I had to replace the condenser on my DD, the 05 Impala. Part of the process of recharging the system said to pull a vacuum. Well, this was a shadetree repair, with me only filling it up with the cans of R134a. The outlet temp gets down to around 60*F, sometimes to 70*. It doesn't stay there at 70* long. The outside temp today was mid to upper 80's, hot and humid. I used a refill can with a gauge, not perfect I know, but it is in the mid range for that. It doesn't seem to have lost any refrigerant in the 3 weeks since the repair. So, does it matter that I didn't pull the vacuum before filling? Would it make sense to take it somewhere to have it recharged by pro's? Thanks. I'm ok with the repair, just wondering if it could be better.
auto a/c
- Thread starter Louie70Dart
- Start date
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67Dart273
Well-Known Member
You CAN cheat to some extent, but you have to be "on your feet." This was "way easier" back in the day when refrigerant was a couple bucks a can, LOL
1...You need proper equipment, IE guage manifold with proper fittings adapters.
2...Assuming a "dead start" with newly assembled system, start with gauge manifold hooked up, valves closed, and 1 can of refrigerant.. Following will depend on "where" the low side fitting is. If it's very close to compressor, leave that port "open" out the low side hose, IE low side hose hooked to system port, and gauge end of hose disconnected.
If port is "away" from compressor inlet, instead, leave the compressor low side hose disconnected
Now hook refrigerant can to gauge manifold, open high side valve, and refrigerant valve. this will inject refrigerant on high side, "sweep" through the system, and eject out the open end of the low side hose.
Whether dealing with open end of gauge hose, or open end of compressor hose, as pressure bleeds off to a low positive pressure, hook hose back up to gauges or compressor.
Now you have some refrigerant in the system, and have 'swept' a lot of impurities, air, and moisture out.
3....Now devise a method (buy fittings) to hook your gauge manifold center hose to intake vacuum. Standard gauges are 1/4" SAE flare fittings. Run engine at idle, for about 1/2 hour. Run heater which will warm up the evap and system in general. This is only going to evacuate system to "about" 18" Hg, but far better than nothing
4....Now you have the system in a somewhat vacuum. "Sweep" another can of refrigerant through system, this time open the high side valve again, with LOW side hose hooked to gauges, and low side valve CLOSED. Watch the low side gauge. When pressure "comes up" out of a vacuum into "positive" pressure, unhook the low side gauge hose, so that the charge can sweep through and out
5.....Repeat vacuum, as above, then, finally, recharge system with proper weight of refrigerant.
NOTE The above is HIGHLY ILL--EAGLE and violates every single Federal U.S. Law ever passed!!!!! You may be going to jail for a very long time!!!!
Also NOTE that I did not address system oil charge!!!! Make sure this is properly addressed.
NOTE!!! I would NEVER do this. NEVER. nope. Well, mostly, not.......
1...You need proper equipment, IE guage manifold with proper fittings adapters.
2...Assuming a "dead start" with newly assembled system, start with gauge manifold hooked up, valves closed, and 1 can of refrigerant.. Following will depend on "where" the low side fitting is. If it's very close to compressor, leave that port "open" out the low side hose, IE low side hose hooked to system port, and gauge end of hose disconnected.
If port is "away" from compressor inlet, instead, leave the compressor low side hose disconnected
Now hook refrigerant can to gauge manifold, open high side valve, and refrigerant valve. this will inject refrigerant on high side, "sweep" through the system, and eject out the open end of the low side hose.
Whether dealing with open end of gauge hose, or open end of compressor hose, as pressure bleeds off to a low positive pressure, hook hose back up to gauges or compressor.
Now you have some refrigerant in the system, and have 'swept' a lot of impurities, air, and moisture out.
3....Now devise a method (buy fittings) to hook your gauge manifold center hose to intake vacuum. Standard gauges are 1/4" SAE flare fittings. Run engine at idle, for about 1/2 hour. Run heater which will warm up the evap and system in general. This is only going to evacuate system to "about" 18" Hg, but far better than nothing
4....Now you have the system in a somewhat vacuum. "Sweep" another can of refrigerant through system, this time open the high side valve again, with LOW side hose hooked to gauges, and low side valve CLOSED. Watch the low side gauge. When pressure "comes up" out of a vacuum into "positive" pressure, unhook the low side gauge hose, so that the charge can sweep through and out
5.....Repeat vacuum, as above, then, finally, recharge system with proper weight of refrigerant.
NOTE The above is HIGHLY ILL--EAGLE and violates every single Federal U.S. Law ever passed!!!!! You may be going to jail for a very long time!!!!
Also NOTE that I did not address system oil charge!!!! Make sure this is properly addressed.
NOTE!!! I would NEVER do this. NEVER. nope. Well, mostly, not.......
..........I'm no expert by any stretch of the imagination but 1 of the biggest problems I see is that not very many ppl add oil to the system, its what carries the refridgerant around the system..........kim.....
67Dart273
Well-Known Member
What a "little too much" oil does: Coats the insides of the evap coil and reduces system capacity
What a "little too little" oil does: Kills / freezes/ junks the compressor, in one easy lesson
This deals with electric (hermetic) compressors but the ideas are the same.............
no oil, not enough, or loss of due to leak(s).........
flooded start (liquid refrigerant collecting in compressor shell)
flood back (over charge)
slugging (extreme over charge)
overheating (various causes including UNDER charged)
[ame="https://www.youtube.com/watch?v=67LjLLjsRTM"]COMPRESSOR OIL LOSS 101 - YouTube[/ame]
Thanks people. Late at night, time to go to sleep. I'll reread this tomorrow when it isn't so darn hot and humid. I know that we need a recovery system to properly work on the A/C these days. Gotta save that ozone layer!! I'm leaning towards taking it someplace and having them do it the proper way. It was a big hassle just to change the stinking condenser, but I didn't take the radiator out like it was called for. I was able to remove the one tranny line and upper radiator hose and move the radiator out far enough to pull the condenser out and put in the new one. I consider it a success just because after three weeks it is still working. I don't want to spend money on things I will probably only use once, plus I really don't know what the hell I would be doing, even after the great tips from you guys. I was wanting to know more about the ac and I got the help. Thanks!
rednesss
Well-Known Member
You have to pull a vacuum and evacuate out non-condensable gases (water vapor). Go to Harbor Freight, they have vacuum pumps for under $100
67Dart273
Well-Known Member
Just a little hint.........if it's all leaked out, there's nothing to recover!!!!!
LOL, yeah I didn't give a hoot in the beginning. I just hate to waste money on the damn thing. Like I said, it works ok, I just wonder if it couldn't be better. I mean it drops the temp around 20* from the outside, so I really can't complain. Or can I anyway? LOL
bcschief
Well-Known Member
Go to Autozone and use there loan a tool program they have vacume pumps and manifold gauge sets that you pay for up front and then return them when your done for a full refund.
Brian
Brian
72dust
Well-Known Member
Autozone and others have a vacuum pump for rent. Put deposit down get money back when you return the item.
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