<VV> AC Leak Question

[Britt Griffith]

There's nothing better at finding small leaks than the dye/ultra-violet
light units. Johnstone Supply and Grainger sell them in California. Buying
one will "lighten" your wallet pretty good. You'll also have to buy the dye
and charging cartridges if they don't come with the unit.

For the dye to work, you will have to charge it into your A/C system with
refrigerant. Then, you'll have to operate the A/C for some time to
distribute the dye to all the interior surfaces. Finally, you just have to
sit back and wait for it to leak out with the refrigerant and the oil.

Before throwing a lot of money at this high-tech leak detection method, I'd
strongly suggest you put in some low-tech investigation first. Inspect each
section of the system and look for dirty, oily stains on the condenser and
evaporator fins. Both of these coils are 40 years old and have gone well
past their designed service life. Look at the hoses and every clamped
fitting and mechanical coupling you can find, even the ones on the expansion
valve in the evaporator and in the tunnel.

In 25 years of refrigeration work, I've found more leaks using soapy bubbles
than any other method. After you've looked things over and found some
suspect areas, charge up your system with nitrogen (60 psi is plenty) and
check out these places. Also, look carefully at the high and low pressure
hose fittings to the compressor, since they were undone and tightened when
you put the rebuilt unit in. One other thing to check is the schraeder
valves. Take your charging hoses off of the access ports and soap them up
while you have pressure in the system. A lot of times these cheap little
valves will not seat properly and refrigerant will slowly leak past them and
the caps that cover them. I know that the caps have seals or o-rings in
them, but they don't always work.

-----Original Message-----
From: LanningWB at aol.com [mailto:LanningWB at aol.com]
Sent: Thursday, June 30, 2005 3:29 PM
To: virtualvairs at corvair.org
Subject: <VV> AC Leak Question


I have a '66 Corvair with factory R-12 system that has leaked down and I
want to find the leak.  A rebuilt compressor with a new seal was installed
last
year.  The system was recharged then and seemed to hold the  charge over the
summer (at least it cooled all summer).  Over the winter  the freon leaked
out.

I pressurized the system with nitrogen to 60 psi.  In 24 hours it  leaked
down to about 35 psi.  I tried to find a leak using soap with  no luck,
however I
have not pulled the pulley to check the seal.

Does anyone know anything about the flourescent dye that AC shops use with
a
black light to find leaks?  Does it work good?  If so, where can I  get it?
Or is there a better method to find the leak?  BTW, I have an  MVAC license
so
I am "legal" to work on the system.

Tx, Wade


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