Vented system - no hot water

[TonyBronx]

Hi All,
I hope you are well. I have a vented system with an immersion cylinder, old school boiler not a combi boiler.
I think it is the 2nd hottest day in UK and I wonder if there is any relation to my system giving up at this moment.
I did also take a decent bath yesterday.

The cold water is there and a decent pressure but I lost hot water.
Checked the water tank in the loft and it is empty and dry.
Ballcock/float valve does nothing when I move it up and down, no water coming out.

Is this valve I should replace or is there anything else I should check?
Please advise

Thank you

 

[ShaunCorbs]

Any valves you’ve turned off ?

 

[TonyBronx]

Any valves you’ve turned off ?

I haven't touched any valves recently. The valve before the float valve is in open position.

 

[snowhead]

If it looks like this, a part 2 valve then,


Either the diaphragm washer in the float valve has hardened,



Or there's grit in the orifice

 

[TonyBronx]

If it looks like this, a part 2 valve then,

View attachment 96412
Either the diaphragm washer in the float valve has hardened,

View attachment 96419

Or there's grit in the orifice

View attachment 96414

Ok it looks like the "pin" was stuck due to some mineral deposits. Treated in place with a vinegar solution to dissolve it.
So far so good. Will see how long it will last. Rather a quick fix, perhaps better if I took it off and submerge a whole piece in a vinegar solution.
Thank you