Auto Air Conditioning & Heater Repair: ADual aircon system normal gauge pressure, psi difference, gauge pressure

Question
I would like to ask
1). What is the normal high side and low side pressure for a dual aircon system if measure at the point near the compressors?

2). What is the low side pressure if measured near the outlet of the first evaporator before the t joint of the 2nd evaporator?

Answer
Hi Bots

1. low pressures between 25 and 45 psi and high 175 to 225 psi.  Dependant on ambient temperature the higher the temp. the higher on the scale the psi.

Sorry where this a one there should also be a two.

2.  The readings should be between 3 and 8 psi difference it all has to do with the distance from the compressor.  So to say that the front has better reading then the back is impossible because the front unit may be closer or vise versa.  You will have a difference but very little.  With having the both ports you can determine which one is causing the problem if you have any rather then guessing.