Piper SEMINOLE PA-44-180, Maintenance Manual

Page: 170 / 881

Figure 21-25. Test Gauge and Manifold Set
TEST GAUGE AND MANIFOLD SET.
The proper testing and diagnosis of the air conditioning system require that a manifold gauge set be attached
into the system. This set consists of two gauges mounted to a manifold. One gauge is a high pressure gauge used
in the discharge side of the system. The other is a low pressure gauge used in the suction side of the system. The
manifold is a device having fittings for both gauges and connection hoses with provisions for controlling the flow
of refrigerant through the manifold. See Figures 21-25 and 21-26.
The center port of manifold set is used for charging or evacuation procedures, or any other service that may be
necessary.
Both the high and low side of the manifold have hand shut-off valves. When the hand valve is turned all the
way in, in a clockwise direction, the manifold is closed. The pressures on the side of the system will, however, be
recorded on the gauge above the hose.
Cracking the hand valve, in the counterclockwise direction, opens the system to the middle service port of the
manifold set. This is desirable only when it is necessary to let refrigerant out or into the system. Refer to Figure
21-25 and 21-26.
408
COMPOUND
PRESSURE GAUGE
TO SUCTION
SERVICE VALVE
TO VACUUM PUMP OR
REFRIGERANT CYLINDER
TO DISCHARGE
SERVICE VALVE
HIGH PRESSURE
GAUGE
PA - 4 4 - 1 8 0 / 1 8 0 T
AIRPLANE MAINTENANCE MANUAL
2 1 - 5 2 - 0 4
Page 21-59
Revised: May 15, 1989
1H2
PIPER AIRCRAFT