- Staff
- #21
Sounds to me like a restriction in the system and a bad high pressure switch(switch in the back of the compressor). The low side should kick off at 20-22 and back on at 45-52. The high side should open the switch at roughly 350-375, 275 is low for it to kick out. The rapid rise in pressure sounds like the orifice is plugged, but the orifice being on the hot side of the condensor could also cause this rapid rise. On a truck the orifice tube should be in the outlet of the condenser(the lower tube that comes up and hooks up to the line going to the evap), and should be a white orifice if memopry serves me correct. On an 85 degree day you should see pressures of roughly 30-55 on the lw side at idle with the A/C on high MAX, and the high side should be in the 175-225 range. A rapid rise in pressure with throttle application is a direct indicator of a restriction(most likely plugged orifice or kinked line), and should be found right away as compressor death can occur quickly from this. Also make sure you radiator and condenser are clean and flowing air as low air flow will give VERY high high side readings.