Detailed step-by-step on how to top off R134a in air conditioner that is not working - JeepForum.com
 
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post #1 of 5 Old 08-14-2017, 08:59 AM Thread Starter
wakedad
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2002 WJ 
 
Join Date: Mar 2014
Location: Livonia
Posts: 50
Detailed step-by-step on how to top off R134a in air conditioner that is not working

Update Aug 15, 2017. I would appreciate it anyone could provide some input on item numbers 10, 16, 19, 24, and 26. Input on any of the other items is also greatly welcome! Thank you.



The air condition on my 2002 Jeep Grand Cherokee, with 156,000 miles, died a couple of weeks ago. It is getting pretty warm without air so I have decided it is time to eliminate that problem real soon!

The following is a step-by-step procedure to add R134a to air conditioner that is not cooling anymore. I don’t have any plan to do the whole vacuum process since the system was never opened up and exposed to outside air… I think it just had a leak and lost fluid. I know this is not the perfect process that a pro would do, but I am just a simple DIY’r and have done something like the following on multiple vehicles and never had any problems. I just sold a 1998 Jeep Grand Cherokee that had over 225,000 miles and air was cold as could be. I also have a 2007 Dodge Grand Caravan with over 178,000 miles and air on that one is also cold. I did multiple top ups of R134a on both vehicles with no problems.

The R134a that I use is AF-3 | Arctic Freeze® Ultra Synthetic R-134a+
http://www.rechargeac.com/products/o...ar-refrigerant


I would appreciate your comments and suggestions so that I can make any corrections or improvements to the following procedure. Thank you in advance!!!

1. Make sure o-rings are inside of manifold connectors.
2. Turn dials to right to close. (Blue is low pressure, smaller port, sucks in r134a) ( Red is high, larger port, pushes R134a). Also, close Yellow R134a “supply” hose valve.
3. Attach hoses to ports.
4. Take low and high side air pressure readings on manifold gauges.
5. Shake R134a can well.
6. Put fitting on can.
7. Attach yellow hose to can.
8. Pierce can and open valve.
9. Loosen yellow hose fitting at manifold to get rid of air.
10. Loosen blue hose fitting at manifold to get rid of air (is this necessary and correct if you didn’t run vacuum pump?)
11. Get hot pan of water to put R134a can in.
12. Get instant read thermometer.
13. Open all windows and doors.
14. Set A/C button to the on position.
15. Set the temperature control to full cool position.
16. Select Recirculation Mode (not bringing in outside air), (Note… in another section of FSM it states Set to “Fresh Air Mode, instead of Recirculation Mode). Since FSM states two different Modes I would appreciate comments on what you think.
17. Select air coming out of top center vents (not floor).
18. Set blower to highest speed position.
19. Start car and hold engine to 1000 RPM with the compressor clutch engaged (Note… FSM says to use 1300 RPM in a different section of FSM). Also, on “Eric The Car Guy” video he states using 2500 RPM. Since FSM states two different RPMs, and Eric says 2500 RPM, I would appreciate comments on what you think.
20. Allow engine to warm up to normal operating temperature.
21. Open Yellow (supply) manifold valve.
22. Open Blue (low side) manifold valve.
23. While charging rotate can between 12 o’clock and 3 o’clock positions every 2 to 3 seconds while continually shaking can back an forth. Should take 5 to 15 minutes till can feels empty. When can feels empty, hold it upside down for one minute to dispense any remaining R134a from can.
24. Close low side valve to check pressure at any point during charging to check low and high side pressure. (Note… FSM says at 70 degrees and 80% humidity the low side should be 35-40 PSI, and high side should be 180-260 PSI. FSM says at 80 degrees and 80% humidity the low side should be 38-42 PSI, and high side should be 200-280 PSI. FSM says at 90 degrees and 80% humidity the low side should be 39-43 PSI, and high side should be 200-280 PSI.) Does anyone have PSI for 40% and 59% humidity? Also, in a different section of FSM it states that at 80 degrees the high side PSI should not exceed 250 PSI instead of the 280 PSI stated in another section of FSM… what do you think?
25. When you change cans;
___a. Close Yellow hose valve at manifold
___b. Close valve at can
___c. Unscrew can from valve
___d. Screw on new can
___e. Open valve at can
___f. Slowly open valve at manifold
___g. Close low side valve at manifold to check pressure
26. Close low side valve to check pressure at any point during charging to check low and high side pressure (Note... I believe you can only check pressure when the air conditioner clutch is engaged).
27. When you are satisfied that you have charged your system:
___a. Close valve on can
___b. Open up manifold low side valve to suck R234 out of yellow hose.
28. Take low and high side hoses off while car is running.


