AC Help

[Pasha Saleh]

Posted earlier about issues with the Vintage Air Mini Gen II system in my RCR40 and still not sorted but perhaps a few more clues.

The system was not holding vacuum and I traced it to one missing(!) and another crushed o-ring. Having replaced those, we pulled vacuum and it held for over 24 hours. After charging with a professional refrigerant recovery machine at a repair shop, it ran great for the drive home then the compressor wouldn't kick on the next day. Pressure had leaked to nearly zero overnight. Checked over every fitting and used an inexpensive sniffer tool (lots of false alarms), couldn't find anything, so charged it again and ran the system while hooked up to the recovery machine to read the gauges. High side pressure: 225, Low side: 28 at 1500 rpm. Same thing again. Ran great going home, next day zero pressure.

I don't see any signs of oil leaks anywhere and the sniffer is inconsistent -- mostly goes off intermittently in the area of some of the crimps but only some of the time. We tried spraying the connections and Schraeder valves with soapy water immediately after charging the system, and that didn't show anything either. At my wits end knowing what to do next. Any experience and suggestions would be greatly appreciated!

 

[Michael]

You may want try pressurizing the system with nitrogen and spraying all connections with soapy water to locate the leak(s).

 

[Chris Kouba]

Haven't used them before but fluorescent dye can be added to the system and then illuminated with a UV flashlight:

https://www.amazon.com/ac-dye-kit/s?k=ac+dye+kit

If you have a leak (and it sounds like you do!), this should show it.

 

[Pasha Saleh]

You may want try pressurizing the system with nitrogen and spraying all connections with soapy water to locate the leak(s).

Thx! Where can I buy a bottle of pressurized nitrogen?

 

[Michael]

Welding supply shops will have it, but you may have to pay a hefty core charge for the bottle, and you’ll also need a regulator. Do you have any friends with welding equipment?

 

[Pasha Saleh]

Welding supply shops will have it, but you may have to pay a hefty core charge for the bottle, and you’ll also need a regulator. Do you have any friends with welding equipment?

No unfortunately. Can I just use shop air then replace the dryer (again)? If so, how many psi should I pump in and on both the high and low side separately?

 

[Michael]

Once you locate the leak, you’ll have to open the system to ambient air, so you should change the dryer regardless. Shop air will work, but usually not recommended. Nitrogen can be added at higher pressure than typical residential air compressors can provide. If your home compressor can provide 150 psi, that should work, but once you’ve found and repaired the leak(s), you’ll need to pull vacuum for a much longer period of time to boil moisture out of the system. You can pressurize through low or high side, it will equalize.

 

[Bill Kearley]

Hate to say but go back to your shop explain the problem. They should have added dye at the second try. ,evacuate, have a close look, charge again and add dye.

 

[Chris Kouba]

Did you see Randy's post on your other thread?

Vintage Air Mini Gen II - A/C Not Functioning

If you open your system, you'll need to buy and install a new drier/accumulator.

www.gt40s.com

 

[Pasha Saleh]

About the Schraeder valve caps? It seems like the valves are too deep down in the stem for that to be a possibility. I couldn't get that lucky but will go look at it...

 

[Leonard L]

• AC Pre-Check-System should put under vacuum for minimum of one hour be manually then pressurized (**Sander Method Here**) using 25lbs of dry shop comprossor air prior to initial Charge or Recharge of A/C system. System should have ZERO variance prior to a full freon recharge.
• Once no leaks found, then Vacuum-Minimum 45 Minutes
• Static Pressures- Will very, and generally static pressure will be close to ambient temp
• Operating Pressures- 125-175 high side and 20-30 low side
• Freon- 32 oz of 134
• PAG Oil- 6 oz of PAG if new system and 4 oz on a rewchage due to some residual already staing within system. (A/C System with Ford GT500 AC Pump)
• Once charged cold air at vent will be 41-44 degrees at recirculation setting with highest fan setting and temp control set to lowest setting.
• Operational Notes:
• Leak Advisory: At pressure hose fittings at the end runs through the center tunnel and AC evaporator box it may be necessary to double up O-rings to remedy manufacturer variance in hose end tapers. A variance of .5 MM in flair can create almost undetectable and very slow leaks. Also, some O-rings may have not been well seated and irregular compression may have occurred. Also compression hose end fittings are a commaon place for very slow and hard to identify leaks.
• High RPM and WOT advisory: Due to A/C control not being interfaced within modular ECU, the AC should be turned off prior to extended WOT and sustained high RPM running above 5K. In late model vehicles the AC Pump is disengaged through the ECU at WOT and High RPM as pump balancing is a variable in manufacturing and will result in pump seal failure and worse case seizing the AC pump unit.

 

[Ralph Pas]

Posted earlier about issues with the Vintage Air Mini Gen II system in my RCR40 and still not sorted but perhaps a few more clues.

The system was not holding vacuum and I traced it to one missing(!) and another crushed o-ring. Having replaced those, we pulled vacuum and it held for over 24 hours. After charging with a professional refrigerant recovery machine at a repair shop, it ran great for the drive home then the compressor wouldn't kick on the next day. Pressure had leaked to nearly zero overnight. Checked over every fitting and used an inexpensive sniffer tool (lots of false alarms), couldn't find anything, so charged it again and ran the system while hooked up to the recovery machine to read the gauges. High side pressure: 225, Low side: 28 at 1500 rpm. Same thing again. Ran great going home, next day zero pressure.

I don't see any signs of oil leaks anywhere and the sniffer is inconsistent -- mostly goes off intermittently in the area of some of the crimps but only some of the time. We tried spraying the connections and Schraeder valves with soapy water immediately after charging the system, and that didn't show anything either. At my wits end knowing what to do next. Any experience and suggestions would be greatly appreciated!

Did you leak check with your guages hooked up?
Most times the leak source is from the schrader valve....
FYI...contact your local Refrigeration supply house for Dry Nitrogen...

 

[Leonard L]

I would be happy to walk you through the steps and discoveries I made to finnaly remedy what seems to be the exact same conditions you are experiencing. I am on the West Coast to PST time zone. You can text me at 206-730-0086 to set up a time for a call. Happy to help you out with this as having the AC finally working properly and cold is such a wonderfully thing...you"ll get there.