Piper Navajo PA-31 Service Manual page 927

C469
TO LANDING GEAR
VENT AIR
"UP" LIGHT
CIRCUIT
BREAKER
RADIO NOISE
SWITCH FILTER
'I
CYCLING
SWITCH
HEAT DUCT SWITCH
HEATER
SHUTOFF
SWITCH
IGNITION
SWITCH (NC)
PLUG
AUTOMATIC
REST
PLUG
NOTE
107-16 SEE NOTE
USE ON B39D59 ONLY
RADIO NOISE
I
AIR BLOWER
Figure 13-18. Starting Power Circuit, B39D59, D39D59 Heater System
13-25. MAINTENANCE AND REPAIRS. 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.
13-26. COMBUSTION AIR BLOWER.
a. Removal:
1. Disconnect wire at quick-disconnect terminal.
2. Disconnect the inlet tubing from the inlet air adapter.
3. Loosen the clamps that hold the combustion air blower assembly in the support bracket and
slide the motor out of the bracket.
b. Replacing Motor Brushes: (Refer to Figure 13-30, 13-31 or 13-32.)
1. Remove the brush cap at one of the brush locations. Note position of brush inside the guide
and carefully lift
and brush the brush and brush spring out of the guide. Be sure to hold the brush so that it can be
reinstalled in precisely the same position if no brush replacement is required.
2. Inspect the brush for wear. A new brush is .531 inch long. If brushes are worn to a length of
.187 inch, they must be replaced.
Reissued: 10/12/79
HEATING AND VENTILATING SYSTEM
PIPER NAVAJO SERVICE MANUAL
5B21