Piper Navajo PA-31 Service Manual page 935

PIPER NAVAJO SERVICE MANUAL
b. Installation:
1. Install the limit switch and spacers (gaskets) by placing them in position in the heater jacket
opening and installing two screws.
NOTE
After installing the overheat limit switch visually check to make
sure that the switch does not come in contact with combustion
chamber. Clearance is .075 ± .015, if less shim by adding 14D29
gaskets, if maximum clearance is exceeded, shave material off
gasket to obtain clearance.
2. Tighten screws securely; then reconnect the electrical leads in accordance with markings
made during disassembly. (If in doubt about electrical connections, refer to the wiring diagram, Figure
13-10, 13-11 or 13-12.)
3. Install the cycling switch by placing it in position in the heater jacket opening and securing
it with the two screws. Tighten screws securely; then reconnect the electrical leads to their respective
terminals as marked during disassembly. (If in doubt about connections, refer to wiring diagram, Figure
13-10, 13-11 or 13-12.)
13-35. COMBUSTION AIR BLOWER SWITCH. (Refer to Figure 13-28 or 13-29.)
a. Removal:
1. Disconnect electrical leads from the terminals at the combustion air blower switch mounted
on bulkhead (Sta. 59) being sure to mark them for proper reassembly.
2. Disconnect the tube assemblies from the switch and mark them also for proper reassembly.
3. Remove the two screws securing the switch to the bracket and remove the switch from the
airplane.
b. Installation:
1. Install the switch onto the bracket at bulkhead (Sta. 59) being sure that the adjustment side
faces to the outboard surface and the outlet marked (HIGH) is in a horizontal position and the other outlet
is pointing to the bottom on the airplane. Secure the switch to the bracket with the two screws previously
removed.
2. Connect the tube assemblies to the switch using a suitable thread lubricant.
3. Connect the electrical leads previously removed to the switch.
13-36. COMBUSTION AIR PRESSURE SWITCH. (Refer to Figure 13-27, 13-28 or 13-29.)
a. Removal:
1. Disconnect electrical leads from the terminals of the combustion air pressure switch, being
sure to mark them for proper reassembly. Disconnect the tube from the switch cap. Exercise caution not to
exert excessive bending of the tube. (It is "tacked" to the combustion chamber inside the jacket.)
2. Unscrew and remove the combustion air pressure switch from the fitting on the combustion
air inlet tube.
b. Installation:
1. Install the combustion air pressure switch by rotating it on the threaded fitting of the
combustion air inlet tube and tighten it securely. Exercise caution not to over-torque the switch as this
could change the setting.
2. Connect electrical leads to their respective terminals in accordance with markings made
during removal. If in doubt regarding proper connections, refer to wiring diagram, Figure 13-10, 13-11 or
13-12. Connect the tube to the switch cap.
3. Check for proper heater operation.
Revised: 1/29/82
HEATING AND VENTILATING SYSTEM
5C5