leak sealent in a can......

[gwm121]

I have a 12.5 kw r410a system which we were asked to look at and loses gas after 4 months, just enough by that time to effect preformance slightly, not enough to produce fault code, I have told the customer they have to have the gas reclaimed and system stopped till leak found (which would stop and fold their business) suction pressure doesnt drop much, but then the modern systems electronics will ask the inverter to work a bit harder and mask the problem.

We are told Torr tests and short (1 hr) pressure tests by others apparantly have shown nothing, and a 24 hr test of sections is out of the question for this particular site. No other company has been able find the leak. The last company apparantly reclaimed gas pressure and leaktested, found ok, recharged, and the system worked fine... for about 4 months.

hrp sell a leak sealent in a can, my question please is for someone who has actually used this, does it work and could it interfewre with capilleries elec exp valve etc. Could we still comply with law if we use this, in that we wouldnt be sure system leaktight before gas recharged, except that presumably a 1 hour nitrogen leak test wouldnt show leak.

Please dont tell me the standard ways to test, some leaks are seriously difficult ti find... maybe it is on a hidden part of the evaporator coil, maybe it is a flare that only leaks under certaing temp press combinations. There is uv dye in the system, no trace, sniffers show nothing.

[Tayters]

I have told the customer they have to have the gas reclaimed and system stopped till leak found (which would stop and fold their business)...

Good advice but crikey, what type of business are they in? What would they do if the compressor packed up?

does it work and could it interfewre with capilleries elec exp valve etc...

Anecdotal evidence suggests it's not a miracle cure. Depending on system condition others have found it to block the insides up. Some info on this thread: http://www.refrigeration-engineer.co...alent-in-a-can......

Could we still comply with law if we use this, in that we wouldnt be sure system leaktight before gas recharged...

As far as the law goes, I think so. Even if you didn't use it, a pressure test, vac rise test and subsequent sniffer test on recommissioning would satisfy the requirements I'd have thought. Rightly or wrongly the system appears leak free when be restarted so you could argue the point if you got pulled up on it.
Common sense wise though you would know it isn't leak free from its history. The leak sealant is a last ditch attempt beacuse the customer doesn't want it turned off and worked on long enough to find the leak.

Bottom line is it needs a longer pressure test (i.e. overnight) before contemplating the leak sealant.

Good luck mate. Nothing like a hard to find leak to make you feel like an rookie!!
It's not one of those double fan Daikin outdoor units by any chance?

Cheers,
Andy.

[install monkey]

for a 12.5 kw system it will hold more than 3kg of gas so ur expected to keep an f gas record sheet, also any repairs to the circuit will req a retest within 1month-also the records will indicate a problem- glo-stick it- then run it and go over it with a uv torch

[james10]

You could try helium, expensive though if you need to buy the kit

[chillerman2006]

Could we still comply with law if we use this, in that we wouldnt be sure system leaktight before gas recharged, except that presumably a 1 hour nitrogen leak test wouldnt show leak.

Hi gwm

as install has said, you have an history of leaking that has not been rectified, I would think that putting this system back into service without finding the leak, how ever hard to find, will be breaking the law

as James said go for helium, the difference in molecular size against refrigerant/nitrogen is like compareing beach balls to size 5 footballs (automic mass of nitrogen is 14 & helium is 4) .... if you still can not find the leak with leak fluid, you will need to use a mass spectrometer and for a totally leak free system to the smallest molecules that exist you can now get a helium/hydrogen mix.... (automic mass of hydrogen is 1)

R's chillerman

[charlie patt]

sealant in a can just dont bother its a waste of time unfortunatley if room is that critical the customer needs to make a choice prehaps a second back up unit whilst repairs are being completed but it sounds like a split test is required to isolate leak and conclude repair if its a daikin split test the condensor. i have found the sealants just hinder progress in the future and if its been gased that much that oil is ridden with moisture anyway

[al]

Forget the leak sealant, even if forced to use it you must put it into a leak tight system. A company here used it on their fridges and freezers, i've replaced 4 compressors so far and have multiple blocked capillaries. Maybe add more dye, with the leaks and top ups it may be diluted, can you run new interlinking pipe work to eliminate install issues?

al

[chemi-cool]

Best sealant is, good frares, tight nuts. Leaks are many times on the condenser manifold.

3kg in 3 months is a big hole, My thought is, the high side, pump it up with nitrogen , find the hole and repair it.

[Plank!]

What is the application of the unit?
Are any organic solvents or chemicals used nearby?

has me thinking ants nest corrosion...

[lowcool]

hydro static test the coils.if using leak seal fit an ample size drier for moisture air can still affect this stuff if trapped in the system