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.
11
A95316
Fig. 7 – Humidistat Wiring for De-Humidify Mode
FCM4
Model FCM4 fan coil is designed to be installed with the Observer™
communicating wall control. The FCM4 fan coil will provide airflow at
a rate commanded by the Observer wall control. The nominal
airflow/ton rate is 350 CFM/ton. The Observer wall control will modify
the commanded airflow under certain operating modes. Refer to the
Observer wall control literature for further system control details. This
fan coil will not respond to commands from a common thermostat
except under certain emergency situations explained in this document.
ELECTRONICALLY COMPUTED MOTOR ECM 3.0
An ECM 3.0 is fed high voltage AC power through the 5-pin connector.
The AC power is then internally rectified to DC by a diode module.
After rectification, DC signal is electronically communicated and fed in
sequential order to 3 stator windings. The frequency of these
communication pulses determines motor speed. The rotor is permanently
magnetized.
ECM 3.0 CONTROL POWER
The ECM 3.0 control power is supplied from R circuit through printed
circuit runs to motor control connector Plug #1, Pin #1, through motor
control harness to motor. The C side of low-voltage control power circuit
is connected by printed circuit runs to motor connector Plug #1, Pin #2
then through motor control harness to motor. A digital signal is sent from
Plug #1, Pins #3 and #4 to communicate with the motor including all
airflow requirements.
LOW-VOLTAGE CIRCUIT FUSING AND REFERENCE
The low-voltage circuit is fused by a board-mounted 5-amp automotive
type fuse placed in series with transformer SEC2 and R circuit. The C
circuit of transformer is referenced to chassis ground through a printed
circuit run at SEC1 connected to metal standoff.
NOTE: The PCB must be mounted with two screws and motor ground
lead secured to blower housing or erratic motor operation can result.
TRANSFORMER, MOTOR, AND ELECTRIC HEATER POWER
CONNECTION
Transformer high voltage supplied from electric heater package or high
voltage leads through 12-pin heater connector plug/recp2. The ECM 3.0
power connections are made at the transformer primary terminals. The
transformer secondary connections are made at SEC1 and SEC2
connectors.
TROUBLESHOOTING
NOTE: Always check high and low voltage supply to the fan coil
components. Check the integrity of the plug receptacle connections and
fan coil wiring harness prior to assuming a component failure.
LED Description:
LEDs built into fan coil control provide installer or service person
information concerning operation and/or fault condition of the fan coil
control and ECM motor. This information is also available at the
Observer wall control in text with basic troubleshooting instructions.
Careful use of information displayed will reduce the need for extensive
manual troubleshooting.
The amber LED located at bottom center of control adjacent to motor
harness plug is Motor Status LED, and it is labeled MOTOR. A second
amber LED, located in upper right center of control adjacent to System
Communications connector (DX+, DX-, C, R), is the System Status
LED, and it is labeled STATUS. The green LED labeled COMM is also
located adjacent to System Communications connector, below STATUS
LED, and is used as an indicator of system communications status.
Status Codes will be displayed on the STATUS LED using the following
protocol:
1. The number of short flashes indicates first digit of code.
2. The number of long flashes indicates second digit of code.
3. A short flash is 0.25 seconds on. A long flash is one second on.
4. The time between flashes is 0.25 seconds.
5. The time between last short flash and first long flash is 1 second.
6. The LED will be off for 2.5 seconds before repeating code.
Fan Coil Control Start-Up and System Communications
Troubleshooting:
On power up, green COMM LED will be turned off until successful
system communications are established (this should happen within 10
seconds). Once communications with Observer wall control are
successful, COMM LED will be lit and held on. At the same time, amber
STATUS LED will be lit and held continuously on until a request for
operating mode is received. The STATUS LED will be on any time fan
coil is in idle mode.
If, at any time, communications are not successful for a period exceeding
two minutes, fan coil control will only allow emergency heating or
cooling operation using a common thermostat, a non-communicating
outdoor unit and the R, C, Y, O, W outdoor unit terminal strip
Table 5 – TFVM4 Motor Control Test Values (with 16-pin Connector at Motor Unplugged)
Terminals
Jumpered
Volt Meter on 16-pin Harness Plug
Volt Meter on 12-pin
Easy Select Board Plug
Voltage
+ - + -
R to W1
Pin
#2 Pin #1 Pin #7 Pin #9
24VAC
R to W2
Pin #13 Pin #1 Pin #4 Pin #9
24VAC
R to Y1
Pin
#6 Pin #1 Pin #3 Pin #9
(-)12VDC
R to Y/Y2
Pin
#14 Pin #1 Pin #2 Pin #9
(-)12VDC
R to G (LO)
Pin #15 Pin #1 Pin #3 Pin #9
0VAC
R to G (MED)
Pin #6 Pin #1 Pin #3 Pin #9
(-)12VDC
R to G (HI)
Pin
#14 Pin #1 Pin #2 Pin #9
(-)12VDC
EASY SELECT
BOARD TERMINAL
BLOCK
D
H
J1
R
HUMIDISTAT
REMOVE
JUMPER
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