Charging vintage air system

[jblaine86]

Tried to charge vintage air system this weekend and need some help. I am new to charging ac systems. I vacuumed the system and that went well. My problem occurred while trying to charge system. The compressor binary switch will not let compressor turn on. Any ideas or what should gauges read?
Thank You
Jon

[CJD Automotive]

Depending on ambient temps, your looking for 25-40 lbs. low side and 200-275 high side. Your cooling fan placement and how well the condenser is sealed to the other coolers will affect that number when sitting stationary. Less cooling on the condenser will mean a higher high side pressure.

You said you evacuated the system, did you leave the gauges attached and see if it loses vacuum once completed?

The low pressure switch is probably a 10-20 psi piece, so as long as it is taking refrigerant, shouldn't be an issue. It will fast cycle if it's low. Make sure you have the high side manifold closed if compressor is running. That being said, I really recommend you take it to a shop that can measure the amount of refrigerant and properly evacuate the system. Your talking less than a hundred bucks. Over or under on charge, even a few tenths, makes a dramatic difference on cooling efficiency with todays small systems.