Refrigerant 404A - Is it Ester Oil Compatible?
robert_w._bass
R134A) for a freezer system as a replacement for R502. I have heard that
R404A is not as compatible with ester oils as other refrigerants. Can anyone
verify or refute this? I would appreciate any information and/or operational
experience using R404A. Thank you
Bob
Techxperts, Inc
Technical and Engineering Specialists
tech...@ix.netcom.com
George Goble
>A client wishes to use Refrigerant 404A (a tri-blend of R125, R143A and
>R134A) for a freezer system as a replacement for R502. I have heard that
>R404A is not as compatible with ester oils as other refrigerants. Can anyone
>verify or refute this? I would appreciate any information and/or operational
>experience using R404A. Thank you
>
The only oils I know of which would work are POEs (esters) or PAGs..
You want to avoid PAGs, since the chlorides (coatings) from the
R-502 will cause the PAGs to break down.
Suggest you call the equipment mfgr and ask them which POE they
reccommend.. POEs have a multitude of possible problems also.
POEs dont foam, and can cause possible compressor lube problems, depending
on the type of the compressor. Wax from winding the motor windings is
insoluable in POEs and may turn to solids, and plug the expansion device.
POEs are very sensitive to moisture andd can break down from this
and sometimes steels (catalyst) back into their consitituant fatty acids and
alcohols. Various mfgrs have secret additive packages to try to
combat these problems. Also, if the compressor needs to be removed
to change the oil, stirring up the sludge/metal flakes in the bottom
as well as extra contamination from brazing comes into play.
There are number of R-502 replacements available.. If it were me, I
would chose one with HCFCs or a small amount of propane (HP80)
and use alkylbenzene (AB) (Zerol brand) oil, as that is just
synthetic mineral oil and will avoid the POE problems.
--ghg
Dennis
>
> Finally, I use 70 pound cylinders. The last 10 pounds have been unusable due
> to seperation of the components. Has anyone experianced this?
Sounds pretty serious, over 14% of your blend is *not* usable? I would
think that you are not getting the right blend in most of your charging
due to what you're leaving behind, therefore affecting the temperature
glide. Do you charge liquid or vapor? Though I have not had first hand
experience with blends, I understand how they work and I had heard back
when they first were introduced that they had to be liquid charged to
maintain the mix going in (which made sense to me). This would of course
require carefully metering the ref. into the suction line while running,
but you didn't hear me say that.
-Dennis-
asc...@mo.net
> POE is required. I use Mobil Artic 22. I compensate for the water affinity
>by vacumning for 24 hours with a Binford 9000 (ok it's an Actel 27 cfm). My company
>is a manufacturer of test chambers using HP62 and R23. 404A is the experimental
>designation. DuPont has given it a proper name.
Jim, R-404A is the ASHRAE designation. SUVA HP62 is the DuPont brand name for R-404A.
There is a new type, SUVA 95
>that may be better than HP62.
SUVA 95 (ASHRAE designation: R-508B) is completely different than HP62. SUVA 95 is an
R-23/R-116 near azeotrope blend which is being used as a replacement for
R-13, R-503, and R-23. As such, it is used in the low stage of a cascade system,
not the high stage where HP62 would be used.
> Finally, I use 70 pound cylinders. The last 10 pounds have been unusable due
>to seperation of the components. Has anyone experianced this?
You should liquid charge 400-series refrigerants into systems to prevent fractionation
of the refrigerant. Losing 10 pounds out of 70 seems excessive, especially at HFC
refrigerant prices. :-)
Andy Schoen
asc...@mo.net
n7...@primenet.com
95 is a R23 substitute.
I use 70 cylinders because of the ease of storage. Each machine is charged
with 1 lb. 6 oz. of R404A. This is difficult to accurately measure from the large cylinder,
so I fill a 20 lb. bottle (DOT approved NOT an old disposable!). I handle the material
only as a liquid.
I have been using 404 for 18 monthes now, 4 70 lb. cylinders. Units charged
with the last 10-15 pounds have run poorly. A check of the cylinder shows the
temp/press relationship is false, that is the cylinder does not match the chart. My
instruments are not lab grade, but better than service grade.
I have tried to very closely track the amount of 404 I remove from the cylinder.
The data for the last one was skewed when the static charge generated by the
flowing liquid reset my digital scale. I now have ESD protection on the scale.
Today I start a new cylinder and hope to have useable data over the 3-6
monthes I will draw from this bottle.
Should anyone be interested, I have an Excel 4 spreadsheet of temp, press
amps etc for our chambers. These are simple cascade chambers with 404 & R23.
E-mail me for details, I'll be posting them to my ftp directory this weekend.
Jim Sullivan
R80
>Subject: Re: Refrigerant 404A - Is it Ester Oil Compatible?
>From: asc...@mo.net
>Date: 12 Mar 1996 04:16:55 GMT
[snip]
Gentlemen:
Just a thought. I have used the blends also but have noticed
one item of interest. On the side of the containers that the refrigerant
comes in there is a notice that the tanks should not be inverted for
liquid charging. I caught myself doing this once. Could this seperation
and loss of the last 10 pounds be from inverting the tank and only drawing
out vapor?
Just a thought.
n7...@primenet.com
valve. Inverting is not needed.
On the other hand... I use liquid CO2 tanks frequently, the dip tube doesn't
extend to the bottom to avoid sucking up the debris. Also the dip tube is sometimes
significantly short, drawing gas when the tank is still 1/3 full. Perhaps the same
thing is happening with the large cylinders?
Jim Sullivan