Ecm Board Troubleshooting; Ecm Blower Start- -Up & Troubleshooting; Emergency Heating & Cooling Modes; Ecm Board Start- -Up - Carrier GC Series Installation Instructions Manual

ECM BOARD TROUBLESHOOTING

LED Description:
LEDs built into ECM board provide installer or service person
information concerning operation and/or fault condition of the
ECM board and ECM motor. This information is also available at
system user interface in text with basic troubleshooting
instructions. Careful use of information displayed will reduce the
need for extensive manual troubleshooting.
The amber LED located at bottom center of control adjacent to
motor harness plug is motor status LED and it is labeled MOTOR.
A second amber LED located in upper right center of control
adjacent to System Communications connector (A,B,C,D) is the
System Status LED and it is labeled STATUS. The green LED
labeled COMM is also
Communications connector, below STATUS LED, and is used as
an indicator of system communications status. Status Codes will be
displayed on the STATUS LED using the following protocol:
1. The number of short flashes indicates first digit of code.
2. The number of long flashes indicates second digit of code.
3. A short flash is 0.25 seconds on. A long flash is 1 second
on.
4. The time between flashes is 0.25 seconds.
5. The time between last short flash and first long flash is 1
second.
6. The LED will be off for 2.5 seconds before repeating code.
ECM Blower Start- -Up and Troubleshooting
NOTE: Always check high and low voltage supply to the GC
components. Check the integrity of the plug receptacle connections
and blower wiring harness prior to assuming a component failure.
Emergency Heating and Cooling Modes
ECM board can provide emergency heating or cooling using a
common heat/cool thermostat in the event that there are no system
communications, fault is in User Interface and no replacement is
immediately available.
To activate these modes, the thermostat and outdoor unit must be
wired as a common heating/cooling system to ECM board
RGWYOC terminals.
NOTE: These emergency modes do not provide the level of
comfort and efficiency expected by the consumer and should only
be activated when User Interface cannot be replaced immediately.
ECM Board Start- -Up and System Communica-
tions Troubleshooting
On power up, green COMM LED will be turned off until
successful system communications are established (this should
happen within 10 seconds). Once communications with user
interface are successful, COMM LED will be lit and held on. At
the same time, amber STATUS LED will be lit and held
continuously on until a request for operating mode is received. The
STATUS LED will be on any time blower is in idle mode. If, at
any time, communications are not successful for a period
exceeding 2 minutes, ECM board will display Status Code 16,
System Communication Fault, on amber STATUS LED. No
further blower troubleshooting information will be available at user
interface until communications are re- -established.
If COMM LED does not light within proper time period and Status
Code is not displayed:
1. Check system transformer high and low voltage to be sure
the system is powered.
2. Check fuse on ECM board to be sure it is not blown. If fuse
is open, check system wiring before replacing it to be sure a
short does not cause a failure of replacement fuse.
If COMM LED does not light within proper time period and Status
Code is displayed:
located adjacent to System
Check system wiring to be sure user interface is powered and
connections are made A to A, B to B, etc. and wiring is not
shorted. Mis- -wiring or shorting of the ABCD communications
wiring will not allow successful communications.
NOTE: Shorting or mis- -wiring low voltage system wiring will
not cause damage to ECM board or user interface but may cause
low voltage fuse to open.

ECM Board Status (Fault) Codes

Blower faults indicated by flashing codes on the amber system
STATUS LED can be resolved using troubleshooting information
provided below. Codes are listed in order of their priority, highest
to lowest. Though multiple faults can exist at any time, only the
highest priority code will be displayed on STATUS LED. Clearing
the indicated fault when multiple faults exist will cause the next
highest priority Status Code to be flashed. All existing faults, as
well as a fault history, can be viewed at user interface.
STATUS CODE 45, CONTROL BOARD TEST FAULT:
ECM board has failed internal start- -up tests and must be replaced.
No other service procedure will correct.
STATUS CODE 37, HEATER OUTPUT SENSED "ON"
WHEN NOT ENERGIZED:
ECM board is provided with circuitry to detect presence of a
24VAC signal on Electric Heater stage 1 and stage 2 outputs. If
ECM board detects a 24VAC signal on either heater stage output
and it is not supplying signal, Status Code 37 will be displayed on
STATUS LED. ECM board will turn off output and command
blower motor to supply an airflow determined to be safe for current
operation mode with electric heaters energized.
To find the fault:
1. Stop all system operations at User Interface and check
heater stage 24VAC outputs.
2. Disconnect electric heater at plug/receptacle 2 and check
heater wiring for faults. See Status Code 37 for more infor-
mation.
STATUS CODE 44, MOTOR COMMUNICATION FAULT:
The MOTOR LED is connected to the blower motor
communication line and
microprocessor and STATUS LED to provide blower operation
and troubleshooting information. When motor is commanded to
operate, the MOTOR LED will be turned on and will flash each
time instructions are sent to the motor.
When the motor is commanded to stop, the MOTOR LED will be
turned off. The MOTOR LED will not flash to indicate
communications when it is turned off.
ECM board is constantly communicating with the motor, even
when the motor and MOTOR LED are off. If motor does not
acknowledge receipt of communications, the control will display
Status Code 44 on STATUS LED and continue to try to
communicate with the
communication, Status Code will be cleared.
If MOTOR LED is lit and flashing and motor does not run:
1. Check the STATUS LED. If STATUS LED is indicating a
Status 44 code, check the motor wiring harness for proper
connection to control and motor receptacles.
2. Check motor wiring harness to be sure all wiring complies
with wiring diagram description, makes a complete circuit
from connector to connector and is not shorted.
3. Check 12 Vdc low voltage supply to motor at pins 1 (+) and
2 (- -) of motor header connection to ECM board.
If all checks are normal, ECM board is good and Control Module
on motor may need replacement. Check motor and Motor Control
Module following the instructions in Section C. ECM Motor
Troubleshooting.
36
works with the ECM
motor. If motor acknowledges
board