A/C not taking recharge?

[SVO42]

My 1994 Ex has shown no change in the low side pressure after adding 2 cans of R134a/oil. My neighbor mention a clogged orifice tube? Any advice on how to fix this?

 

[firewolfm]

AC system recharge

First of all was the system opened up?
If it was did you evacuate the system before you attempted to recharge?
There are products that will detect a leak in your AC sys. I would try to run that test first because if you have put in 24 oz. of refrig 134A and there is no pressure change the gas is going somewhere?

 

[manaen]

And to add to FW's post. if the system was completely drained is should be opened and flushed clean all the lines and the orifice. If you checked the pressure right after adding the fluid and there was none, then you must have a major leak which should be able to be seen without a leak detector. To properly diagnose a clog you should check the high side pressure as well and compare the high and low side pressure.

If your compressor is engaging you must have some pressure in the line otherwise the pressure sensor would not allow the clutch to engage the pump.

In any case to properly diagnose the situation we would all need more information.

1) does the pump engage?
2) what is the high side pressure?
3) did you do a pressure test with the system running or idle?
4) did you trace all the lines to check for leaks cracks etc... you should see oil leaking out around the problem areas.
5) did you install a can of leak detector die? that will aid in finding the leak if there is one.
6) when you say no change in your low side pressure, are you reading any pressure at all, or is there nothing in the system.
7) if there is pressure what is the static PSI (system not running) and the running PSI

some of these questions overlap but will help to actually pinpoint the problem area.

 

[SVO42]

I'll admit I did quick & dirty--I just wanted it to work through the weekend and then do a proper job later. Anyway, more info:

compressor does not engage

did not check high pressure side, I assume I'll need a different gauge?

I did not see any obvious leaks

I checked the low pressure port with the engine running, A/C on max, and get readings around zero, before and after adding the two cans

did not evacuate the system

the refrigerant I added did not have leak detector dye

the A/C worked flawlessly last summer


Wow, now I feel even more like a dumbass after typing all this out. I'll be gone over the weekend, but I appreciate any input, guys. Thanks a lot!

 

[gsmaclean]

I'll admit I did quick & dirty--I just wanted it to work through the weekend and then do a proper job later. Anyway, more info:

compressor does not engage

did not check high pressure side, I assume I'll need a different gauge?

I did not see any obvious leaks

I checked the low pressure port with the engine running, A/C on max, and get readings around zero, before and after adding the two cans

did not evacuate the system

the refrigerant I added did not have leak detector dye

the A/C worked flawlessly last summer


Wow, now I feel even more like a dumbass after typing all this out. I'll be gone over the weekend, but I appreciate any input, guys. Thanks a lot!

If it's leaking out that fast, you should be able to hear it. With the engine off, put a can of refrigerant into the low side, and listen for where it is hissing (leaking) out.

 

[manaen]

First, don't feel stupid, you've just learned something, and that separates you from the average dumby, now get back in there and start over. take your time and it is not that bad, if the system was just working last summer your chances are good that you can have a healthy system after fixing the leaks

as GSM said it has to be very obvious where the leak is, and there should be oil all over the area of the leak. I would trace all the lines and especially check the condenser and look for leaks, it is common to get a cinder thrown up in the northeast winter and puncture the condenser, with 0 PSI you will need to flush everything. It sounds like an overwhelming task however give yourself a day and a few cans of air conditioner flush/solvent. clean and flush all the lines and orifice, I use an air compressor to force the cleaner through the lines you will see some horrible looking stuff coming through (mostly old oil). Pressure test the system before installing new r34a by adding some air pressure and let it sit for an hour or so and check for leaks and test the pressure to see if it changed. Now here is the only tricky part, you need to get all the air out of the lines before installing new refrigerant. The best method is a vacuum pump to suck the air out of the lines however in a pinch once(when my vacuum pump broke) I used a spare can of r34a (all certified tech's stop reading here) to somewhat flush the lines and push the air out of the lines. You need to hook up the can to the low side and then open the high side and let the can blow through. In theory it should push all the bad moist air out of the lines, that is really the goal, to ensure there is no moisture in there. (ok techs you can continue here) That is not the recommended method and according to Mr. Gore (cough cough) our world has gotten warmer by 1/2 a degree so my mountain land will soon be beach front (YESSS! my evil plan is working). But I digress

once you have everything pressure tested and flushed you can fill the system with the recommended conditioner, oil, and r34a, do not overfill or you run the risk of frying your pump with high pressures.

once filled run a test to make sure the static pressure and the pumping pressure are good on the low side.

I've done two systems like this and I started out with little to no knowledge of AC systems and read a lot and talked to a lot of people. As usual there were varying opinions but I had positive results both times.

Good luck let us know how it works out for you.

 

[Glacier991]

There are quite a few good threads on here regarding the orifice tube and how to replace it. As suggested you should probably remove it to check and if it is gunked up, replace it and flush the system. Frankly when I find that I also like to replace the little muffler on the return line as it cannot be readily flushed. Overkill? Maybe. Definitely flush the condensor though and if you cannot get it clean replace it. (half the time it needs to just be replaced) Replace the accumulator, at the same time, regardless.

I'd have it professionally recharged if you lack a vacuum pump. No just adding refrigerant into an empty system. As for the blow it out with a can of 134... I am placing fingers in ears and whistling.... and throwing a wink. BUT.... the vacuum will get get enough refrigerant in the system to run it... that method will not.

In the for what it is worth category.... really good shops will purge the system with dry nitrogen and THEN evacuate it... before recharging. Air in this situation is considered non-compressible and robs you of capacity, moisture creates acids leading to black death.