Newsgroups: rec.autos.tech
From: John De Armond
Subject: Re: R-12 Contamination
Message-ID: <-4y8-fa@dixie.com>
Date: Mon, 01 Aug 94 20:06:23 GMT

MARKMYERS@delphi.com writes:

>filter dryer had lost its contents (drying agent) into the system.  It has
>combined with the system fluids and has the consistency of grease.  Is 
>there any way to clean the system?  Is it going to be more expensive than 
>the value gained? The local shop doesn't have a clue on repairing it.

The traditional fix has been to flush such systems with R-11 but 
since that now sends the econazis into hysteria, not to mention 
that it costs several hundred dollars for the R-11, alternatives
are needed.  George Goble (of GHG-12 fame) has had very good luck flushing
contaminated systems with n-heptane.  The characteristics are similar
to R-11 with the exception that it is flammable so the flushing
must be done outdoors.  Not having a handy supply of heptane, I've
devised a method of using liquid propane.  I simply feed liquid 
propane from a 20 lb cylinder into the chunk of system to be flushed.
On the other end of the system, install a ball valve.  The ball valve
is the "expansion device".  Properly operated, liquid propane will
flow to the valve and flash to gas as it escapes.  You can either
run a hose from the valve to a safe place and have an assistant 
flare it off or dilute it with lots of air (I use a 36" chicken coop 
fan).  Propane is a very good solvent and will clean the system well.
Figure on tossing the compressor, as it will be eaten up by the 
abrasive desiccant.  Be sure to disassemble all fittings and look
for screens.  They can stick them in the darndest places.

Assuming you can do this work yourself, it is most cost-effective.
Even if you take it somewhere to be charged afterwards, cleaning
it yourself is very cost-effective.

John

From: ghg@freedom.ecn.purdue.edu (George Goble)
Newsgroups: rec.autos.tech
Subject: Re: R-12 Contamination
Message-ID: <31k4sf$q37@mozo.cc.purdue.edu>
Date: 2 Aug 1994 00:43:59 GMT

In article <-4y8-fa@dixie.com> jgd@dixie.com (John De Armond) writes:
>MARKMYERS@delphi.com writes:
>
>that it costs several hundred dollars for the R-11, alternatives
>are needed.  George Goble (of GHG-12 fame) has had very good luck flushing
>contaminated systems with n-heptane.  The characteristics are similar
>to R-11 with the exception that it is flammable so the flushing

It is actually iso-pentane.. boils around 77F or so like R-11.
About $450 for a 55 gal drum from Phillips 66, Borger, TX.
Propane would work also, but one has to keep it at enough pressure
so it does not get cold before it exits or it will not get
all the crap out.  Keeping up the pressure, usually means reducing
the flow..  Nothings beats R-11 (or isopentane), pushed thru
with 200 PSI of dry nitrogen for a good flush.  John, did you put
some nitrogen "head" on the propane to get the pressure up?
--ghg

Newsgroups: rec.autos.tech
From: John De Armond
Subject: Re: R-12 Contamination
Message-ID: <!-189#p@dixie.com>
Date: Wed, 03 Aug 94 03:04:00 GMT

ghg@freedom.ecn.purdue.edu (George Goble) writes:

>In article <-4y8-fa@dixie.com> jgd@dixie.com (John De Armond) writes:
>>MARKMYERS@delphi.com writes:
>>
>>that it costs several hundred dollars for the R-11, alternatives
>>are needed.  George Goble (of GHG-12 fame) has had very good luck flushing
>>contaminated systems with n-heptane.  The characteristics are similar
>>to R-11 with the exception that it is flammable so the flushing

>It is actually iso-pentane.. boils around 77F or so like R-11.

Sorry 'bout that.  brain fade, I guess.

