Outdoor Unit Fault Led's; Outdoor Unit Fault Led 1 Flash; Outdoor Unit Fault Led 2 Flash; Outdoor Unit Fault Led 3 Flash - Trane ACONT900AC43UA Service Manual

Outdoor unit fault LED's

Outdoor unit fault LED 1 Flash

Comfort Control:
- Err 90
Comfort Control:
- Err 91

Outdoor unit fault LED 2 flash

Comfort Control = No Error Code Displayed
User Interface = No Alert Displayed
Problem Description
• Defrost Fault A
- Low delta T or low heat pump capacity
Possible Causes/Solutions
• Inoperative compressor
• Shorted coil sensor
• Open ambient sensor

Outdoor unit fault LED 3 flash

Comfort Control = No Error Code Displayed
User Interface = No Alert Displayed
Problem Description
• Defrost Fault B and/or C
- Very high delta T
- Defrost terminated at least 10 times in a row on
maximum override time (15 minutes) instead of
temperature
Possible Causes/Solutions
• SOV stuck in heat mode
• Outdoor fan failure
• Open coil sensor
• Shorted ambient air sensor
User Interface:
- No Alert Displayed
Alert Code Response

Outdoor unit fault LED 4 flash

Comfort Control = No Error Code Displayed
User Interface = No Alert Displayed
Problem Description
• Defrost Fault A and (B and/or C)
- 60 or more A faults and one or more B faults
- 60 or more A faults and one or more C faults
Possible Causes/Solutions
• 60 or more defrost terminated with low delta T and at
least 10 defrost cycles terminated on time, not temp-
erature
• 60 or more defrosts terminated with low delta T and at
least 10 defrost cycles terminated with high delta T

Outdoor unit fault LED 7 Flash

Comfort Control:
- Err 79
- Wait

Outdoor unit fault LED 10 flash

Comfort Control = No Error Code Displayed
User Interface = No Alert Displayed
Problem Description
• (24volt mode only) 24 volts detected on Y2 without
voltage applied on Y1
Possible Causes/Solutions
• (24v mode only) Y1 and Y2 field wiring reversed
R - A 25