amphicar770

hi all,

Below is a message I posted to autoacforum. I have since tried clamping the heater hoses but am still seeing no better than about 50 degree vent temps even after replacing compressor, etc.

Pressures seem fine (low drops to around 25 when I turn off blower fan). Here is the link and original message I posted to autoacforum. Thought I would try here in case there is an A-body factor I should consider. Any ideas appreciated.

Thanks.


http://www.autoacforum.com/messagevi...threadid=31032


Year: 1968
Make: Olds
Model: Cutlass
Engine Size: 350
Refrigerant Type: R12
Ambient Temp: 94
Pressure Low: 55
Pressure High: 210
Country of Origin: United States
Hi All,

Hope the experts can help.

Recently replaced the compressor on my 1968 Cutlass Vista Cruiser with a Pro6Ten. At the same time I replaced all the hoses with new, removed and flushed the condenser which was pretty clean, new expansion valve, new drier, and a cleaned calibrated POA valve from one of the classic air places. I changed the oil in the Pro6Ten to mineral oil. I am using R12. It is charged with 4 lbs as measured on a refrigerant scale.

My vent temps are still not much better than about the low to mid 50's. A few notes (which hopefully help rather than bias).

The first POA valve I received was filthy. Seems like a core got mixed in with the "rebuilt" units. I contacted vendor and returned it, they sent it back supposedly cleaned and calibrated. It was still not as spotless inside as I would have expected but seemed OK. The initial error does make me wonder how careful they are about cleaning and calibrating or if I could have gotten it back set to R134. Maybe I should have used the original which did not look bad.

A stupid mistake on my part after reading the factory shop manual. The first time I charged it I did so as liquid (30 lb drum upside down). I wound up having to reclaim and recharge again, this time from the gas side (canister up). While compressor makes no strange noises of any sort, I suppose it is possible that I mucked something up.

I am thinking that the low pressure side whole be closer to 30 but it been closer to between 55-60. High side of around 210 seems about right?

Any ideas or help greatly appreciated.

Thanks.

MDchanic

Okay, I read the AutoACForum thread.

Let's get this started. Others with more experience will, I'm sure, add to it.

First, there is mention in the other thread of the recirculation settings not really being designed to recirculate. From what I can see looking at the diagrams, and what I recall from taking these apart, in Max mode, outside air should be essentially completely screened out.

Second, have you consulted the performance chart on page 1C-14 of the CSM?
You state 94°F, but give no relative humidity reading. The humidity is extremely important, as energy removed from the air to condense the water in it cannot also be removed to reduce its temperature.

Since your info says you're in PA, I will ASSume a RH of about 80% when it's 94° outside. If I do, the chart says that you should expect a low pressure at the POA of 31psi and a head pressure of 251psi, at 2,000 RPM, with a temperature of 64.5°F at the RH air duct.

I'd check your weather and the chart, and work from there.
No sense spinning your wheels trying to make the system do what it was never designed to do.

- Eric