>Propane would work also, but one has to keep it at enough pressure
>so it does not get cold before it exits or it will not get
>all the crap out.  Keeping up the pressure, usually means reducing
>the flow..  Nothings beats R-11 (or isopentane), pushed thru
>with 200 PSI of dry nitrogen for a good flush.  John, did you put
>some nitrogen "head" on the propane to get the pressure up?

nah.  Just did it the old fashioned way - a hot water hose washing down
the propane tank.  What I do when I use this technique is to allow
the propane to flow at a reasonable rate for a bit until I am sure
the whole system was full of liquid and then pop the ball valve 
wide open for a second.  The very high velocity gas/liquid mix 
seem to do a good job of sweeping everything out.  The worst system I
cleaned this way was an extremely severe burnout on a refrigerator caused
by a Green Plug.  This was the mother of all burnouts because the green
plug kept it cooking without tripping the thermal overload.  The 
odor almost nauseated me when I, er, recycled the old freon :-)
A couple of quick blasts as described with propane followed by an argon
purge (no N2 handy) revealed no odor and an acid swipe came up negative.

John

From: ghg@cidmac.ecn.purdue.edu (George Goble)
Newsgroups: rec.autos.tech
Message-ID: <3v4824$nc4@mozo.cc.purdue.edu>
Subject: Re: Repairing A/C again -- faulty rebuilt compressor .. or is it?
Date: 26 Jul 1995 02:08:04 GMT

In article <DCA7tA.ACB@twisto.eng.hou.compaq.com>
sravet@bangate.compaq.com writes:

>grep@cris.com (George B) wrote:
>>In article <3v1udm$6qp@panix2.panix.com>, kenbell@panix.com (Ken Bell) wrote:
>
>>>The system wasn't flushed last time because I was told that the
>>>"approved flush", R-11 (?), was no longer legal due to ozone-preserving
>>>restrictions
>
>>Your Federal tax dollars at work. You need some kind of solvent that
>>leaves NO residue. Good luck, R-11 was good stuff for flushing systems.
>>Not sure of any replacements available. Might look into CRC
>>'Lectro-Motive...it leaves no residue...put a couple of cans into the
>>condensor and force it out with air.

Anybody know what is in "CRC 'Lectro-Motive" ?


>According to MACS recommended service procedures....
>
>Flushing should only be performed with the type of refrigerant used in the
>system, and should be done in series with recycling equipment so that none
>is vented.  If you've got an R-11 recycler you could probably still use R-11
>to flush


Those weenie recycler "recirculator" pumps... I can urinate faster
than those can pump.. They dont get squat out (for oil).. maybe 1/2
of the oil?  what about the metal shards left over from a failed
compressor? .. sure MACS says use flow restricting filters, etc..
for cleanup.

The way I learned to do a "real" flush, was to use R-11
(boiling pt approx 80F), stays liquid thru the system..  - much
better than blowing out with air..

Disassemble the system.. remove compressor, drier, and the
expansion device.. Put severl pounds of R-11 in a BBQ grill
propane tank.. pressurize to 240 PSIG with dry nitrogen..
connect it up and blow some 11 through each segement, follow
by some dry nitrogen.. Kicks like a firehose.. no weenie
recirc pump.. That's a REAL flush.  System is left clean
and bone-dry (no oil) and ready to reassemble.

Today, we use Isopentane (GHG R-11 substitute?), boiling pt around
77F or so.. like R-11.. Bad news, it is a little more flammable
than gasoline.. have to take fire precautions (work outside,
disconnect battery, fire ext handy, etc).. but it still does
a hell of a flush. Leaves no residue, no ODP. It is also cheaper
than R-11.. About $450 for a 55gal drum from Phillips-66 in
Borger, TX.

