a/c system pressure readings
08-09-2015, 08:55 AM
#1
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a/c system pressure readings
I checked my a/c pressures and have the following results:
outside temp - 95 degrees, 50 RH
fan speed 3 @ idle -low 43/ high 230, vent ~ 55 deg
fan speed 3 @ idle - low 30 / high 260, vent ~ 55 deg
fan speed 4 @ idle - low 50 / high 250, vent ~ 60 deg
fan speed 4 @ 1500 rpm - low 40 / high 280, vent ~ 60 deg
I am wondering how these values compares to others. The high side pressure seem a little high (compared to charts I have seen) and I am trying to figure out if it is due to a restruction in the orifice tube (which seems common), blend door, over charge, or something else. I checked pressures at both fan speed 3 and 4 because I found there was a difference in the temp from the vents. Maybe this is the best the system can do. Does anyone have simliar data to compare?
outside temp - 95 degrees, 50 RH
fan speed 3 @ idle -low 43/ high 230, vent ~ 55 deg
fan speed 3 @ idle - low 30 / high 260, vent ~ 55 deg
fan speed 4 @ idle - low 50 / high 250, vent ~ 60 deg
fan speed 4 @ 1500 rpm - low 40 / high 280, vent ~ 60 deg
I am wondering how these values compares to others. The high side pressure seem a little high (compared to charts I have seen) and I am trying to figure out if it is due to a restruction in the orifice tube (which seems common), blend door, over charge, or something else. I checked pressures at both fan speed 3 and 4 because I found there was a difference in the temp from the vents. Maybe this is the best the system can do. Does anyone have simliar data to compare?
08-09-2015, 09:24 AM
#2
The pressures seem to be ok. Is the ac not cooling? If the ac isn't cooling like it should, you can hook up the gauges and with the truck running spray the condenser with a water hose. If pressures drop dramatically then this shows you're low on freon and the fan clutch is not pulling enough air across the condenser.
08-09-2015, 10:22 AM
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I just saw I had a typo. The second reading for fan speed 3 was at ~ 1500 or 2000 rpms (not idle).
I have seen charts that say the high side pressure should be 185 to 270 psi based on humidity over 40% and others that say 275 to 300 psi is normal for high side at 95 degrees. The truck is cooling OK but still not like other vehicle checked the same day under same conditions. The other vehicle was blowing ~40 to 45 deg from vent, the truck is blowing 55 to 62 deg from vent.
I have seen charts that say the high side pressure should be 185 to 270 psi based on humidity over 40% and others that say 275 to 300 psi is normal for high side at 95 degrees. The truck is cooling OK but still not like other vehicle checked the same day under same conditions. The other vehicle was blowing ~40 to 45 deg from vent, the truck is blowing 55 to 62 deg from vent.