R-22 replacement?

[Ed Pearlstein]

Is there a drop-in replacement for R-22? If so, can it be used to
"top off" a home AC that has R-22 in it?

[George Goble]

In article <3t3vvq$o...@crcnis3.unl.edu> e...@unlinfo.unl.edu (Ed Pearlstein) writes:
> Is there a drop-in replacement for R-22? If so, can it be used to
>"top off" a home AC that has R-22 in it?
>

Propane. But you must assume the responsibilty and liability for
the flammability. I friend of mine has run pure propane in 2 or 3
window A/C's for 4-5 years now.. still running fine.
A typical split home system holds 5lb of R-22, which is equiv to
around 2.5lbs of propane.. How many people get nervous with
3 1lb propane torch gas bottles in their garage?
Make sure you put a drier on or dry it first. Most propane is slightly
"wet"..

The averge female might have almost that much propane in the
propellants of the various products she has in her bathroom.
--ghg

[n7...@primenet.com]

In <3t4kct$l...@mozo.cc.purdue.edu>, g...@cidmac.ecn.purdue.edu (George Goble) writes:
>In article <3t3vvq$o...@crcnis3.unl.edu> e...@unlinfo.unl.edu (Ed Pearlstein) writes:
>> Is there a drop-in replacement for R-22? If so, can it be used to
>>"top off" a home AC that has R-22 in it?

What is the need for a drop-in replacement? R22 will be manufactured for
many more years and is not subject to the penalty tax like CFCs.
Changing refrigerants is never a drop-in procedure. Another product may be
close in temp/press or enthalpy, but then oil compatibility, weight of new charge,
flow rates etc etc.
Propane meets most of those. I would not like to be the next serviceman to
apply a torch to a system with propane in it. I have such systems where I work and
fortunately they haven't need repair.

Jim

[George Goble]

In article <3t68ct$5...@panic.primenet.com> n7...@primenet.com writes:
> Propane meets most of those. I would not like to be the next serviceman to
>apply a torch to a system with propane in it. I have such systems where I work and
>fortunately they haven't need repair.
>
> Jim

Good service technique means using dry nitrogen or equiv flowing
through a system when brazing. Propane needs to be mixed with
92-98% air to "burn".. Purge with dry nitrogen through and no problems.
As long as the system isn't full of air, there will be no
"internal" explosion even if still full of propane at 1ATM pressure.

We use isopentane (flammable hydrocarbon), boils at 75F or so,
in place of R11 for flush to clean up burnouts.. As long as one
is aware of the dangers and takes appropriate precautions, no
problems. (dry nitrogen purge, vent the flush outside, no sparks,
fire, smoking, etc, in the area). $450 buys a 55gal drum of it
(grade "pure").. Sure is cheaper than 11.

The movie industry has greatly warped the public's perception of
flammables and explosions. Cars (in movies), usually have waterbeds
in the back seat & trunk filled with gasoline, and a couple of sticks
of dynamite to "disperse" and mix with air, to cause the
conflagerations so commonly seen. Pressurizing a refrigeration
system with oxygen by mistake, will usually make a mess as bad
as seen on the movies though.
--ghg

[n7...@primenet.com]

>Good service technique means using dry nitrogen or equiv flowing
>through a system when brazing. Propane needs to be mixed with
>92-98% air to "burn".. Purge with dry nitrogen through and no problems.
>As long as the system isn't full of air, there will be no
>"internal" explosion even if still full of propane at 1ATM pressure.

In 13 years of service work for 6 employers, I have seen N2 used only twice.
Here at my present job and in school. Not saying this is good, but N2 in the field,
residential and commercial service is rare.
The new refrigerants and oils will probably change this since it is much better at
cleaning scale from the tubing walls.
One additional thought, some areas of the system don't get flow and retain
some refrigerant. I've seen lots of green flames while brazing a system that was
drained (no N2 was used though).

Jim