- *LCU Why do I have CO2 sensor failure, but don't have one installed?
1. Do you have a 2 flash code on your Reliatel Refrigeration Module (RTRM) or your Economizer Module (RTEM)? If RTEM continue on to the next step, if RTRM go to step 4.
Image 1. RTRM Image 2. RTEM
2. Do you have something wired to the DCV pins on the RTEM? If yes continue to the next step, If no replace the RTEM and jump to end.
3. It looks like you do have a CO2 sensor installed. Check DC voltage across the two DCV pins (with wires still attached). If you measure 0VDC (short) or 10VDC (open) then you should verify proper wiring. If wiring is correct then replace the CO2 sensor. Jump to End.
4. What can cause a 2 flash code on the RTRM?
5. End.
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.