Piper SEMINOLE PA-44-180, Maintenance Manual

Page: 131 / 881

HEATER POWER CIRCUIT CHECK.
1. With the HEATER SWITCH in the HEAT position, voltage should be present at the following locations:
(Refer to Figure 21-9)
— Note —
Power for the ventilating air blower is the same as described, except that power is now
supplied through the HEAT side of the HEATER SWITCH.
A. Terminal No. 1 of the heater terminal strip if the air valve is open.
B. From terminal No. 1 of the heater terminal strip through the radio noise filter to the combustion air motor
and to terminal No. 1 of the overheat switch.
C. From terminal No. 3 of the overheat switch through the combustion air pressure switch to terminal No. 2
of the heater terminal strip.
D. From terminal No. 2 of the heater terminal strip to the ignition unit to the fuel regulator and shutoff valve
and fuel pump through the adjustable duct switch to terminal No. 3 of the heater terminal strip.
E. From terminal No. 3 of the terminal strip through the cycling switch to the fuel solenoid valve.
In the event that voltage is not present at one or more of the above listed points, the wiring must be traced back
to the power source. If components are still inoperative after the wiring inspection, check the individual
inoperative components for voltage and, if necessary, replace them.
GENERAL MAINTENANCE.
Instructions in this paragraph pertain to maintenance of the basic heater and components while the heater is
installed in the airplane. Instructions for removal of components are included provided the installation permits
accessibility.
— Note —
No special service tools are required for normal periodic maintenance.
COMBUSTION AIR BLOWER.
1. Removal:
A. Disconnect wire at quick disconnect terminal.
B. Disconnect the inlet tubing from the inlet air adapter.
C. Loosen the clamps that hold the combustion air blower assembly in the support bracket and slide
the motor out of the bracket.
PA - 4 4 - 1 8 0 / 1 8 0 T
AIRPLANE MAINTENANCE MANUAL
2 1 - 4 3 - 11
Page 21-20
Revised: May 15, 1989
1F11
PIPER AIRCRAFT