Enviro-Safe r12a users, Q's on moisture.. - PeachParts Mercedes-Benz Forum

DeliveryValve · #1 04-30-2015, 07:54 PM

One of my low side metal lines unfortunately suffered from a hairline crack. I subsequently removed the line and took a few days to finally braze the crack. I had the exposed line ends taped up while I was doing this.

The previous refrigerant was R12 and now i need to recharge the car. I may still use R12, since I still have a good supply of it, but Enviro-Safe Industrial r12a has my curiosity.

What I read about ES is that moisture is not an issue with it and should be charged with no vacuum pulled (although ES industrial you can).

So my question is if moisture is not an issue, can I reuse the Drier?
It seems to me a waste if you have a new drier and then you expose it to the atmosphere to have the same pressure. Or am I missing something?

.

JamesDean · #2 04-30-2015, 08:01 PM

I think the general recommendation when opening the a/c system is to replace the dryer...but I am lazy and in every ES-12A charge operation I've done I've never replaced it in using the "regular" or "industrial" version. I'm not quite sure what the difference is...if you look at the industrial can it just has a different label. Literally the industrial label is taped over another one.

I normally vacuum down for a while and then turn off the pump. I let it sit for a while to see if it maintains the vacuum then I go ahead and recharge it with the industrial variant.

tjts1 · #3 04-30-2015, 08:04 PM

Never replaced the dryer, never had a problem. If you're pulling a deep vacuum you are by definition boiling off any residual moisture.

DeliveryValve · #4 04-30-2015, 08:07 PM

Thanks for your responses, couple of questions.. Was your lines exposed a bit? Or did you just did a evacuate and recharge? Just trying to determine how much exposure your drier had. So I take it your system is cooling great.

tjts1 · #5 04-30-2015, 08:51 PM

On one car I replaced the hoses and all the O rings, on the other I replaced the AC compressor. In both cases the system was open for several days.

Graham · #6 04-30-2015, 10:25 PM

If dryer doesn't cost that much, maybe just as well to replace it? And vacuum is needed to check for leaks before charging, so any other moisture should be mostly gone. I would do both and not have to worry about any moisture that might have got in while open.

renaissanceman · #7 04-30-2015, 10:55 PM

If you're in central CA, I doubt much moisture got in there (I'm from Fresno, pleasantly dry most of the year). Pull a vac to boil off most of the water, and charge into a vacuum.

I talked to the EnviroSafe "engineer" and he gave me 10 minutes of platitudes as to why not to charge into a vacuum, most of which was dead wrong according to refrigeration theory. I'm finishing my MS in mechanical engineering this spring, and I was not at all impressed with his explanation. He said that the reason you couldn't charge it a vacuum is because they pulled a vacuum on the cans before filling, and you "don't need to pull a double vacuum"

WTF?

Anyway, so I hung up and then proceeded to pull a hard vac and charged by equivalent weight. It's dead cold at speed (I'm still working out the aux fan operation, so it gets warm at a stop).

Calling EnviroSafe robbed me of a little bit of what is left of my (fleeting) belief that humanity is not totally hosed.

vstech · #8 04-30-2015, 10:57 PM

Acck when will everybody listen...

Vacuum is not a valid method of checking an ac system for leaks... Ya HAVE TO USE PRESSURE.

renaissanceman · #9 04-30-2015, 11:14 PM

Quote:

Originally Posted by vstech

Acck when will everybody listen...

Vacuum is not a valid method of checking an ac system for leaks... Ya HAVE TO USE PRESSURE.

I'm with you, it's a good way to remove water/stray gasses, though! Hence my use of EnviroSafe with Dye to check for leaks in my system -- if it leaks out, no biggie, and I can find the source!

vstech · #10 05-01-2015, 12:44 AM

Quote:

Originally Posted by renaissanceman

I'm with you, it's a good way to remove water/stray gasses, though! Hence my use of EnviroSafe with Dye to check for leaks in my system -- if it leaks out, no biggie, and I can find the source!

Only AFTER you have verified leak free... Vacuum introduces moisture if the system is leaky...

Oh, and vacuum in a semihermetic system doesn't get low enough to remove moisture. Have to pull below 1100 microns to be moisture free. A semihermetic system rarely dips below 2000 microns... Flushing out with nitrogen or CO2 or another dry gas is better. Followed up with a new dryer...

tjts1 · #11 05-01-2015, 01:27 AM

Overkill imho.

Vac to 29 inch, fill to desired pressure with whatever HC refrigerant you like then vacuum again. 2 vac and refill cycles will get rid of whatever residual moisture/air/whatever you had in thereto begin with. HC refrigerants are far less sensitive to contaminants that r12 of r134a. The more important bit is to make sure you keep oil in the system.

Graham · #12 05-01-2015, 09:53 AM

Quote:

Originally Posted by vstech

Acck when will everybody listen...

Vacuum is not a valid method of checking an ac system for leaks... Ya HAVE TO USE PRESSURE.

If system won't hold a vacuum, wouldn't that indicate that it might have a leak?

renaissanceman · #13 05-01-2015, 11:20 AM

Yes, it would. Vacuum can indicate when you have a large leak.

vstech · #14 05-01-2015, 11:20 AM

Quote:

Originally Posted by Graham

If system won't hold a vacuum, wouldn't that indicate that it might have a leak?

sure... it will also contaminate the system with water/air... and if it holds vacuum, it does NOT mean you don't have a leak... the seals are designed to hold PRESSURE... testing them under vacuum does NOT test if they are tight...

also, a FULL 29.999999 whatever perfect vacuum cannot be achieved in a semihermetic system due to seals, and hoses and bearings and such. and even if PERFECT vacuum could be achieved, it's only 14.7psi of pressure pushing on the seals... not much to a system designed to handle 300psi operating pressure... I'm just sayin...

JamesDean · #15 05-01-2015, 12:18 PM

Quote:

Originally Posted by vstech

sure... it will also contaminate the system with water/air... and if it holds vacuum, it does NOT mean you don't have a leak... the seals are designed to hold PRESSURE... testing them under vacuum does NOT test if they are tight...

also, a FULL 29.999999 whatever perfect vacuum cannot be achieved in a semihermetic system due to seals, and hoses and bearings and such. and even if PERFECT vacuum could be achieved, it's only 14.7psi of pressure pushing on the seals... not much to a system designed to handle 300psi operating pressure... I'm just sayin...

I agree, pressure is the proper way and how it should be done. I am just lazy and never had the opportunity to gather the stuff. I never get home while places are still open and most are closed on the weekend.

I think nitrogen (right?) is typically used.