Carrier FB Series Service And Maintenance Instructions page 16

FB, FE, FF1E, FFM, FG, FH, FJ, FMA, FT, FV, FX, FY, FZ, F54, PF: Service and Maintenance Instructions
Using 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 fan coil 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 Troubleshooting.
Fan Coil Troubleshooting
Fan coil 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:
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 24VAC
signal on Electric Heater stage 1 and stage 2 outputs.
If fan coil control detects a 24VAC signal on either heater stage output
and it is not supplying signal, Status Code 37 will be displayed on
STATUS LED. Fan coil 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 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 36 for more information.
STATUS CODE 44, MOTOR COMMUNICATION FAULT:
The MOTOR LED is connected to the blower motor communication line
and works with the fan coil control microprocessor and STATUS LED to
provide fan coil 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.
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 control will display Status Code 44 on
STATUS LED and continue to try to communicate with the motor. If
motor acknowledges 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.
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
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 12VDC 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
Shorted or mis-wiring of the low voltage motor harness wiring will not
cause damage to fan coil control or to motor control module.
If the MOTOR LED is off, STATUS LED is indicating a Status Code 44
and motor is running:
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, fan coil control shall poll motor for its size data and
check fan coil size data stored in fan coil control memory.
1. If motor size is incorrect for fan coil size or fan coil 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 is installed), system User Interface 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 27, INVALID OUTDOOR UNIT SIZE:
On initial power-up, fan coil control will write into memory outdoor unit
size as provided by User Interface in a fully communicating system.
1. If outdoor unit size is invalid, Status Code 27 will be displayed on
STATUS LED.
2. User Interface will prompt the installer to choose size from a list of
valid sizes for application with fan coil.
3. Check communications wiring to be sure User Interface has
established communications with outdoor unit or select proper size
from valid size list provided at User Interface.
4. Check motor and motor control module following the instructions
in (ECM Motor Troubleshooting on
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 combination of indoor and
outdoor components installed. Fan coil control will read IDR value
connected to Pins 5 and 8 of heater harness connector. If no resistor is
found, system User Interface will prompt installer to verify that no
heater is installed.
Verifying that this is correct will establish that fan coil 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 fan coil and outdoor 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 5 and 8 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
heater header and check for a resistance value greater than 5000
ohms.
3. Check for proper wiring of resistor assembly.
16
(ECM Motor Troubleshooting on
p15).
p15).