CAV A/C Help

Veek · #1 (**permalink**) 06-02-2013, 05:13 AM

Help! Does anyone have the amount of R134 refrigerant the CAV uses? I’ve replaced the compressor and my A/C tech need the amount of initial R134 fill. In going over some old documents, I saw a reference to 550-600 grams but that seemed a bit on the low side. Might any of you have any information available as to the proper amount?

Thanks!

bmwdb10 · #2 (**permalink**) 06-02-2013, 02:18 PM

Hey Veek,

I am not really sure that there is an actual requirement for refrigerant. Doesn't the system just pull what ever the evacuation vac pulls?

I checked my material from CAV and I dont see any specs. Have you emailed Johann or the SA crew?

98 degrees yesterday here in NH. Buttoned up the vents and pop-outs and turned on the AC. Went for a great ride, very comfy!

Dave

Veek · #3 (**permalink**) 06-02-2013, 04:26 PM

Thanks Dave, I've spoken to Johann and he really didn't have an answer other than let the low side go to 35lbs. I found a 2002 CAV letter referring to 550 grams (1.2 lbs) but that was as the factory was testing the prototype units. I also have an email to Jean in SA. Like you, there isn't anything in the owners material I got with the car.

bmwdb10 · #4 (**permalink**) 06-02-2013, 06:12 PM

Yeah, I would agree with Johann... Once you vac the low side it will take what it takes and that is pretty much it. I think the 550-600 grams is likely to be capacity in the system. I think the amount the system will pull will depend on the vacuum at evacuation.

I'm sure Jean will reply. They were pretty good about getting back to me about the master cyl issue. Although, what they suggested isnt avail here in the States and incorrect to boot.

Dave

Bob Hess · #5 (**permalink**) 06-11-2013, 01:52 PM

Your A/C guy should be able to charge the system with the correct amount of R-134A by checking the suction line temperature, superheat, and air temperature from the evaporator. If you have a sightglass(?) in the liquid line it would be a big help but not necessary. Clear as mud, right?

Veek · #6 (**permalink**) 06-22-2013, 05:46 AM

Thanks Bob, the CAV does have a sight glass and in discussion with the factory, that's how they fill it.

Bob Hess · #7 (**permalink**) 06-22-2013, 08:56 AM

When the sightglass has a continuous, full stream of refrigerant going through it, it will look clear (empty). This should happen about 2k RPM and up with the fan on high speed. If you see bubbles in the sightglass add more. Check the suction line temperature and make sure you have no liquid refrigerant returning to the compressor. Too little refrigerant is not good and too much refrigerant is not good.