Calorifier PRV rating

[Rob-M]

The PRV on our calorifier has started to continually drip, I've given it a few twists to try clearing any scale but this doesn't appear to have resolved the drip. If I am to replace it how do I know what pressure rating the new valve needs to be...?

[PeterDHS]

You should have a label on the calorifier which states the max operating pressure, and you 'should' know your pump cut-out pressure... or can find it easily from a web search. Add a bit to this for heat expansion.

 

Almost invariably the answer is 3 bar.

[pearley]

Our old calorifier had a 3 bar prv. The new one, a Surecal, came pre-asembled with a 4 bar one.

[raymondh]

As above surecal 4 bar

[Tony Brooks]

But as long as the pump cut out below 3 bars a 3 bar PRV will work just fine. The important thing is not to exceed the calorifier's pressure rating.

[OldGoat]

A well known hire company remove the 4 bar PRV supplied with the calorifier and replace it with a 3 bar one.

There must be a good reason...

I know 'cos I bought one of those 4 bar types as an emergency from then for a nominal sum....

 

IMO, it's not so much a matter of matching it to the pump - but to protect the tank from over pressure when heating up from cold....

[Rob-M]

Thanks for the advice, I'm not sure of the make so I will have to check for a label when next at the boat.