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Page | 34
MM10001
Dated 1/1/08
Rev L dated 5/21/15
10 TESTING AFTER INSTALLATION OR OVERHAUL
10.1 GENERAL
A test of all components should be made after overhaul to ensure proper operations. If facilities
for measuring airflow, pressure drops, etc., are not available, the heater may be installed in the
aircraft. Provide a power source to maintain rated voltage during tests. Test should be run on the
ground and in the air to determine if operation is normal.
10.2 BENCH TESTING (SEE FIGURE 30.)
Required Equipment
• A test stand suitable for holding the heater is utilized. Choose a location where the
exhaust can exit freely from the heater.
• 7-10 psig fuel pressure source. 100 ± .5 for jet burners.
• Volt and Amp Meter
• A 12/24 VDC supply.
• Two water manometers (0-10.00 inches H
2
0) for measuring combustion and ventilation
air stream pressure.
• A piece of ducting, 24 inch minimum length, to be attached to the downstream end of the
heater. Install a 2-1/2 inch diameter opening at the outlet end. Provide openings for a
thermometer, thermostat duct switch and static tap 6 to 18 inches from the end of the test
duct.
• A 500°F thermometer. If testing in the aircraft, install temperature sensor into the outlet
plenum just aft of the heater. A small hole may be made in the plenum or duct for
insertion of sensor. After the test has been completed, close hole with high temp silicone.
• A 0-15 psig fuel pressure gauge for AV gas, or 0-200 psig for Jet fuel.
• A source of controls outlined in Figure 30. This simulates outside wiring of the heater
installation sufficiently to perform an operational test of the heater.
10.3 OPERATIONAL TEST
NOTE: Exhaust smoke during initial ground operation or testing is normal. The small amount of
smoke is expected due to limited combustion airflow on the ground. In flight, combustion air
is assisted by ram air and should burn clean.
NOTE: To reduce the risk of nozzle contamination, purge heater fuel delivery components and lines
prior to connecting to and operating heater.
Install heater in test set up or aircraft, making sure all connections are tight and secure.
Turn on master switch. Individually check the operation of the ventilating air blower,
combustion air blower and fuel pump.
Verify that the combustion air pressure switch is activated by checking for rated voltage
at terminal #2 for strips numbers 1-6 and terminal #7 for strips numbered 4-10. If not,
the combustion air blower is not providing sufficient air to actuate the combustion air
switch or the switch is improperly adjusted.
Check the ventilating air pressure water manometer. It should have a minimum reading
of 1.0 inches H
2
0 minimum at rated voltage. (Optional)
The combustion air water manometer should indicate approximately 1-7 inches H
2
0 at
rated voltage. (Optional)
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