I had originally added refrigerant, a whole can, and the suction pressure was still high. So then, thinking I had overcharged I let some out, now who knows how much refrigerant is in there.
So since the last poste I did a complete recharge on the system.
Followed all of the correct procedures, using a very good vacuum pump and high accuracy vacuum guage.
Actually weighed the refrigerant going in and the charge is about 10 grams short on an 650 gram charge. (I don't remember what the exact number was but I charged per the number under the hood)
The system now has the correct charge.
To diagnose the system I connected several temperature probes to the system lines.
The temperature probes were taped down on metal lines and insulated.
Following the system from the compressor.
The discharge line travels about 12 to 18 inches and enters the condenser.
The DISCHARGE PRESSURE port is in this span a few inches from the condenser inlet.
The CONDENSER INLET TEMPERATURE was taken a couple of inches from the condenser inlet.
The CONDENSER OUTLET TEMPERATURE was taken a couple of inches from the condenser outlet.
From here the line travels about 8 inches to the orifice tube.
The SUCTION PRESSURE port is a few inches after the orifice tube.
The SUCTION TEMPERATURE was taken adjacent to the SUCTION PRESSURE port.
From here the line travels (uninsulated) about 2.5 feet to the evaporator inlet.
The line exits the evaporator and goes directly into the suction accumulator.
The line out of the suction accumulator travels about 12-18 inches to the compressor.
The EVAPORATOR OUTLET TEMPERATURE was taken just after the suction accumulator.
The following are the readings taken after the recharge.
-Fan on high
-System running for 10 minutes or more
-Several sets of readings taken and remained constant.
DISCHARGE PRESSURE 225 psi
CONDENSER INLET TEMPERATURE 171 F (About 32 Superheat)
CONDENSER OUTLET TEMPERATURE 120 F (Good heat rejection across condenser)
SUCTION PRESSURE 64 psi (This is too high right? )
SUCTION TEMPERATURE 71 F (Chart says says PSI should be 71 so maybe slight superheat here but maybe temp and/or pressure gage slightly off)
EVAPORATOR OUTLET TEMPERATURE 102 F (This shows that the evaporator is absorbing heat)
CENTER VENT TEMPERATURE 76 F (My Plymouth van was making 62 immediately prior in the same ambient conditions)
AMBIENT TEMP DIRECTLY IN FRONT OF THE CONDENSER 93 F
Later I went out and took temperatures in three places.
1. Directly after the evaporator (which is directly before the accumulator)
2. Directly after the accumulator
3. Directly before the compressor
This showed about a 10 F rise in this span which may indicate that the refrigerant is leaving the evaporator as a gas and picking up superheat along the way to the compressor.
The compressor is quiet and doesn't seem to make excess noise.
Sure would like to know for sure what is wrong with the system so I can replace the right thing the first time.
For what it's worth,
This system is somewhat different from my Plymouth Van which is as follows.
The compressor outlet goes into the condenser
From the condenser the line goes into some kind of small vessel. Possibly a drier.
From there the line goes into a TX valve which is directly before the evaporator. The high pressure port is located in this line after the condenser and before the TX valve.
The line then goes directly to the compressor with no accumulator. The suction port is in this span between the evaporator and the compressor.
Friday, July 23rd, 2010 AT 11:42 PM