[Gmecm] OT - alternative refrigerant test... HFC152A

Wed May 15 13:47:54 UTC 2013

Hi Jay.

There are commercial coil-flushing solvents which you use with a "flush 
gun." This is a compressed air powered tool that you fill with solvent, then 
charge it with air, then blow it throuh the coil.

The main thing to do, is to use a highly volatile solvent that doesn't leave 
ANY residue. In other words, which evaporates completely. Things with 
lubricant or protecting film additives would be bad.

I've seen some very dubious flushes sold at auto parts stores. The flushing 
process can bring up the flammability argument, because many of the poor 
performing flushing compounds are touted as 'nonflammable.' One of these was 
basically a 32 ounce can of Ester refrigerant oil.

I use brake parts cleaner as a flush solvent. It is simple and effective, 
however you must take all the flammability precautions. It is HIGHLY 
flammable. I disconnect the car's battery and do the flush outside, away 
from any ignition source. Once the air has blown out the majority of the 
solvent, any remaining residue will evaporate and remove by the vacuum pump.

I wrap the brake cleaner spray straw with electrical tape until it is "built 
up" large enough to seal into the eaporator or condenser fitting. Connect a 
length pf hose (such as 3/4 inch heater hose to the other fitting of the 
coil being flushed. Route this to a safe disposal container. Then spray half 
the can into the coil. Follow with compressed air, to blow out the solvent 
(mixed with the old oil). Repeat with the second half of the can of cleaner.

Three cans per car, one for the evaporator, one for the condenser; and one 
for cleaning fittins etc.

You will see all sorts of brown gunk come out. It's quite a mess.

If your condenser has a bunch of bent fins and crushed areas, you would 
probably be wise to take it off the truck and careully asess it. The bent 
fins can be combed out, and the packed fins can be pressure-washed 
(carefully) to remove the debris. But depending on cost, it might be cheaper 
to buy a new one.

What I've been hit with, is the new ones are Chinese crap and the fittings 
and mounting holes don't always line up. :( So I tend to repair what I've 
got.

Since you say your compressor has "stopped compressing" I would fear it has 
disintegrated internally. You may need to bite the bullet and buy a new 
condenser coil. Those R4 units tend to shoot large pieces of teflon and 
shavings into the system when they fail. The condenser has 2 paths of flow. 
The flush takes the path of least resistance. So, if the compressor shoots 
trash into the coil, and one path is blocked, you can flush the OTHER path, 
and leave half the coil full of shavings. They then slowly work loose and 
wreck your new compressor.

As a general rule, for my own peace of mind, if the compressor had a 
catasatrophic failure I change the condenser coil. I've had good luck with 
junkyard ondensers. Inspect the donor car's orifice tube. If it's not 
plugged, check the compressor. Unhook the lines and turn it by hand and. If 
it pumps air and is not loose and worn, the condenser is probably fine.

Sincerely,
David

----- Original Message ----- 
From: "Jay Vessels" <jay at vessels-clan.com>
To: <gmecm at diy-efi.org>
Sent: Monday, May 13, 2013 10:51 AM
Subject: Re: [Gmecm] OT - alternative refrigerant test... HFC152A

> Hi there!
>
> What is the preferred home method for flushing the condenser and 
> evaporator?
>
> Dad and I have done several R12->R134a conversions.  We change the
> orifice tube, receiver/dryer, and all the O-rings.  If the compressor is
> good, it stays, as well as the evaporator and condenser.  That said,
> there's a reason the R12 leaked out, so that needs to be addressed
> (unless it was the R4 compressor that blew up, which is a different
> discussion).
>
> David's HFC152a conversion has piqued my interest.
>
> My truck's 31 years old this month, and has all of its original hardware
> on it.  It's still holding R12, but the compressor has stopped
> compressing.  I'm replacing everything but the lines, evaporator, and
> condenser.
>
> Dad's trying to get me to replace the condenser, too.  His argument is
> that it's been at the front of the truck, eating everything the road can
> throw at it for 31 years, and a new one not mashed full of debris that
> may not all come out even with a thorough cleaning would likely perform
> better.
>
> Jay Vessels
> 1982 Chevrolet S-10 Sport, 2.8V6 TBI
> 2006 Pontiac Solstice
> 2007 Subaru Outback L.L. Bean, 3.0R
>
>
> On 05/13/2013 11:36 AM, Aaron wrote:
>> I have had good luck with just dropping in R134a in to late 70's GMC Evap 
>> /
>> Thermal expansion valve systems.
>> Typically all the o-rings get replaced, but only because they are SO OLD.
>>
>> -----Original Message-----
>> From: gmecm-bounces at diy-efi.org [mailto:gmecm-bounces at diy-efi.org] On 
>> Behalf
>> Of Gary Evans
>> Sent: Monday, May 13, 2013 11:15 AM
>> To: gmecm at diy-efi.org
>> Subject: Re: [Gmecm] OT - alternative refrigerant test... HFC152A
>>
>> Not easily done from a chemical standpoint I suppose. It's not for lack 
>> of
>> trying there is (or perhaps, was) billions of dollars to be made with an
>> easy replacement.
>>
>> I have had very good luck with drop-is R-134a replacement on mid 80's
>> Japanese vehicles. Dryer and oil change only - kept all the old hoses. It
>> typically goes about 5 years between needing top-offs.
>>
>> -Gary
>>
>>
>>
>>
>>
>>
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