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Aircraft
Maintenance TroubleShoot >
Heater Troubleshooting (South Wind-except 8472 Series)
Heater operates on ground, but not in flight
1. Insufficient combustion air. Check ducts for obstruction. Check blower
motor for proper speed. Check fan blades for damage and freedom of rotation.
2. Weak ignition. Check spark plug. A good ignition system check may
be performed by using a long reach automotive spark plug opened up to a
3/32 inch gap. If the ignition system is operating properly the spark in
this gap will ignite a business card. Heater spark plug won't work for
this check due to the annular spark gap.
3. Lack of fuel. Check power to heater solenoid terminal (#8). If no
voltage is present, check thermostat calibration, air flow switch, and
cycling switch. Check fuel pressure between fuel pump and heater. Check
fuel supply to pump (remote solenoid, filter manual valves, etc.
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