Piper SEMINOLE PA-44-180, Maintenance Manual

Page: 188 / 881

PRESSURE RELIEF SWITCH.
The pressure relief switch automatically prevents the system from over pressurization by breaking the
electrical circuit to the magnetic clutch, stopping the compressor until pressure is reduced. The switch is located
in the line between the receiver and expansion valve and is actuated between 250 and 300 psi.
— Note —
Before relief switch is removed, the air conditioning system must be discharged.
ELECTRICAL INSTALLATION.
The electrical system wiring and components are installed and routed in the conventional manner. The wiring
harness is connected to switches in the climate control center on the right side of the instrument panel. The
harnesses cross the instrument panel to the left side where two wires are taken off for the compressor clutch. The
harness then passes aft along the fuselage where it connects to the evaporator motor, pressure relief switch and
the condenser blower motor.
Refer to Chapter 91 for air conditioning wiring schematic.
MANIFOLD PRESSURE SWITCH.
A pressure switch is provided in the manifold pressure gauge line in back of the instrument panel. The
purpose of the switch is to shut down the air conditioning system when the airplane is at full throttle enabling
maximum performance. No adjustment is necessary.
— END —
PA - 4 4 - 1 8 0 / 1 8 0 T
AIRPLANE MAINTENANCE MANUAL
2 1 - 5 3 - 2 0
Page 21-77
Revised: May 15, 1989
1H20
PIPER AIRCRAFT