100-Hour Inspection; Heating And Ventilating System Maintenance And Service; Removal Of Heater - Piper Navajo Chieftain PA-31-350 Service Manual

NAVAJO CHIEFTAIN SERVICE MANUAL
13-16. 100-HOUR INSPECTION.
The mandatory
100-Heater Operating
Hour Inspection shall be
conducted on new heaters or overhauled heaters with a new combustion tubeassembly upon the accumulation
of 500-heater hours or twenty-four months. whichever occurs first, and thereafter at intervals not to exceed
100-heater hours or twenty-four months. whichever occurs first. If an hourmeter is used on the heater
assembly. it should be connected across terminals number 2 and 5 on the heaterterminal strip. If an hourmeter
is not used. count one heater hour for each two flight hours for normal aircraft operation. Consideration
should be given for any excessive ground operation of the heating system.
NOTE
The 100-Hour Inspection consists of the functional checks and
inspections listed below and the Pressure Decay Test.
a. Inspect ventilating air and combustion air inlets and exhaust outlet for restrictions and security at
the airplane skin line.
b.
Inspect the drain line to make sure it is free of obstructions. Run a wire through it if necessary to
clear an obstruction.
c. Check all fuel lines for security at joints and shrouds. making sure that no evidence of leaks exists.
Also check for security of attachment of fuel lines at the various attaching points in the airplane.
d. Inspect electrical wiring at the heater terminal block and components for loose connections.
possible chafing of insulation. and security of attachment points.
e. Inspect the high-voltage cable connection at the spark plug to make sure it is tight. Also. examine
the cable sheath for any possible indications of arcing. which would be evidenced by burning or discoloration
of the sheath.
f. Inspect the combustion air blower assembly for security of mounting and security of connecting
tubing and wiring. Tighten any loose electrical terminals and air tube connections.
g. Operate both the combustion air blower and ventilating air blower and check for unusual noise
or xibrations.
h. It is recommended that the condition of the spark plug be checked for operation as described in
paragraph titled "Spark Plug."
i. Evaluate the condition of the combustion chamber by performing a "Pressure Decay Test" as
described in Janitrol Maintenance and Overhaul Manual P N 24E25-1 dated October 1981 or Kit 764 963.
Janitrol Heater Pressure Check.
i. Following the 100-hour inspection. perform the "Preflight and. or Daily Inspection"as described.
13-17. MAINTENANCE SERVICE. Instructions contained in this section consists of periodic inspection.
adjustments. and minor corrections required at normal designated intervals for the purpose of maintaining
the heating system in peak operating condition. These inspections assume that a heating system includes
accessory components mentioned in preceding paragraphs.
13-18. REMOVAL OF HEATER.
a. Turn the heater control switch off.
b. Remove the access panel located on the right side of the nose section.
c. Open the forward baggage door and remove the access panel located on the right rear side of the
baggage compartment door.
d. Loosen the shroud cover of the fuel inlet line fitting located on the forward upper left side of the
heater. Disconnect the fuel line from the heater.
e.
Remote the screws that secure the forward end of the heater to the fuselage bulkhead plate
assembly.
f. Disconnect the air inlet valve cable attached to the forward end of the heater.
g. Disconnect the electrical leads from the heater. (Identify the lead connections to facilitate
reinstallation.)
h.
Disconnect the combustion air blower inlet tube from the blower and the tube between the
blower and heater.
Revised: 10/5/83
4B13
HEATING AND VENTILATING SYSTEM