Trane ACONT900AC43UA - Ground fault; Communication busy fault

R - A 21
Alert Code Response
Communication busy fault
Comfort Control = No Error Code Displayed
User Interface = BLW COMM CRC
Air Handler Fault LED = 3 Flash
or
Furnace Fault LED = 10 Flash
Problem Description
• Blower motor unrecognized response
- Communication with blower motor cannot be
established
Possible Causes/Solutions
• Reboot line voltage to furnace and check to see if fault
clears
- If error does not clear contact your local field rep for
additional support
Communication busy fault
Comfort Control = No Error Code Displayed
User Interface = IND COMM CRC
Furnace Fault LED = 10 Flash
Problem Description
• Inducer motor unrecognized response
- Communication with draft inducer motor cannot
be established
Possible Causes/Solutions
• Reboot line voltage to furnace and check to see if fault
clears
- If error does not clear contact your local field rep for
additional support
Communication busy fault
Comfort Control = No Error Code Displayed
User Interface = SYS COMM CRC
Air Handler Fault LED = 3 Flash
or
Furnace Fault LED = 10 Flash
Problem Description
• Excessive communication errors
- Comfort control is continually attempting to
communicate with no idle detected (bus busy)
Possible Causes/Solutions
• Faulty field control wiring to comfort control
• Telephone Access Module (TAM) out of sequence
- Disconnect TAM and recycle power, if error clears,
replace the TAM
- If error does not clear contact your local field rep for
additional support
Ground fault
Comfort Control = No Error Code Displayed
User Interface = GND FAULT
Furnace Fault LED = 6 Flash
Problem Description
• Proper earth ground not detected (more than 8v line
neutral to ground)
- Due to software limitations, reversed polarity faults
(POLARITY ERR) and grounding faults (GND FAULT)
will occur simultaneously
Possible Causes/Solutions
• Furnace ground not connected to earth ground
• Chassis grounds not connected or poor connection
• Incoming power supply not grounded to main
electrical panel
- Also see POLARITY ERR for additional causes