Carrier 50CR - Manual (Page 19)

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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.
Unit 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.
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 unit control.
If all checks are normal, unit control 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.
Shorted or mis--wiring of the low voltage motor harness wiring will
not cause damage to unit control or to motor control module.
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 unit control. If motor
continues to run, unit control is good and control module on
motor may need replacement.
STATUS CODE 25, INVALID MOTOR / MODEL SELECTION
On initial start--up, unit control shall poll motor for its size data and
check unit size data stored in unit 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 control board 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. Unit control will not
respond to operation requests until this fault condition is
resolved.
STATUS CODE 26, INVALID HEATER SIZE
On initial power--up, unit 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. Unit control will read IDR value
connected to pins 1 and 2 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 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 unit
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: Unit control will not operate electric heater until this Status
Code is resolved. If the heater size is set through the User Interface,
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.
STATUS CODE 36, HEATER OUTPUT NOT SENSED WHEN
ENERGIZED
Unit control is provided with circuitry to detect presence of a 24--vac
signal on electric heater stage 1 and stage 2 outputs.
If unit control energizes either heater stage and does not detect the
24--vac signal on output, Status Code 36 will be displayed on the
STATUS LED, unit control will continue to energize heater
output(s) and adjust blower operation to a safe airflow level for
energized electric heat stage(s).
To find the fault:
1. Check for 24--vac on heater stage outputs. Unit control or
sensing circuit may be bad.
NOTE: It may be useful as an electric heater troubleshooting
procedure to disconnect the system communications to force Status
Code 16 enabling of emergency heat mode. It is difficult to know
which heater output is energized or not energized in normal
operation. When unit is operated in emergency heat mode using
electric heaters, both outputs are energized and de--engergized
together. Terminal strip inputs to control can then be connected R to
W to turn on both electric heat outputs. Heater output sensing
circuits can then be checked to resolve Status Code 36 or 37
problems.
STATUS CODE 41, BLOWER MOTOR FAULT
If MOTOR LED is lit and flashing and motor does not run:
1. Check STATUS LED. If STATUS LED is indicating Status
Code 41, motor control has detected that the motor will not
come up to speed within 30 seconds of being commanded to
run or that the motor has been slowed to below 250 rpm for
more than 10 seconds after coming up to speed. Motor
wiring harness and unit control are operating properly, do
not replace.
2. Check to be sure that the blower wheel is not rubbing the
housing.
3. Check motor to be sure that the motor shaft is not seized
(motor control module must be removed and electronics
disconnected from windings to perform this check
properly).
4. Check motor windings section following instructions in
Section C, ECM Motor Troubleshooting.
If all these checks are normal, the motor control module may need
replacement.
STATUS CODE 16, SYSTEM COMMUNICATION FAULT
If, at any time, system communications are not successful for a
period exceeding 2 minutes, the unit control will only allow
emergency heating or cooling operation using a common
thermostat, and the R, C, Y, O, W terminal strip connections and will
display Status code 16 on the amber STATUS LED (see section E,
Emergency Heating and Cooling Modes). No further unit
troubleshooting information will be available at the User Interface
until communications are re--established.
50C
R