Last edited by wakedad; 08-15-2017 at 04:21 PM. Reason: Update with additional information.
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post #2 of 5 Old 08-15-2017, 04:33 PM Thread Starter
wakedad
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Join Date: Mar 2014
Location: Livonia
Posts: 50
I would greatly appreciate it if anyone could provide some input on item numbers 10, 16, 19, 24, and 26. Input on any of the other items is also greatly welcome! I am hoping this will not only help me, but also help others in the future who need to have a detailed step-by-step procedure.
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post #3 of 5 Old 08-16-2017, 10:07 PM Thread Starter
wakedad
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Join Date: Mar 2014
Location: Livonia
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Does anyone have a chart that shows what the low and high pressure PSI readings should be for different combinations of temperature and humidity. It would be great if you had it for temperatures like 70,75,80, 85, 90 and humidity of say 55, 60, 65, 70, 75, 80, 85, 90, 95 for each temperature. Even a small subset of the above would be great.
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post #4 of 5 Old 08-16-2017, 11:53 PM
GSRaromatherapy
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I was taught how to charge automotive systems differently than what you're posting. I'll post what I do and why I was told to do it this way. (I work on appliances and utilize my gauges and a 30lb tank of 134a.)

Turning the tank upside down allows liquid to enter the gauges and the system. Upright, the refrigerant tank allows gas to enter the automotive system. I've been told that hitting the system with too much liquid can cause damage to the compressor, so I only charge from the low side adapter and charge by using 134a in gas form.

After attaching the adapter to the car and purging the air from the tank line, (turn on tank and tighten connection while the line is pressurized. I loosely attach my low side hose (blue hose) and purge that line the same way, after opening the low side valve as I tighten up the connector. I run the air conditioner at full blast and on the recirculating setting.

It doesn't really matter if it's fresh air or recirculating, as long as air is flowing through the evaporation coil. I have been told by a few people about the RPM range being up around 2500 to 3000, but was told by the mechanic who showed me how to do the system recharge that as long as the clutch was engaged on the compressor you should be fine. So far I've had no issues leaving it at idol and have recharged about half a dozen cars/trucks.

As for pressures. The clutch on the compressor will not engage under 20 psi. So if it goes below that while running it kicks off. If this happens just add bursts of refrigerant until it is running constantly. From there you want to charge the ac until the suction line under the hood is cold enough to pick up condensation This is usually around 38 to 40 on my low side gauge. Temps around here in eastern Nebraska are around 80 - 90 and high humidity. He told me to charge it this way as it will run the best and if I didn't have a gauge I could still do the charge.

Hope this helps.
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post #5 of 5 Old 08-18-2017, 08:25 AM Thread Starter
wakedad
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Join Date: Mar 2014
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Quote:
Originally Posted by GSRaromatherapy View Post
I have been told by a few people about the RPM range being up around 2500 to 3000, but was told by the mechanic who showed me how to do the system recharge that as long as the clutch was engaged on the compressor you should be fine. So far I've had no issues leaving it at idol and have recharged about half a dozen cars/trucks.

As for pressures. From there you want to charge the ac until the suction line under the hood is cold enough to pick up condensation This is usually around 38 to 40 on my low side gauge. Temps around here in eastern Nebraska are around 80 - 90 and high humidity.

Hope this helps.
Thanks for your input, it is really a big help to see what other Jeep owners have done!

Like you, I have seen different advice on RPMs to run at when charging. I have seen 1000, 1300, and 2500. You have heard 2500-3000, or just leave it at idol. I think I heard that the high side gauge reading are different at the different RPMs. If anyone else has some input on the RPM for reading the gauges or charging it would be really appreciated.

Thanks again GSRaromatherapy for sharing your knowledge and experiance!
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