Piper Navajo PA-31 Service Manual page 925

Figure 13-15. Primary Power Circuit, B39D59, D39D59 Heater System
13-24. HEATER POWER CIRCUIT CHECK.
a. With the HEATER SWITCH in the HEAT position, electrical continuity should be present at the
following locations: (Refer to Figures 13-16, 13-17 or 13-18.)
NOTE
Power for the ventilating air blower is the same as described above
except that power is now supplied through the HEAT side of the
HEATER SWITCH.
1.
Terminal No. 1 of the heater terminal strip.
2. 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.
3.
From terminal No. 3 of the overheat switch through the combustion air pressure switch to
terminal No. 2 of the heater terminal strip.
4.
From terminal No. 2 of the heater terminal strip through the radio noise filter to the
ignition unit; to the shut off valve; and through the adjustable duct switch to terminal No. 3 of the heater
terminal strip. Radio noise filter is on 39D59 heater systems No. 1 and No. 2 only.
5.
From terminal No. 3 of the heater terminal strip through the cycling switch to the fuel
solenoid valve.
wiring must be traced back to the power source. If components are still inoperative after the wiring
inspection, check the individual inoperative components for continuity and, if necessary, replace them.
Reissued: 10/12/79
HEATING AND VENTILATING SYSTEM
PIPER NAVAJO SERVICE MANUAL
5B19