Combi sys losing pressure every 2 days 4 months but no sign of leak

[Phill Listening]

Combi boiler system losing pressure every 2 days. We've been topping it up for months now and have had various radiators replaced and flooring pulled up downstairs around each of the radiators but so far no leaks have been found.

I'm at a bit of a loss of where the leak can be because given the amount of water we must have put into the boiler I assume we'd see it if it were on one of the upstairs radiators given the 50 or so times we must have topped up the boiler.

We even had a gas plumber pressurise and seperate the boiler and system yesterday who kept the boiler at 2.2 bar and the pipework connecting the radiators at the same when the system was cool. After 2 days the pressure on the radiators was just over 0.5 bar and the boiler had remained the same.

I'm considering putting perfume into the system after a youtube suggestion by skillbuilder but I'm not sure what good that might do if we're topping it up within 2 days (the suggestion was to let it run for 2 weeks to circulate).

Does anyone have any good suggestions on finding the leak?

 

[Deleted member 120897]

So if I read this correctly, you have a pressure gauge for the boiler and one for the radiators? Can you inform us of the system you have, Combi, unvented cylinder etc.

 

[ShaunCorbs]

Probably looses pressure when it’s hot