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CHT Thermocouple Probe Wiring and Setup
Author: Matt Liknaitzky Reference Number: AA-00551 Views: 24916 Created: 2014-03-13 15:55 Last Updated: 2014-03-13 16:20 0 Rating/ Voters

Attached are settings and wiring connections for Cylinder Head Temperature senders. This guide can be used to help if you are experiencing problems or if you suspect your CHTs are reading incorrectly.

Remember to follow these 3 Steps first when troubleshooting senders.

CHT Troubleshooting Steps:

  1. Are senders wired with the correct polarity? Read this article
  2. Are senders in the correct channels? Read this article
  3. Is the correct Type thermocouple selected? Read this article
  4. A practical test you can do to determine if your CHT is reading correctly. Read this article

There are 2 common types of CHT - spark plug type and screw in threaded type. The threaded probes, also known as CHT Bayonet Probes are typically used on Lycoming engines.

Threaded CHT BAYO Probes:

  • Screw 3/8-24 Threaded CHT probes into recesses in cylinders (no washers required)
  • Use Thermocouple Channels TC5 through TC8 if you have a 4-cyl engine. Use TC7 through TC12 if you have a 6-cyl engine.
  • Remember that some CHTs are type-J thermocouples (these can be used). MGL Avionics supplies only type-K thermocouples
  • Remember that with type-K thermocouples that Yellow is Positive and Red is Negative

Wiring Instructions for Type-K Thermocouples:

Note: counter-intuitive colors






Select Correct Type in CHT setup (all MGL CHTs are type-K - some other manufacturers also use type-J)

Enigma/Voyager/Odyssey and iEFIS:


Infinity or Velocity Single:

IMPORTANT NOTICE: You must make your own determination if the products sold by MGL Avionics are safe and effective for your intended applications. MGL Avionics makes no representations or warranties as to either the suitability of any of the products we sell as to your particular application or the compatibility of any of the products we sell with other products you may buy from us or anywhere else, and we disclaim any warranties or representations that may otherwise arise by law. Also, we offer no specific advice on how to install any of the products we sell other than passing along anything that may have been provided to us by the manufacturer or other users. If you are in need of further information or guidance, please turn to the manufacturer, FAA Advisory Circulars and guidance materials, the Experimental Aircraft Association, or other reputable sources.