought I should open the internal filling loop and repressurise. However when I opened both valves (through 90 degrees) there was no sound of rushing water, as with the previous times I have done it.
I have attached a photo of the entire underside of my boiler and a close up of the valves to show they are both turned through 90 degrees. I have also attached a photo of the inside showing the braided hose.
I know my mains pressure is good, so I just wondered if anyone had any suggestions of what might be wrong or any possible fixes before I call someone out. I still currently have hot water and central heating, but probably not for much longer.
Any advice/ tips would be great. Thank you so much.

 

[CBW]

Could be a blockage at the heating flexi end or a failed filling loop valve. I suppose it depends on how often they’ve been opened.

 

[Catalina]

Thanks CBW, I typically would repressurise 2 maybe 3 times a year, keeping it around 1.5 Bar. So they weren’t frequently used.
Would this be something I could fix or at least look at? I was thinking of unscrewing the braided silver hose and trying to clean that out, see if it was full of ‘sludge’. Not sure exactly where the filling loop valve is, any ideas how I could check for failure.
Thank you very much.

 

[jurassic sparkk]

Could be that the nrv (non return valve) is jammed.


Unscrew the filling loop, with the valve turned off and gradually open the valve and see if it lets water pass.

 

[Catalina]

Hi Jurassic Sparkk, thank you. Just to be clear (so, knowing me I don’t do anything stupid) should I unscrew one or both ends of the silver hose and then slowly turn the valve through 90 degrees? And see if water begins to flow or have I misunderstood?
Thank you, sorry for the silly questions.

 

[jurassic sparkk]

Just unscrew the filling loop nut with the valves turned off. (Make sure you unscrew the fitting that connected on the larger pipe.) Then put the flexi pipe in a bucket or something and gradually (slowly) turn on the valves.

 

[Catalina]

So, done that, and after barely opening the valve water started literally gushing out. Turned the valve back off and reconnect the filling loop. Guess it’s the non return valve as you suggested. Can this be unjammed or does it need replacing?
Thanks for your help this afternoon.

 

[jurassic sparkk]

Send a picture of the pipework beneath the boiler.

 

[Catalina]

I have attached the underside of
The boiler and the other end of the filling loop. I hope they are clear enough.

 

[terryplumb]

Almost certain to be the check valve stuck closed and needs replacing.

 

[Catalina]

Thank you Terryplumb, this is probably a really stupid question. But which one precisely is the check valve, I will try and buy a replacement before I call out an engineer. Just want to make sure I get the exact right part.
Thank you.

 

[terryplumb]

It's the brass fitting on the end of the silver hose, next to the pump.

 

[Catalina]

This should be fun to access, there is literally no space on either side One thing after the other.

 

[terryplumb]

Yes ,not the easiest of access !!

 

[CBW]

Some side panels can be removed, unsure about yours