leak detector

Hi all, I really need to find a leak. I'm having problems with finding this particular leak on a VRV system. I have just started to pressure test this for tighteness but before we can get that we need to evaluate where the leak is.
I've tried listening and going over bubble test at the flares, but theres some hidden pipe brazes above plasterboard ceilings I cant get to yet.
What I need is a cost for an ultrasonic leak detector if any body knows a good one recently purchased.
Its either that or using trace helium or hydrogen with OFN & getting a detector for these gases specific to trace. I know this system dropped 10bar over night & its a 'Mare' to find the leak.
Who knows that if using the ultra sonic one will direct me to the area quicker? before I have to cut out the ceiling to get at the joints to locate?
Any help appreciated
Regards Dellapureneed

You could rent one for this one-off job perhaps?

http://www.ashtead-technology.com/uk...ltrasonic+leak

split the system and pressure test with helium and nitrogen ie condenser only,then pipework to bc box then each branch to indoor units-get flare plugs and get loads of leak spray- 90% of the time its valve caps on the oudoor unit or bc valves or a cracked flare. 10bar overnight should be easy to find as there should be oil stains! good luck

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Originally Posted by install monkey

split the system and pressure test with helium and nitrogen ie condenser only,then pipework to bc box then each branch to indoor units-get flare plugs and get loads of leak spray- 90% of the time its valve caps on the oudoor unit or bc valves or a cracked flare. 10bar overnight should be easy to find as there should be oil stains! good luck

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Seems to be the sensible way, logically isolate and do a drop test on sections of the system. Split the system into near 50:50, then test and proceed by process of ellimination. Then split the faulted section again into 50:50 and so on. Much quicker than tracing around the whole system.

good luck.

Also: Moral of the story - always pressure test before hidden pipework is hidden.

I know this wont help you out much ,but i have found on large vrv/vrf installations the best course of action is to test as you go,ie. if you have a system split across floors for example test each floor before connecting to the main line on three pipe systems and on two pipe systems such as mitsu test main line before connecting to bc/indoors.
A 10bar drop over night is a big leak,,try access the site out of hours . less bodies = less noise
Might have a better chance of hearing it.
If it's a new install there wont be any oil stains !!
Best of luck
Stu