--ghg
http://ghg.ecn.purdue.edu
http://worldserver.com/R-406A

From: ghg@cidmac.ecn.purdue.edu (George Goble)
Newsgroups: sci.engr.heat-vent-ac
Subject: Re: Contaminant Removal
Message-ID: <4r0a50$lcp@mozo.cc.purdue.edu>
Date: 28 Jun 1996 09:54:40 GMT

In article <4r0729$7db@news.enterprise.net> davida@enterprise.net
(davida@enteprise.net) writes:

>This information should fill in the blanks I left in my previous post
>and give some idea of the steps I intend to take.
>The rack was a new installation (approx 4 years old) designed to use
>R22 and synthetic oil. The compressor are cooled using the copeland
>demand cooling system but there has been multiple compessor failures,
>usually electric suggesting that even with this cooling the discharge
>temps are too high. Being in line with what George Goble said

I assume you mean motor "burnout"? (shorting to ground?)  If so, there is
a huge amount of acid produced and other contaminates from the red hot
windings breaking down ALL the refrigerant they touch, and if the compressor
continued to turn, even for a few seconds, the  acid is pumped through out
the whole system and anything connected to it.

The Best burnout cleanup procedure used to be to "power flush" everything
with R11 to get out all bad oil from the lines, etc, then install
new compressor. Today some  
people use isopentane (same BP as R11, around 77F), but that 
is extremely flammable so precautions must be taken.  Other nonflammable
solvents are starting to emerge now.

There are local technicians who dont believe in proper burnout
cleanup, and they use "new compressors" to clean up previous
burnouts.. The new compressors last 3 or 4 months and burnout
again.. I have seen this go on for 12 or 13 compressors, at which
time they declare the system was poorly designed and replace
the whole system at tens of thousands of $$$.. Good job security.
In the 20 or so compressors I have changed (R11 or isopentane flush),
none has since failed.
--ghg

From: ghg@cidmac.ecn.purdue.edu (George Goble)
Newsgroups: sci.engr.heat-vent-ac
Subject: Re: Flushing agents for refrigeration systems
Message-ID: <4mqc4s$ftr@mozo.cc.purdue.edu>
Date: 8 May 1996 14:46:52 GMT

In article <4movru$dvg@news2.cais.com> cwood@hvac.org writes:
 >jhuber@zeus.anet-dfw.com (Joseph Huber) wrote:
 >
 >>I'm curious as to what the HVAC&R industry is using nowadays for
 >>flushing agents to clean out refrigeration systems.  I'm guessing that
 >>CFC-11 and CFC-113 are no longer used/legal for this purpose.
 >
 >>Thanks!
 >
 >>-- 
 >>Joe Huber
 >>jhuber@anet-dfw.com
 >Joe:
 >Up to now the ozone hot line recommended flushing with nitrogen.  I
 >don't know where you are located but Johnstone Supply, an
 >appliance/hvacr supply house has a "internal coil cleaner" that has
 >replaced 11 for system clean-ups.  The products name is CF-20
 >Johnstone part no.  B81-522.  CFC free, non-flammable, low V.O.C.
 >Leaves no residue, will not contaminate oil or refrigerant, eliminates
 >any acid, etc.   About the same thing the clean-up R11 did.
 >Compatible with mineral, ester, PAG or alkybenzene oils.  
 >Any questions feel free to e-mail me directly.
 >good luck,
 >Charles
 >cwood@hvac.org


R-11 boiled at around 77F and R-113 around 100ish or so..
They evaporated when done.. and systems were easy to pull a vacuum on.
Naptha and other "low volatility" solvents will be hard to remove
with a vacuum, and even worse, they will get into the vacuum pump
oil and not boil out on their own.. This prevents the vacuum pump
from achieving micron vacuums until the oil is changed which prevents
good moisture removal prior to charging.  Anybody know the
formulation of the above solvent?

A bunch of us around here use isopentane, grade "pure".. from
Phillips 66, Borger, TX.. 54 gallon drum for about $450.

It has all the "good" properties of R-11, except that isopentane
is extremely flammable, and precautions must be taken during
service.  I assume no liability or responsibility if you burn/blow up
yourself using isopentane.  Isopentane boils around 77F, so it is easy
to remove from a system.  Use dry nitrogen/CO2 to push it thru, not compressed
air.
--ghg