Piper Navajo PA-31 Service Manual page 919

PIPER NAVAJO SERVICE MANUAL
383
384
Figure 13-8. Top View - Duct Switch
39D59 Heater System No. 1
Figure 13-9. Top View - Duct Switch
39D59 Heater System No. 2, B39D59
and D39D59 Heater System
13-13. OPERATING CONTROLS.
NOTE
The schematic diagram (Figures 13-10, 13-11 or 13-12) shows the
heater circuit, including the electrical wiring in the airplane.
a. The HEATER SWITCH is connected in the line that supplies electrical power to all heater
equipment and controls. When this switch is in the OFF position, the entire heater system is inoperative.
This switch has a FAN position which permits use of the ventilating air blower to circulate cool air through
the system for summer ground operation. With the switch in FAN position, the heater is inoperative and
only the ventilating air blower is energized.
b. The HEATER SWITCH is a normally open switch that supplies power to (lock-in) the safety
relay through which power is supplied to the ignition and fuel circuits of the heater.
Reissued: 10/12/79
HEATING AND VENTILATING SYSTEM
5B13