Isolating Radiators Part 2 - Mystery Pressure Drop

[Mike Jackson]

Dodgy expansion vessel?

No. The leak is definitely in the downstairs pipework. people are making this over complicated. If the system is fine when the valves to downstairs are shut but leaks when they are open it's going to be a leak on the downstairs circuit. As has been suggested above, disconnected this section and separately pressure testing will confirm.

 

[Geyser]

I had a similar problem once. Turned out a rad had been disconnected and valves built in under floor. Every time I went pressure test would be fine but overnight temp would drop and trv open. So happy when I found it!! Check outside for leaking drain off valve, apart from that you've had good advice. Wet test and find that pesky leaky joint..

 

[SimonG]

No. The leak is definitely in the downstairs pipework. people are making this over complicated. If the system is fine when the valves to downstairs are shut but leaks when they are open it's going to be a leak on the downstairs circuit. As has been suggested above, disconnected this section and separately pressure testing will confirm.

Sometimes it is the obvious.

 

[happyflyer]

LPC,

You must be dead dedicated or the Poirot of the plumbing world

 

[RoryD]

I would have thought that if all is well when downstairs is isolated but not if it is open..it has to be a leak there regardless of the test. PRV or leaking through the condensate would happen whether just upstairs on or the whole system on. Good Luck