Gauges are the only accurate means of determining what is going on inside the unit. No service operations other than the
most simple one should be performed without installing gauges.
There are two types of gauges, and both are necessary:
A pressure gauge for the discharge side of the compressor (also known as "highside" gauge).
A compound gauge for the suction side of the compressor (also known as the "lowside" gauge).
The compound gauge reads from 30 inches of vacuum to 60 pounds pressure. With this gauge installed, it is possible to
determine the lowside pressure settings, the vacuum pumping ability of the compressor, when all refrigerant has been
removed, to diagnose instruction book.
The pressure gauge reads from zero pounds to three hundred pounds. It determines the pressure pumping ability of the
compressor; leaky discharge valves, air in the system and other points covered in this installation book.
For correct calibration of gauges, before attaching to equipment, the needle should point to zero
(0) when the gauge caps are removed in atmospheric pressure.
INSTALLATION OF GAUGES
Gauge installation is not difficult, and the same method is followed in putting on either type.
Remove the cap covering the valve stem, being careful not to lose the sealing washers or gaskets.