Carrier FA4ANF Service Manual Download Page 22

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HEAT PUMP HEATING MODE—TWO-SPEED LOW

Thermostat closes R to Y1. The Y1 signal is sent directly to ICM2.

HEAT PUMP HEATING WITH AUXILIARY ELECTRIC
HEAT

Thermostat closes circuits R to Y/Y2 and/or R to Y1 with R to W2,
W3, or E (and R to O in the case of defrost).

See previously described modes for circuit paths.

In the event that electric heating is called for by thermostat while
heat pump is also operating in either heating or defrost mode,
electric heating signal will appear at motor connector pin 1 as
described previously. If necessary, the motor will modify its
airflow output to provide an airflow which is defined as safe for
operation of electric heater.

CFM SELECT CONFIGURATION TAPS

The CFM Select taps are used by installer to configure system. The
ICM2 is capable of discerning wave shapes on some of its inputs
and uses this capability to modify its operation to a pre-
programmed table of airflows and can be modified in response to
other inputs such as the need for de-humidification.

ICM2 CONTROL POWER

The ICM2 control power is supplied from R circuit through
printed-circuit runs to motor control connector pin 6, through
motor control harness to motor. The C side of low-voltage control
power circuit is connected by printed-circuit runs to motor
connector pins 4 and 5, then through motor control harness to
motor.

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 marked GROUND SCREW REQUIRED.

NOTE:

A ground screw must be in place or erratic motor

operation can result.

TRANSFORMER, MOTOR, AND ELECTRIC HEATER
POWER CONNECTIONS

The high-voltage (230-vac) power input to board is provided
through electric heater connector pins 7 and 9. The high voltage is
then connected through printed-circuit runs to motor power con-
nections M1 and M2 and transformer power connections T1 and
T3. Transformer connection T2 is a dummy terminal used for
unused primary power lead. The transformer secondary connec-
tions are made at SEC1 and SEC2 connectors.

Step 4—Easy Select Configuration Taps

The Easy Select taps are used by installer to configure system. The
ICM2 uses selected taps to modify its operation to a pre-
programmed table of airflows. Airflows are based on system size
or mode of operation and those airflows are modified in response
to other inputs such as the need for de-humidification.
(See Fig. 16.)

The FK4B Fan Coil must be configured to operate properly with
system components with which it is installed. To successfully
configure a basic system (see information printed on circuit board
located next to select pins), move the 5 select wires to pins which
match components used.

Fig. 16—Easy Select Board

A94076

EASY SELECT

GROUND

SCREW

REQUIRED

Y/Y2

CES0130007–00

D8 D7 D5

HEATER

240

VAC