Installation of Gauges (Continued)
Be sure that the valve stem is turned all the way to the left, (counter-clockwise). Note that all attachments
are made while the valve is in this position, that is, with the gauge opening closed so that no refrigerant may
escape, or air leak into the system.
Remove the 1/4 S.A.E. flare cap from the body of the service valve. Note: Some compressors are
equipped with 1/8" I.P.S. pipe plug instead of 1/4" S.A.E. Flare Cap. If valve body is equipped with 1/8"
I.P.S. pipe plug, screw in 1/8" x 1/44" S.A.E. flare half union coupling.
Screw the nut of the connecting tubing on the fitting. With the nut still slightly loose at the gauge, crack the
service valve by turning it a fraction of a turn, just enough to let the refrigerant gas force air to the
connection, then tighten the gauge immediately. Use a solid wrench or a fixed wrench for turning the valve
Turn the stem, clockwise, until the gauge registers.
Start the compressor and read the lowside pressure on the compount gauge, and head pressure on the pressure gauge.
TO REMOVE GAUGES:
Close the valve all the way to the left.
Loosen the connecting tube, but to release the pressure and take off the gauge.
Replace 1/4" S.A.E. Flare Cap. If 1/8 x 1/4" S.A.E. flare half union coupling has been used, remove it and
replace 1/8" I.P.S. pipe plug.