pressure failure

[coggins]

I have a worcester 240 cbi, when i run the hot water tap it stays hot for a few seconds and then goes freezing cold, and the pressure returns to zero. I have tried topping up the pressure but that does not work, any help please?

 

[bengasman]

Can you elaborate on that?

 

[coggins]

Can you elaborate on that?

yes I turn on my hot water tap and it goes boiling hot then freezing cold, and the pressure gauge drops to zero.

 

[dpsservices]

 

[bengasman]

Does the pressure go up when you turn it on? If so by how much?

 

[coggins]

Does the pressure go up when you turn it on? If so by how much?

yes it goes up to 4 or 5 max and then to 0

 

[bengasman]

Maybe you should try filling the boiler before turning it on.
The pressure gauge should be at 1 - 1.5 cold.
Set boiler controls at 1 for the time being.

 

[DazzarGaz]

Any water coming from the PRV outside?. Sounds like the expansion vessel is burst. If you check the air valve on the expansion vessel, you should be getting air coming out. If you get water this proves the vessel is burst and needs to be replaced.

 

[Agile]

Or read thre FAQ on this site first to see if your problem is already covered ( which most already are! )

Tony