<VV> 66 A/C Update
shortle556 at earthlink.net
Mon Aug 22 15:18:43 EDT 2016
And Garry, guessing on how much refrigerant you are putting in ("I think I added a pound") is by no means a professional way of servicing your A/C system. Just sitting there with a 30 pound cylinder partially empty is nothing more than guessing. Sorry if this is what you don't want to hear. With the system off, both high and low pressures should be close to equal. Never do you want to see the low side pressure (suction side) go hardly any lower than 30 PSI. If your system is fully charged (proper amount of refrigerant) and the low side goes too low that means you have a restriction (expansion valve? Hose? Evaporator core?). 11 PSI with the compressor off tells me the system is almost empty of refrigerant.
BE SURE TO WEAR SAFETY GLASSES WHEN WORKING ON CARS WITH A/C.
Timothy Shortle in Durango Colorado 81301
>From: Garry via VirtualVairs <virtualvairs at corvair.org>
>Sent: Aug 20, 2016 8:36 PM
>To: virtualvairs at corvair.org
>Subject: Re: <VV> 66 A/C Update
>Guess I missed the part about the 11 psi being with compressor off. I
>knew that sounded low, but couldn't reconcile the numbers. I will
>continue the charge tomorrow, and report back.
>On 8/20/2016 9:18 PM, Frank DuVal via VirtualVairs wrote:
>> Bubbles in the sight glass means low charge.
>> 150 still way low for 80 degree at air inlet. Just add more R-12. I
>> would not be concerned until the high side goes over 225. And I still
>> would not be concerned if the system cooled properly.
>> Note, and I quote the 65 manual since that is in my computer, the low
>> pressure reading of 11 or so is when the compressor cycles off, not at
>> steady state running. The evaporator needs to get cold in order for the
>> thermostat to cycle the compressor, at which point the low pressure side
>> will be low because the evaporator is at a low temperature. With a low
>> charge, the thermostat will never cycle the compressor off.
>> Around here I do not recall ever seeing low pressure below 20 psi on a
>> typical day, 30 would not be bad if the system was cooling OK. Those low
>> readings might be car in the shade (i.e. laboratory or shop). A non
>> Corvair (cycling clutch system) would ice up if the low side pressure
>> was only 12 psi! If you look at your gauge, or an R-12
>> pressure-temperature chart, you will see a low side pressure of 10 psi
>> is zero degrees F! That's a freezer, not an A/C.
>> Frank DuVal
>> On 8/20/2016 6:09 PM, Garry via VirtualVairs wrote:
>>> Hi all,
>>> Here's what I did and found today on the 66 Monza A/C.
>>> Ambient temp: 80 degrees
>>> Static pressure: 84 psi
>>> Added seals to condenser, taped up all holes (not many), and ran hoses
>>> thru back-up light and sealed off. Engine running approx 2000 rpm, low
>>> side pressure was 10 psi, high was 130 psi, output temp 80 degrees,
>>> with bubbles in sight glass. Added small amount of R-12, maybe 1/2-1
>>> pound, and readings went to 18 psi low, and 150 psi high. Output temp
>>> now 74 degrees and still has bubbles in sight glass. I'm not sure I
>>> should keep adding since I'm already above the 14 psi recommended by
>>> the manual for this ambient temp, but what else could be happening? In
>>> order for me to hit the 35 degree level on the gauge, it would need to
>>> have a low side reading of 30 psi, well above the manual. I'm down to
>>> my last bit of R-12 and could probably only do one more evac and
>>> recharge, so I want to be fairly accurate with whatever I do next.
>>> Garry Parsley
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