Most heater issues can be discovered by following our troubleshooting guide, which will save you time, money and aggravation. These tips apply to all makes and models of aircraft combustion heaters, including Janitrol Aero I-Series, B-Series, S-Series, CD-Series (C&D Associates Inc. designs) and Stewart-Warner South Wind.
Every heating system requires three key components to achieve proper operation: combustion air, ignition and fuel. If your heater is not working, one or more of these elements is deficient. By finding out which is lacking, the root cause of the problem can be determined.
Combustion air: This does not need to be measured precisely. Simply wave your hand a couple of inches under the exhaust. Airflow from the exhaust should be steady, and the output flow should feel like that of a standard hair dryer. Keep in mind that in flight, ram air supplements the blower to provide additional combustion air.
Ignition: Type I and Type II igniter plugs used in many Janitrol Aero B-series and S-series heaters should be replaced or have their gap set every two years. Type III igniter plugs used in all Janitrol Aero I-Series, CD-Series and Stewart-Warner South Wind heaters are not adjustable and should last the recommended life of the heater. To check, remove the lead from the spark plug and, while using rubber-handle pliers, hold the lead end approximately 1/4 inch from a ground. Have someone turn the heater on, and verify that the spark jumps at least 1/4 inch and is consistent, strong and blue in color. Reinstall the plug and move close to the exhaust, listening for a constant, strong spark. It should sound like an angry hornet trying to get out. Use caution as the heater could suddenly light. If checking the igniter gap, it is imperative to verify using the specific overhaul/owner’s manual. A typical Type I igniter should range between .050 and .060 inch and is adjustable. A typical Type II igniter should range between .156 and .315 inch and is adjustable. A typical Type III igniter should range between .080 inch .120 inch and is NOT adjustable, replacement being the only option.
Fuel: Fuel inlet pressure is often neglected in the combustion heater system. Ensuring proper fuel inlet pressure to your heater can add years to its life because overall reliability will be improved. Most Janitrol Aero I-Series, B-Series and CD-Series heaters require 6.5–8 PSI (except for turbine aircraft, which are 100–105 PSI). Original South Wind 8240, 8259 and 8472 series require 19–24 PSI. South Wind 8240, 8259 and 8472 series heaters overhauled under AMOC by C&D require 22–25 PSI. South Wind 940 series heaters require 1–15 PSI for carbureted engine aircraft and 20–35 PSI for fuel-injected engine aircraft. To test, “T” in a calibrated fuel pressure gauge just upstream from the heater’s fuel solenoid, and take a reading while the heater is running.
Once you’ve identified the problem areas, consult with the specific product overhaul or owner’s manual for the next steps. Or feel free to give us a call. Our technical support staff can help pinpoint your issue and provide additional troubleshooting information to resolve the problem with your specific model.