Industrial ES12A= 40 degrees F - PeachParts Mercedes-Benz Forum

airedale2 · #1 08-20-2008, 05:53 PM

Vacuumed my ac system on my 300d today. The r134 was putting such a strain on my engine, my mpg were suffering. So i replaced the r134 with the propane mixture, and i have 40 degrees at the vent. I need to play with it some more, i may have it a little overcharged, but i will wait till it hits 100 again to make final adjustment. No more strain on the compressor or engine like before. Please spare me the fire hazard excuse. Im a fireman in dallas and have seen lots of car fires/houses. Never once saw a problem with pressurized gases. Just gasoline. I start ac school this semester and plan to make propane conversions my specialty. Probably have to go to europe/canada for hydrocarbon specialization classes/cert.

Matt L · #2 08-20-2008, 06:06 PM

Did you evacuate the system completely before installing the refrigerant? Air in the system will cause the high side pressure to rise without giving additional cooling.

I'm not sure about ES12A, but with 134a, if you get optimal vent temperatures you are probably just a bit short on refrigerant. However, I'm not sure that I'd call 40F optimal.

airedale2 · #3 08-20-2008, 06:17 PM

Vacuumed for 45minutes. Held 29mmhg for 1 hr with no change. Now i need to source a more powerful alternator to get my fan blowing harder. For 24 yr old car, i'll take 40 good. Need to order some ES12A so i can play with the system to see just what this gas is capable of.

airedale2 · #4 08-20-2008, 06:19 PM

Please excuse the grammar errors. Sometimes my brain outruns the fingers.

79Mercy · #5 08-20-2008, 06:19 PM

I also used the ES12a. The R134 was causing the old york to compressor to knock and pull alot of HP from the motor. With the ES12a I can even tell the compressor is on. At idle the air gets alittle warmer, but while moving it gets pretty cold.

airedale2 · #6 08-20-2008, 06:26 PM

Mine warmed up a little at idle also. My lo pressure was around 20 and high was around 150. I have an R4 compressor, it became silent after changing refrigerants. I am out of ES12A at the moment, otherwise i would like to take the pressures up a bit to see if i can bring the idle temp down. Just not sure how low that would take running temps down to. Either way, i need more gas before i make adjustments. Noticed any mileage changes with propane?

Matt L · #7 08-20-2008, 06:34 PM

Even without the pressure-temperature chart for ES12A, 150 PSI sounds too low.

The important thing to remember about an undercharged system is that the refrigerant must move the oil. Even a slight undercharge causes severely diminished oil return through the evaporator. While mineral oil (or some synthetics) is undoubtedly more miscible with ES12A than PAG is with 134a, that doesn't matter much when the refrigerant is a gas.

airedale2 · #8 08-20-2008, 06:46 PM

150 is low, but charging based on weight per manufacturer specs. Slight overcharges with this gas have a very negative effect on cooling. Either way, i wont be making any adjustments until i get more product. As for the oil, pag or ester dissolve completely in this gas. It is not dragged through the system like r134. As best i can put it, it become a fogging type of oil and promotes superior lubrication regardless of pressure. Thats just the nature and simplicity of the gas. Hard to argue with a silent compressor. It has also been recommended to go with a heavier weight oil because of this effect.

79Mercy · #9 08-20-2008, 06:49 PM

you need to get the low side pressure up to about 35PSI. Actually my mileage did increase by 1 or 2MPG.

airedale2 · #10 08-20-2008, 06:58 PM

Im shooting for 25-28 on the low side, but will keep 35 in mind. Thanks for the input. Will f/u with results when more product comes in. Wish i could source some locally. Want to stay away from the stove top stuff.

Matt L · #11 08-20-2008, 07:02 PM

Quote:

Originally Posted by airedale2

Im shooting for 25-28 on the low side, but will keep 35 in mind. Thanks for the input. Will f/u with results when more product comes in. Wish i could source some locally. Want to stay away from the stove top stuff.

If 134a were not so cheap and easily obtained, I may have attempted to convert my system to HCs. But we all know how well 134a works in old cars. If you change the condenser to a PF style, it helps a lot. But that's a lot harder than just bolting the part into the car.

Look at the pressure-temperature chart. You want the low-side pressure to reflect just above 32F. Otherwise you will be cycling your compressor too much due to a too-cold evaporator.

airedale2 · #12 08-20-2008, 07:04 PM

Im not certified as an ac tech as of yet, but i think those pressures are way to high even for r134. I think those would trigger your high pressure switch. Besides, pressure is pressure whether it be water or gas.

airedale2 · #13 08-20-2008, 07:08 PM

Yes it is labeled. And since no one but me touches my vehicles, i stopped having mechanical problems. From transfer cases to front ends, just my fingers on my car. My wife breaks em, i fix em.

Oracle12345 · #14 08-20-2008, 07:12 PM

400 and 150 is how much vacuum it should be pulling.

25-35 psi is normal for low

150-200 psi is normal for high

airedale2 · #15 08-20-2008, 07:38 PM

Correction, 29inhg for vacuum. Sorry, i was thinking blood pressures.