I’m working through some issues with my AC system and reviewing the FSM. As I read it, they say to charge on the High Pressure side? I’ve never seen that before. Am I reading this right?
AC charging - high side?
- Thread starter Jcfields06
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- Thread starter
- #3
So if empty, charge on only High side with vehicle off? Okay to charge on low side when empty, with engine running?
Safest to charge through the low side. If you've pulled vacuum on the system, it should pull in enough once you hook up the can to over-ride the pressure switch and allow the compressor to engage and pull in the rest. Definitely don't hook up to the high-side while the compressor's engaged.
Hook up both gauges, running or not. If the the system is low, turn on the compressor and charge on the low side. If the system is empty, fill on the high side, or both sides, with the truck/compressor off. Top off as needed on the low side with the truck/compressor running.
The pressure will be too high when running to top off on the high side, hence charging on low with it running. If there is no pressure in the ac system(empty) the compressor will not even turn on due to a “fail safe” pressure switch. No harm at all trying to charge on the high side when running, you just wont be able to overcome the pressure the compressor builds as its pumping.
The pressure will be too high when running to top off on the high side, hence charging on low with it running. If there is no pressure in the ac system(empty) the compressor will not even turn on due to a “fail safe” pressure switch. No harm at all trying to charge on the high side when running, you just wont be able to overcome the pressure the compressor builds as its pumping.