Carrier Infinity 50XT-A Installation Instructions Manual page 16

MOTOR TURNS SLOWLY
1. Low static pressure loading of blower while access panel is
removed will cause blower to run slowly. Particularly at low
airflow requests. This is normal, do not assume a fault
exists.
2. Recheck airflow and system static pressure using UI service
screens with access panel in place.
NOTE: Blower motor faults will not cause a lockout of blower
operation. The fan coil control will attempt to run the blower motor
as long as UI maintains a demand for airflow. The control will not
operate electric heaters while a fault condition exists. The control
communicates with the motor at least once every five seconds,
even when the motor is idle. If, during operation, the control does
not communicate with the motor for more than 25 seconds, the
motor will shut itself down and wait for communications to be
reestablished.
D. Using Fan Coil Control Motor LED in Troubleshooting
The MOTOR LED is connected to the blower motor
communication line and works with the fan coil control
microprocessor and the STATUS LED to provide unit operation
and troubleshooting information. When the 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.
If the MOTOR LED is lit, flashing, and the motor is running, or if
the MOTOR LED is off and the motor is stopped, operation is
normal and no motor fault exists.
If the MOTOR LED is lit, flashing, and the motor does not run, or
if the MOTOR LED is off and the motor is running, check the
STATUS LED for the Status Code. Refer to the troubleshooting
instructions for the indicated Status Code in Section E, Fan Coil
Control Troubleshooting.
E. Fan Coil Control Troubleshooting
Fan coil control 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 UI.
STATUS CODE 45, CONTROL BOARD TEST FAULT
Fan coil control 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:
Fan coil control is provided with circuitry to detect presence of a
24- -vac signal on electric heater stage 1 and stage 2 outputs.
If fan coil control detects a 24- -vac signal on either heater stage
output and it is not supplying signal, Status Code 37 will be
displayed on STATUS LED. Control 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 UI and check heater stage
24- -vac outputs.
2. Disconnect electric heater at power and check heater wiring
for faults. See Status Code 36 for more information.
STATUS CODE 44, MOTOR COMMUNICATION FAULT
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.
Fan coil control is constantly communicating with the motor, even
when the motor and MOTOR LED are off. If motor does not
acknowledge receipt of communications, the fan coil control will
display Status Code 44 on STATUS LED and continue to try to
communicate with the motor.
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 fan coil control.
If all checks are normal, fan coil control is good and control
module on motor may need replacement. Check motor and Motor
Control Module following the instructions in Section C, Indoor
Fan Motor Troubleshooting.
If the MOTOR LED is off, STATUS LED is indicating a Status
Code 44 and motor is running:
1. Disconnect the motor harness at the fan coil control. If
motor continues to run, fan coil control is good and control
module on motor may need replacement.
STATUS CODE 25, INVALID MOTOR / MODEL SELECTION
On initial start- -up, the fan coil control shall poll motor for its size
data and check unit size data stored in the control memory.
1. If motor size is incorrect for unit size or size data is invalid,
Status Code 25 will be displayed on STATUS LED.
2. If model size data is missing (as is the case when a
replacement fan coil control board is installed), system UI
will prompt installer to enter correct model size from a list
of valid sizes.
3. If motor size is incorrect for model size, motor must be
replaced with proper size motor. Fan coil control will not
respond to operation requests until this fault condition is
resolved.
STATUS CODE 26, INVALID HEATER SIZE
On initial power- -up, fan coil control will write into memory
electric heater size as read from heater if heater is provided with
Identifier Resistor (IDR). Heater size must be valid for the installed
unit. Fan coil control will read IDR value connected to pins 1 and 2
of heater harness connector. If no resistor is found, system UI will
prompt installer to verify that no heater is installed. Verifying that
this is correct will establish that the unit is operating without an
electric heater accessory. Upon choosing negative option, installer
will be prompted to select heater size installed from a list of valid
heater sizes for unit size installed.
If heater ID resistor value read is invalid, Status Code 26 will be
displayed on STATUS LED.
If heater installed is equipped with a resistor connected to pins 1
and 2 of heater harness connector and status code 26 is displayed
on STATUS LED:
1. Check wiring harness connections to be sure connections
are secure.
2. If symptoms persist, disconnect wiring harness at fan coil
control board and check for a resistance value greater than
5000 ohms.
3. Check for proper wiring of resistor assembly.
4. Make sure heater size installed is an approved size for unit
and size installed.
NOTE: Fan coil control will not operate electric heater until this
Status Code is resolved. If the heater size is set through the UI, the
heater will be operated as a single stage heater. If staging is desired,
the IDR value must be read in by the unit control.
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If motor acknowledges