Finding Leaks

[markmast]

I have only been in the trade for 2 years and i am wondering how everyone goes about finding leaks in an A/C system, i find alot of times its in the Evap coil so i pump the refrigerant into the condenser and pressurize the lines and the evap, if that is leaking i go use soap to pinpoint it and fix the leak or repair the coil, if it does not lose pressure the leak is in the condenser and i will leak check it with an electronic leak detector, please let me know how you leak check systems, i dont really like having to leave a system pressurized with nitrogen overnight sometimes just to find out if the evap is leaking or not

[Jabarco]

a wealth of refrigerant leak detection methods.
http://www.bacharach-training.com/methods.htm

Jabs

[cem-bsee]

soap will only find GROSS leaks
get a test instrument -- "tuned" for the paticular gas you need to check --

[Rusty199]

Unfortunately, I have no luck finding leaks with an electronic detector. I have tried a few and get lotsa false readings.
The best methods seem to be:

Look for the oil staining.

Inject with UV dye and leak search next season if it's a small leak.

High pressure nnitrogen and trace R22 if it's a larger leak.

These seem to be the best for me. I carry equipment for electronic, ultrasonic, nitrogen, foam and ultraviolet searches. So I've done a few...

[markmast]

Thank you for your replies, the website was great!
and unfortunatley i dont have ultrasonic leak detection equipment available to me through my company (so until i can afford it!!) but as far as the nitrogen with trace gas of r22 is that what you pressurize the system with when using an electronic leak detector?

[markmast]

i have also been told that if you isolate the evap coil and that is whats leaking the best thing to do if its a small leak is just pull the coil, pressurize it and dunk it in water, look for bubbles to pinpoint the leak what do u think of this procedure?

[JstTrkin]

Nitrogen and R-22 would be used with an electronic leak detector, nitrogen being a lighter gas will escape faster then refrig alone.

I've never used the dunking in water method, sounds like a lot of time involved, but I'm sure it would work fairly well if you knew exactly that the leak was somewhere in the evaporator. Thats a big bucket to carry around or hopefully the customer has a pool with a hot daughter or something floating in it.
I mainly use UV dye in my systems if I cannot find anything with the electronic leak detector. I've read some posts about voiding compressor warranty's but with around 5yrs of using the stuff haven't had a single problem.
As far as the ultrasonic leak detection goes, save the money I've found mine pretty much useless.

[markmast]

Thanks for the reply, i will save my money on that ultrasonice leak detector i have heard alot of bad things about them! As far as dunking the coil, i start a new job next week and the one service tech at this company im going to was telling me about this method, it sounds pretty time consuming to me too but i think its only for small leaks, but if theres a pool and a hot daughter that coil is going under lmao! have a good one!

[cem-bsee]

water immersion is like soap -- good for finding gross leaks!

"gun" should find leak equating to 1 bubble per year in h2o pool --

[Rusty199]

Nitrogen is good for pressurizing the system to increase the rate of leakage while leak searching. R22 is added as a tracer gas for electronic leak detection. I have also pulled & dunked the evap coil, pulled the condenser and brought it into the garage for UV testing, disconnected and isolated the evap, condenser and line set to vacuum test seperately.

Most leak searches are time consuming, and sometimes you still don't find it. Unfortunately, the easiest method, the UV test, is the slowest because the longer it's allowed to run (and leak) the better it works. I find many at the end of the season or the next spring.

I've never heard anything about warranty issues with UV dye, and I've never had a problem in the 9 yrs or so I've been using it either.

I also agree with not wasting your $ on ultrasonic equipment. I use it, but it's no magic wand either. They pick up every sound like road noise, wind, your own movement, chipmunk farts, etc.
My favorite trick for evap coil searches is to pressurize with nitrogen to 325 lbs and spray the entire surface with big blue (bubble solution) and then listen with the ultrasonic detector. Leaks sound like eggs frying in the distance, very faint. Then check the area for fine bubbles (like what we hayseeds usta call frog spit, that stuff that you'd find on plants).

Leak searches are HARD, but very few techs are good at it. Make it a specialty and you will become valuable in your trade.

[coolmen]

nitro and soap bubbles

[Airmechanical]

hopefully the customer has a pool with a hot daughter or something floating in it.

now thats what i call thinking positive!



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[Airmechanical]

its a good thing to have several types of detection methods, the more the better,

i carry nitrogen, electronic detector (not a waste of money), and soap bubbles, if i cant find a leak with those things

i would then isolate the system, in order to determine which component is leaking, then go from there

of course letting the customer know on small leaks it could get quite expensive to find!



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