Service Manual

SERVICE AND MAINTENANCE FAN COILS
14 496 08 8001 02
Specifications subject to change without notice.
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 Observer wall control.
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. 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 Observer wall control and
check heater stage 24−Vac 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.
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.
ECM Motor Troubleshooting.
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), Observer wall
control 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 Observer wall control in a fully
communicating system.
1. If outdoor unit size is invalid, Status Code 27 will be
displayed on STATUS LED.
2. If model size data is missing (as is the case when a
replacement outdoor control is installed), Observer wall
control 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 Observer wall
control has established communications with outdoor
unit or select proper size from valid size list provided at
Observer wall control.
4. Check motor and motor control module following the
instructions in Section C. ECM Motor Troubleshooting.
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, Observer
wall control will prompt installer 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.
4. Make sure heater size installed is an approved size for
outdoor unit and fan coil sizes installed.
NOTE: Fan coil control will not operate electric heater until
this Status Code is resolved. If the heater size is set through
the Observer wall control, the heater will be operated as a
single stage heater. If staging is desired, the IDR value must
be read in by the fan coil control.