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Low Side Pressure High But Cools WELL!

tperk100 on Mon October 24, 2011 4:43 PM User is offline

Year: 2004
Make: ford
Model: f350
Engine Size: 6.0
Refrigerant Type: 134
Ambient Temp: 75
Pressure Low: 100
Pressure High: 150
Country of Origin: United States

Had a leak...replaced O ring at evap / accum connection ..fixed leak.

At same time decided to replace orifice with next smaller size. Old orifice was extremely difficult to remove ....probably because it was installed BACKWARDS! yours truly about 4 months ago.

Put all together, evacuated and charged by weight. Now low side pressure at 75 ambient is 100 psi....about double what is should be. Ford diagnostic procedures suggest that the orifice o-rings are missing / defective. There were definitely o-rings on the new orifice.

What is really baffling me is that the vent temperature in the cab is 38 DEGREES!!! the system is cooling well. you think I have anything to worry about? My tendency is to let it ride.tperk1000

Posts: 8
Joined: Sun Jul 24, 2011 9:57 am
Favorite Refrigerant: 134A
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Tom P

mk378 on Tue October 25, 2011 9:03 AM User is offline

That reading must be wrong. If the pressure really were 100 you would have no cooling. Assuming that you are using the manifold correctly with the handwheel valves CLOSED to measure pressure, maybe the coupler is not opening the shrader valve on the truck.

NickD on Thu October 27, 2011 9:27 AM User is offline

Never found fault with P-T charts, 100 psi low side should give you a minimum vent temperature of 125*F with R-134a.

Something is amiss.

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