high combi pressure

[willsniffer]

have a combi which gains pressure from 1 bar to 2-3 bar overnight and have to release pressure. Suggestions so far include removing flexible loop ( is this easy??) or leaking diverter valve (?). Any thoughts - it's a vokera. Cheers

[chris French]

In message , willsniffer writes

My first idea would be that there is a small flow of mains water into the system gradually increasing pressure.

Techinically the filling loop is supposed to be disconnected anyway - that's why you have one.

It's easy enough to remove, just undo one end of it. If it's is leaking a bit of mains water into the system when shut then it will probably still be leaking a bit when is connected to arrange something to collect the water. If that is the problem you would need to replace the valve at the mains end.

[Christian McArdle]

It will probably one of two things.

1. A leaking (or partially open) tap on your filling loop. These must be kept disconnected, but almost never are. If disconnecting it shows the tap to be leaking slowly, it must be replaced. (It might just not be turned off).

1. A leak in your heat exchanger. This allows mains water from the DHW side to cross into the primary circulation water in the combi DHW heat exchanger (or DHW cylinder as appropriate). This is more serious and expensive, but MUST be fixed immediately.

Christian.

[Ed Sirett]

See below.