Process (Steps 1- 12):
1. Does the unit have a mechanical linkage arm between the return and outdoor dampers? If no, continue to the next step. If yes, then continue on to step 3.
2. This unit has a 0-50% Motorized Damper, and not an economizer. There is no mixed air sensor, thus the a 8 flash fault code should simply be ignored in this particular case.
3. Is the mixed air sensor connected to the MAT inputs on the Relitel Economizer Module (RTEM)? If no, continue to the next step. If yes, then continue on to step 5.
Image 1. RTEM
Image 2. MAT connection on the RTEM
4. Connect the two prong plug to the MAT inputs on the RTEM.
5. Pull the two pin plug from the MAT inputs on the RTEM and measure resistance across the two pins. If you read open (infinite resistance) or short (near zero resistance) replace the mixed air sensor.
WARNING:
Information in this article is intended for use by individuals possessing adequate backgrounds of electrical and mechanical experience and who comply with all federal, state, and local laws, rules, orders, or regulations related to the installation, service, or repair of a heating or central air conditioning product. Any attempt to install, service, or repair a heating or central air conditioning product may result in personal injury and/or property damage. The manufacturer or seller cannot be responsible for the interpretation of the information contained herein, nor can it assume any liability in connection with its use.