HELP: Pressurised/Unvented cylinder - No hot water, central heating works fine

[bacon_sandwich]

The safety valve aka pressure relief valve appears to be there (red thing) but if it does in fact relieve itself it will discharge water directly into your house roughly south of the red valve. It is supposed to discharge water outside (in a safe manner, i.e. so not to scold anyone ), also there is supposed to be a device below the red thing so you can visually check for evidence of discharge. Your property is currently at risk from water damage as is.

 

[Rob Foster]

yea is that prv just open ended or IS IT CAPPED OFF ? I worry
both are wrong capped off is really bad

 

[Best]

yea is that prv just open ended or IS IT CAPPED OFF ? I worry
both are wrong capped off is really bad

That is a bloody good point!
I think looking at the last photo that the P&T relief valve has the internal compression nut showing and hopefully it is not a 1/2” blanking plug.

 

[bacon_sandwich]

eeekkk, best op take a blow up of the PRV for us to muster. Never seen a blanked off PRV (whats the point) ,so it would be a first....

 

[ShaunCorbs]

It's not blanked off it's a nut and olive but the nut is externally threaded

 

[Best]

eeekkk, best op take a blow up of the PRV for us to muster. Never seen a blanked off PRV (whats the point) ,so it would be a first..

I have seen one brand new unvented install that the plumber screwed a small lever valve directly into the pressure relief of the combination valve (which was also installed near base of cylinder). He also joined the D2 at tundish to 15mm copper and just run it out through wall at first floor level. Bizarre.
I think I read somewhere that unvented units sold in U.K. must come from factory with their P&T relief valve already fitted on cylinder. I suppose this is to ensure they are safe from exploding to make them idiot proof.