Piper Navajo PA-31 Service Manual page 949

PIPER NAVAJO SERVICE MANUAL
19. Rotate the combustion air switch (12) onto the threaded fitting on the combustion air tube
and tighten it firmly.
20. Slide the grommet (27) over the combustion air tube and connect the tube to the elbow
fitting (11) on the combustion air pressure switch (12). If necessary, split the grommet for easier
installation.
21. Install the wiring harness and connect all wire leads to their respective terminals. (Refer to
the wiring diagram, Figure 13-10 or 13-11.) Place the grommet (27, Figure 13-27 or 13-28) in position in
the jacket (17); locate the ventilating air blower (29) at the end of the jacket. Thread the quick-disconnect
on the wiring harness through the grommet (27) and connect it to the mating connector on the motor lead.
22. Place the blower housing in position on the jacket assembly (17) and secure it by installing
the four screws (28), if removed at disassembly. This operation is easier if the screws (28) are started into
their threads and the blower housing rotated into place, allowing the screws to enter the notched openings
in edge of blower housing. Tighten all screws securely.
23. Install the elbow adapter (2) with the screw (56).
b.
Reassemble the B39D59 heater giving special attention to the following instructions: (Refer to
Figure 13-29.)
1. Insert the ventilating air motor (13) into the motor bracket assembly (19), slide the blower
fan (17) on the end of motor shaft and rotate it until the set screw is aligned with the flat side of the motor
shaft. Tighten the set screw just tight enough to hold it at this time.
2. Attach the capacitor and leads (18) to the motor bracket (19) with the screw. Make sure a
good electrical ground connection is made at this point Install ground bracket (44) and three new fasteners
(43). Insert this assembly into the blower housing (12).
3. Make sure all wires are routed and grommeted as they were prior to disassembly and then
secure the assembly in housing with three screws (42).
4. The motor (13) should be positioned in the bracket (19) to locate the blower fan (17)
properly in the blower housing (12). The blower fan should be positioned so it will rotate freely and just
clear the contoured spill plate in the blower housing. Tighten the alien-head set screw and spin the blower
wheel by hand for a clearance check. Then apply appropriate voltage to run the motor as a final clearance
check.
5. Place a new rope gasket (31) in position on the exhaust outlet, spring the jacket assembly
(5) open at the seam and insert the combustion tube assembly (7) carefully into the jacket. Exercise care to
clear the pressure switch tube in the exhaust outlet and see that the rope gasket (31) is properly located.
Close the gap on the jacket assembly and install screws to secure it at the seam. (Solenoid lead grounds
under these screws. See notations made during disassembly.) Make sure the seam is in good condition and a
tight fit is effected.
6. Install cable straps at locations noted during disassembly.
7. If new spray nozzle is not being installed, remove the original nozzle (21) from the
polyethylene bag. Screw the nozzle into nozzle holder and tighten to 75-100 inch-pounds. It is very
important to torque the nozzle to this value as incorrect tightening could cause improper heater operation
and "drool."
CAUTION
The spray nozzle has a slight protrusion on the nozzle face. If this
area has been struck by any object which would make a dent or
destroy the original contour, the nozzle must be replaced.
8. Install a new head gasket (30) and the head assembly (6) to the combustion tube assembly
(7) with the six attaching screws.
Reissued: 10/12/79
HEATING AND VENTILATING SYSTEM
5C19