Carrier FCM4 - Fvm4

FCM4, FEV, FEM4, FJM, FMA4, FSA4, FSM4, FSU4, FVM4, FXM4, REM4, WAH, WAM, WAP, WAX, WBHL: Service and Maintenance Instructions
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
5
aluminum end plate of the motor. This resistance should be greater
than 100,000 ohms.
3. Check the motor phase-to-phase resistance between each of the
leads in the three-pin motor connector. The lead-to-lead resistance
across any two leads should be less than 20 ohms. Each lead-to-lead
resistance should be the same within ± 10 percent.
IMPORTANT: If any motor fails any of the three tests, do not install a
new control module. The new control can fail if placed on a defective
motor.
The prior fan coil models with multi-speed ECM blower motors used a
printed circuit board, similar to the PSC models. The current fan coils do
not use the printed circuit board and rely on the motor control
programming to provide the off-delay timing.
Another design aspect of the control board was to provide a resistor in
the “G” circuit in case a power stealing thermostat was used. This
resistor is no part of the wiring harness, as shown on wiring diagram.
The resistor is a 2-Watt, 1500-ohm resistor.
If the resistor has failed open, a likely cause is due to the power stealing
thermostat. Connecting C (common) may resolve the issue. Having an
open resistor should not affect the operation of the motor.
Fan Speed Selection
The fan speed selection is done at the motor connector. Units with or
without electric heaters require a minimum CFM. Refer to the unit
wiring label to ensure that the fan speed selected is not lower than the
minimum fan speed indicated.
To change motor speeds disconnect the BLUE fan lead from motor
connector terminal No. 2 (factory default position) and move to desired
speed-tap; 1, 2, 3, or 5.
Speed-taps 1, 2, and 3 have a 90-second blower off time delay
pre-programmed into the motor. Speed-tap 4 is used for electric heat
only (with 0 second blower time delay) and the WHITE wire should
remain on tap 4. Speed-tap 5 is used for high static applications, but has
a 0-second blower time delay pre-programmed into the motor. See
Airflow Performance tables for actual CFM. Also, see Fig. 4 for motor
speed selection location.
NOTE: In low static applications, lower motor speed tap should be used
to reduce possibility of water being blown off coil.
† electric heat airflow is same CFM as Tap 3, except 0 sec off delay
‡ high static applications, see airflow tables for max airflow
A11048
Fig. 3 – Motor Speed Selection
A13028
Fig. 4 – FVM4 motor/ECM 5.0 Motor
FVM4
Constant Air Flow
Unlike fan coils using induction motors where static pressure affects
airflow, these fan coils are constant airflow units. The blower delivers
requested airflow regardless of static pressure. Consult fan coil
Specification Sheet for static pressure limits. The ECM 5.0 is
pre-programmed and contains airflow tables for all modes of operation.
Blower characteristics (requested airflow, torque, and speed) are known
Table 1 – Speed Selection Taps
Tap 1 Low 90 sec off delay
Tap 2 Medium 90 sec off delay
Tap 3 High 90 sec off delay
Tap 4 Electric heat † 0 sec off delay
Tap 5 Max ‡ 0 sec off delay
1 2 3 4 5
Speed Taps may be located on motor,
or on plug close to motor.
CLGN
1 2 3 4 5
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