Finding a leak on a R410a city multi

[HVAC Sid]

Hi there

having problems finding a leak on a r410a city multi using OFN. System will hold 32bar over the weekend but will lose 9kg in less than a week when running.

Im aware there is better methods due to the municles being bigger in the OFN than the refrigerant.

Many thanks

[install monkey]

check the bc box

[HVAC Sid]

already checked this, no sign of oil anywhere

[marc5180]

Hi there

having problems finding a leak on a r410a city multi using OFN. System will hold 32bar over the weekend but will lose 9kg in less than a week when running.

Im aware there is better methods due to the municles being bigger in the OFN than the refrigerant.

Many thanks

Sounds like you have a leak that only surfaces when the system is running and the pipes are vibrating or expanding/contracting.

A few years back I had the same problem which was finally traced to a nail head that had become lodged inside the pipework (which had been rested on top of it).
It was only when the system was running that the pipes must have slightly vibrated that the leak became visible.

Can you access or see all of the pipework to do a visual check?

[HVAC Sid]

thanks Marc starting too look like is the problem, have you used hydrogen are helium for leak testing and if so what sort of pressures should I be looking too test too

[marc5180]

thanks Marc starting too look like is the problem, have you used hydrogen are helium for leak testing and if so what sort of pressures should I be looking too test too

Helium is notoriously expensive but air products/BOC do a nitrogen/helium mixture but this didn't help either.

Unfortunately I'd suggest trying to get access to the all of the pipework.

[r.bartlett]

I never did track down the waitrose guy...

http://www.refrigeration-engineer.com/forums/showthread.php?38520-Scents

[Deano240]

I had the same problem it was the expansion valve inside a cassette

[jonjon]

Try uv dye

[install monkey]

oil sep on it-
degas it and pressure test using nitro/helium mix:p

Try uv dye