What It Means
- Defrost time > 20 minutes
Lennox Zone controller
Lennox Error Code 0100
Zone controller
Causes & actions from Lennox
How it shows
- harmony diagnostic led1234: 0100 (led1: off, led2: on, led3: off, led4: off)
The defrost board should never allow a defrost for greater than 20 minutes. If this error occurs, check the outdoor unit to see if it is stuck in defrost mode. The zone control system will use the backup heat during this error and not the heat pump.
Applicable models & manual sources
- HARMONY III
Defrost time > 20 minutes
HARMONY III, X9953
Disclaimer: This information is for general reference. Code wording and instructions vary by model. Always follow the service manual for your exact unit.
What should you check next?
Continue in ACLogics with guided diagnosis for your equipment and symptoms.
