Under sink heater

[darkside121]

Can I get some advice please.
10 litre under sink heater.
I have had an under sink water heater for the last year or so and all has been fine, then one day the pressure relief valve kicked in and started releasing the water. I thought it might be the valve that was broken so I replaced it, but this did not sort the problem.
In looking around it seems there should be a expansions vessel in the pipe work which there is not. So I am looking at fitting one of these and hope this will sort the problem.
But I have a concern, which is at the moment the prv is always loosing water not just when it heats up and the water expands.
So I can't under stand why I'm loosing cold water when the prv is 6bar and the mains is 4bar
I hope that make sense and the spelling in readable
Thanks for any help

 

[shray]

Are you sure it's a 6 bar prv and not a 3 bar ?

It doesn't necessarily need an expansion vessel, baring in mind it's bern fine up until recently. Put a pressure reducing valve on it to limit the incoming mains pressure especially as it has no relevance to the hot water.

 

[darkside121]

Are you sure it's a 6 bar prv and not a 3 bar ?

It doesn't necessarily need an expansion vessel, baring in mind it's bern fine up until recently. Put a pressure reducing valve on it to limit the incoming mains pressure especially as it has no relevance to the hot water.

Yes it's a 6 bar prv. Maybe I'll just try that first thanks

 

[buck51]

I was called out awhile back to a 6bar PRV blowing off,
It was in a school and the noise from the cold main throughout the school was deafening
It was in an area of high rise blocks and the pressure had been increase to just over 6 bar

Fitted a Pressure Reducing Valve on pipework to water heater, and no more problems

They dont normally just leak, they tend to bounce.