Aircraft Heater Technical Support:
We have all this information stuck in our heads and we want it out!
C&D would like to make troubleshooting assistance easily accessible for everyone. Please take a look around this section as you will find the most common troubleshooting guides for C&D, Janitrol and SouthWind/ Stewart Warner Aircraft Heating Systems.
When troubleshooting, knowing which direction to take will save everyone involved time, money, and aggravation. Ninety percent of all heater failures can be found by following a logical order of troubleshooting. The proceeding troubleshooting tips for the most part are listed in order of ease of accomplishment and focus more on the Janitrol B series, SouthWind 8240-8472 series, and C&D Associates, Inc. heaters as these make up the majority of general aviation aircraft. The principals, though, apply to all combustion heaters.
Like anything else that is somewhat complex, a heater can be intimidating when it comes to determining why it is not working correctly. This is especially true if some basic guidelines in troubleshooting procedures are not followed.
So here are the basics:
Every heating system requires 3 key components to achieve proper operation. They must have combustion air, ignition, and fuel. If your heater is not working, one or more of these elements is deficient. By finding out which of these three elements is lacking, the problem can be determined in just a few minutes. In order to complete a thorough analysis of heaters operation , three pieces of test equipment will be needed. A volt meter or light for checking rated voltage, a quality fuel pressure gauge and a 0-500° temperature gauge.
- Combustion air: Generally 1/2" to 8” inches of water is sufficient. This does not need to be measured with a water manometer; simply wave your hand a couple inches under the exhaust. Airflow from the exhaust should be steady, and the pressure output should feel similar to a standard hair dryer. Keep in mind that in flight, ram air supplements the blower to provide additional combustion air. Unfortunately ram air also prematurely will wear out older heater motors as the blowers continue to pin-wheel even with the heater off.
- Ignition: First things first here, all Janitrol B-series and S-series igniter plugs should be replaced and have their gap set every two years. This should fix most of your problems. If not, remove the lead from the spark plug and using rubber handled pliers (very important if you like your mechanic) and hold the lead end approx. 1/4” from a ground. Have someone turn the heater on and verify that the spark jumps at least 1/4”, is consistent, blue in color and strong. Another simple way to check for ignition, move close to the exhaust; see if you notice the sound of a constant, strong spark. It should sound kind of like a wet hornet trying to get out. Use caution with this method though as the heater could suddenly light off. You can usually identify the mechanic who has done this procedure incorrectly by the resultant lack of facial hair.
- Fuel: Fuel pressure is the neglected step child of the combustion heater. Annually ensuring proper fuel pressure to your heater can add years to its life (and many times your marriage) because overall reliability will definitely improve. Most Janitrol B series and C&D Associates heaters require 6.5-8 PSI (turbine aircraft 100+5-0 PSI). South Wind 8240-8472 series must have 22 PSI or above. Its relatively simple to “T” in a quality fuel pressure gauge just upstream from the heaters fuel solenoid, and take a reading while the heater is running.
These basics should get you started on your way to less frustration. If not, take a deep breath and consult the following troubleshooting guide for a more detailed analysis. And as always, you are welcome to give us a call. Our technicians have been extremely well trained not only to pinpoint the issue but also to talk you off the edge and provide suggestions that are certain to pull you through this difficult time.
VIEW: Janitrol Troubleshooting