The E0 an E01 error codes are typically related to the incoming supply voltage. The error is reporting a problem with the voltage Leg-to-Leg or phase rotation.
| Faulty code | E0 / E01 E0 Power Phase / E01 Reverse Fault |
| Model | All |
| Name | Power phase loss/reverse fault |
| Classify | Power supply issue |
| Possible cause | · Power supply is incorrect (Lack of phase, phase stagger) |
1.How to diagnose the E0 error code.
With your meter, first measure incoming voltage at the disconnect switch on the line side. Measure voltage Leg-to-Leg and Leg to ground. Verify voltage match's unit nameplate rated voltage on the Leg-to-Leg measurements. If the voltage is correct, you can now power the unit and verify the voltage at the XT1 terminal block again match's Leg-to-Leg voltage measured at the line side of the disconnect switch. If there is an issue on the Leg-to-Leg voltage or a phase is missing, correct issue to resolve error code E0.
XT1 Terminal Block
2. How to diagnose a E01 error code.
An E01 error is usually an issue with the phases are reversed and rotation is incorrect. This can be checked with a Phase Rotation Meter. If a phase Rotation Meter is not available, you can change rotation by switching two legs on the disconnect load side or the field wiring on the bottom of the XT1. Typically switching L1 & L2 will resolve the issue with rotation.
3. How to verify voltage on the DC Fan Module / Phase Monitor
After the above steps have been verified it is recommended to check the CN11 plug on the DC Fan Module board. Verify leg-to-Leg voltage is correct and the plug is installed correctly. If voltage is incorrect or a phase is missing locate issue and replace harness if necessary.
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.