Say I have an empty AC and am going to fill it with a product that says to have 10 inches of vacuum.

Short of taking it to a shop or buying an AC vacuum for a couple of hundred dollars, how can you pull a vacuum on it?

 

theoretically.... and to an extent, mechanically, possible to use the existing a/c compressor to pull it into a vacuum.... but that's a big subject and could destroy the compressor. And it would really only do <U>most</U> of the system in a vacuum.

Without putting a vacuum pump on it... the only other way would be to open the system, drive the car into a room, put the whole room in a vacuum while in there with an astronaut suit on, and reseal the system... not happening.

And... more importantly. If the system is not currently in a vacuum; there is/was a leak... and therefore is currently moisture and other contaminants (air and freon and oil= phosgene gas == mustard gas == acid == bad). So really... it's going to have to first be flushed (r11 is a good flusher and fairly cheap, but not legal) (the legal ones don't work very well) reoiled, recharged, etc; in order to do it correctly and relliably.

and it is actually illegal to purchase freon (in any amount) without a license. and yeah, walmart and autozone and everybody else is breaking the law... and so are you... but that's just my disclaimer.

edit: my statement about "if not currently in a vacuum" is somewhat false... should be if not currently in a vacuum, or positively charged with freon.... just so i don't get flamed for misinformation. also... it is also possible to put it in a vacuum by using temperature/pressure relationships to put in vacuum. ie: fill the system with air, increase temperature of system dramatically, and reduce ambient temperature dramatically... then pressure/temperature differential would suck the air out of system when opened..... but that's no fun, tedious, dangerous, unwise... you get the point.
eidt2: just wanted to add that you could also hook up a canister of say twice the volume of the system that is in 20" vacuum to the system and when they even out their relative pressures both would have about 10" vacuum in them... disconnect and there ya go... but where ya gonna find such cylinder?


Modified by civic_dork at 8:34 PM 4/15/2006

 

I'm bored, and found it interesting:

http://www.dream-models.com/eco/vacuumpump.html
http://www.berkut13.com/sucker.htm

...yes i know i'm weird...

 

umm I didn't really get what the guy above me said but whatever it is it seems preety confusing and probably won't work...what you need to do is bring your car to a shop and let them do it, they have A/C machines that can suck everything out of the system creating a vaccum inside, in the same sense you should probably let them recharge it too since it would be a lot less crap for you to mess with and they will have to vaccum everything out anyways before recharging it assuming the system is empty (they'll probably not charge you any labor to put the freon back in and just charge you for the freon)...did that make sense?

btw if your system is not completely empty you might not need to have a vaccum in it before recharging, also what these A/C machines are are basically compressors that vaccums everything out of the A/C system.

 

Okay, I'll fess up. I converted to R134a. Paid someone to do it. I am not satisfied with the performance. I want to try Dracool, a propane product, that is not legal in the states but is legal in Canada. Yes, we could argue about whether it is saf or not. But I want to give it a go. Every shop I call says "You just want to evacuate it?" and are suspicious. They also want to charge $50-65 to do it.

Now the Duracool says you can flush it with their product. But I am trying to be environmentally correct here. At $50 though, I am losing patience. I may just bleed it out, change the drier, flush it, and install Duracool.

 

Charles, I feel sorry for you. It's going to be a blistering summer here in the Lone Star state.

I just spent $900 getting my a/c system nearly completely replaced, and done right with R12. It's perhaps my best investment yet for my 4dr.

Have you thought about using Freeze 12?

If you just want a vacuum on the system to rid everything of it nearly any service shop should do it for you for free. It's virtually no labor for them, and it's not like they'd be losing any money. Pep Boys did it for me for free.

 

i bought a retrofit kit from napa, $30, changed NOTHING else, pumped 134A in it $10 and it blows colder than a witches tit. didnt use a vaccum or anything. something is wrong with your system. it could be your heater valve

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by gold EF &raquo;</TD></TR><TR><TD CLASS="quote">i bought a retrofit kit from napa, $30, changed NOTHING else, pumped 134A in it $10 and it blows colder than a witches tit. didnt use a vaccum or anything. something is wrong with your system. it could be your heater valve</TD></TR></TABLE>

You did it wrong then. You really should get all the R12 out before you pump the R134 in.

And R134 retrokits are not good performers in the long run.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Jonathan_ED3 &raquo;</TD></TR><TR><TD CLASS="quote">Have you thought about using Freeze 12?

If you just want a vacuum on the system to rid everything of it nearly any service shop should do it for you for free. It's virtually no labor for them, and it's not like they'd be losing any money. Pep Boys did it for me for free. </TD></TR></TABLE>
I'll check with them. I really want to try this Duracool as it is getting great reviews and makes sense from a physics POV. If it doesn't work, I will probably go with Freeze 12.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Jonathan_ED3 &raquo;</TD></TR><TR><TD CLASS="quote">You did it wrong then. You really should get all the R12 out before you pump the R134 in.

And R134 retrokits are not good performers in the long run. </TD></TR></TABLE>

yes, i took the r12 out first, duh.

ive had it for 4 years, it blows cold still

 

What do you mean duh? You JUST said in your last reply that you didn't change anything or use any vacuum before installing the R134 conversion.

So how did you get the R12 out?

 

He probably killed some penguins and cracked open the system.. heh

 

It will 'work' without evacuating it first. But then you're taking a big risk of it getting acidic and eating up from inside out. Not only that, but air is non condensible, and moisture is noncompressible.... and the a/c system has a condensor and a compressor, you figure it out. (BANG) (the safety plug/valve that will blow costs 35 bucks)

The 134A kits aren't so bad... you're really suppose to change the drier, fully flush the system to do it... but hardly anyone does. It sure beats paying $$$$$ for r12 (liquid gold). It also won't work as well without evacuating... since air is a **** poor refrigerant.

And it's actually more essential to get all the old oil out, than it is to get the r12 out. The oil is what really traps moisture, contaminants, and all the other nasty stuff. But again, few people ever do.

50 - 60 bucks really isn't sooo bad... heck the shop i work at would charge triple that just for you calling. (not an automotive shop obviously)

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Jonathan_ED3 &raquo;</TD></TR><TR><TD CLASS="quote">What do you mean duh? You JUST said in your last reply that you didn't change anything or use any vacuum before installing the R134 conversion.

So how did you get the R12 out?</TD></TR></TABLE>

calm down, dont get your panties all up in a bunch. im ase certified in AC. i evac'd the system like this guy said:

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Cuda70 &raquo;</TD></TR><TR><TD CLASS="quote">He probably killed some penguins and cracked open the system.. heh</TD></TR></TABLE>

then i filled it with the retrofit, then i filled it with 134a while hooked up to my manifold kit and checked the pressures both on the high and low side.

i just wanted to see if it would work without doing any of that fancy **** everyone says to do. and it works, and has been working for 4 years mmk?