Communicating Systems Troubleshooting Checklist - Trane ACONT900AC43UA Service Manual

Air Handler
• After 1 second energize stage 2 heat relay
• After 1 more second energize stage 3 heat relay
• After 5 seconds de-energize blower interlock, stage
1, 2 & 3 heat relays
(User Interface displays UNIT TEST – EXIT)
• Displayed for three seconds
Note: Airflow is default or programmed selections

Communicating Systems Troubleshooting Checklist

AH - A 8
Notes:
† If Air Handler processor is re-
set or fuse is open, COMM Alert
cannot be reported; if the pro-
cessor is reset the User Inter-
face will not be updated.
* Alert flash code will not be
implemented for initial release.
** COMM communication errors
may also be flashed on Fault
LED.
‡ LitePort™ transmissions will be
allowed during ON flash codes.
+ Fuse alert notification level
would show on Comfort Control,
but when Fuse is open the
COMM bus has no power.
A/H Air Handler
TS Troubleshooting
Procedure Number
PM Personality Module
ID Indoor
SYS System
BLW Indoor Blower Motor
COMM Communication
CRC Circuit
HT Heater
LK Interlock
INTLK Interlock
EXT External
SW Switch
MTR Motor
CAP Compressor Capacity
DAS Discharge Air Sensor
RAS Return Air Sensor