Installation Of Heater; Heater Electrical System Check; Electrical Continuity Check - Piper Navajo Chieftain PA-31-350 Service Manual

NAVAJO CHIEFTAIN SERVICE MANUAL
i. Disconnect the fuel drain and allow it to drop down.
j.
Disconnect the duct switch and cabin heat control cables.
k.
Disconnect the defroster and heat ducts from the air-heat distributor box.
1.
Loosen the clamp that secures the heater to its mounting bracket and remove the heater from the
airplane.
13-19. INSTALLATION OF HEATER.
a. Position the heater on its mounting bracket and secure with clamp.
b.
Attach the forward end of the heater to the fuselage bulkhead.
c. Connect the air inlet valve cable to the forward end of the heater. On models with Serial
Numbers 31-7305104 to 31-7652123 inclusive and 31-7652125 to 31-7852071 inclusve, adjust door to
open 3 to 4 inches when control is pushed to the full open position. Upon completion of adjustment, check
operation.
d.
Connect the fuel line to the heater and install shroud cover.
e. Connect the fuel drain to the underside of the heater.
f. Position the combustion air blower, connect tubes and secure the unit to its mounting bracket.
g. Connect the defroster and heat ducts to the air-heat distribution box.
h.
Connect the heat control cable to the control arm located on the air-heat distribution box.
Adjust the cable so that when the door is completely closed, approximately .062 to .125 inch springback
exists between the control lever and lever stop.
i. Connect the duct switch control cable to the switch on the right side of the air-heat distribution
box. Adjust the cable so that when the control lever is full against its stop the control arm aligns with the
vertical line of the switch. (Do not loosen the alien set screw that secures the arm to the switch shaft.) Move
the lever to the extreme right to ascertain that the control arm on the duct switch will have a 105
°
1
°
travel to high heat position.
j. Connect the electrical leads to the heater. (Awiring schematic of the heater hook-up may be
found in the Electrical System Diagram, Section XI.)
k. Operate the heater long enough to determine that the unit is operating properly.
1. Install the access panels in the baggage compartment and at the side of the fuselage.
13-20. HEATER ELECTRICAL SYSTEM CHECKS.
13-21. ELECTRICAL CONTINUITY CHECK.
These tests are listed as an aid in isolating open circuited or inoperative electrical components should
the heater fail to light with the HEATER switch energized.
NOTE
The schematic wiring diagrams (Refer to Figures 13-6 thru 13-8)
show. in addition to the heater circuitry. a suggested aircraft control
circuit. For the purposes of this manual, the circuitry shown in these
illustrations will be utilized to describe electrical continuity checks.
It must be assumed that power. which is furnished through the heater circuit breaker, is present at the
H EATER switch at all times. Always check the circuit breaker before performing electrical continuity checks.
Revised: 10/15/82
4B15
EATING AND VENTILATING SYSTEM