![background image](http://html1.mh-extra.com/html/carrier/fa4anf/fa4anf_service-manual_2561258029.webp)
Step 10—PCB Layout and Description
NOTE:
Layout of actual PCB is depicted in Fig. 24 and 25.
The PCB interfaces a variable-speed ICM2 with other system
components.
Power for system is supplied from a 230-vac, 60-Hz line. Class 2
voltage (24 vac nom.), used for thermostat connections, is derived
from transformer located in close proximity to PCB. The primary
and secondary of transformer are connected to PCB. The 24-vac
secondary circuit includes 5-amp automotive-type fuse in SEC2
circuit.
Connection to heater panel is made through 12-circuit connector
P1. Connections to thermostat are made at screw terminals.
Twenty-one pin terminals comprise field select taps for motor.
Fuse Data: 5-amp automotive-type ATC/ATO (tan)
32v
200 percent current opening time of 5 sec maximum
ELECTRICAL CONNECTIONS
Twenty-one 0.110-in pin terminals are used to provide program-
ming selections for operating modes of ICM2. The 6 selection
modes are listed below. For additional information, refer to Easy
Select Configuration Taps section.
AUX Heat Range—(Violet Wire)
AC/HP Size—(Blue Wire) Type—(Orange Wire)
AC/HP CFM Adjust—(Black Wire)
AC/HP Time Delay—(Grey Wire)
Continous Fan—(Yellow Wire)
Step 11—Sequence of Operation
CONTINUOUS FAN MODE
The thermostat closes circuit R to G. The G signal is sent directly
to ICM2.
COOLING MODE—SINGLE SPEED OR 2-SPEED HIGH
Thermostat closes circuits R to Y/Y2 and R to O (heat pump only)
for single speed. A circuit from R to Y1 is also required for
2-speed high.
COOLING MODE—TWO-SPEED LOW
Thermostat closes circuits R to Y1 and R to O (heat pump only).
The Y1 & O signals are sent to ICM2.
COOLING MODE—SUPER DEHUMIDIFICATION CALL
FROM THERMIDISTAT
Thermidistat closes circuits R to Y/Y2 and R to O (heat pump
only) for single speed. A circuit from R to Y1 is also required for
2-speed high. Thermidistat call for super dehumidification opens
circuit from R to G. The ICM adjusts airflow down to a lower
CFM for maximum dehumidification for a period of 10 minutes. If
this call continues, outdoor section and ICM shut off for 10
Fig. 23—FK4C, FV4A, and 40FKA ICM2.3 Motor
A98201
1
2
3
4
5
9
1 2 3 4 5 6 7 8
10 11 12 13 14 15 16
POWER CONNECTOR
CONTROL CONNECTOR
OPTIONAL SAFETY GROUND
DRAIN HOLE
DRAIN HOLE
OPTIONAL SAFETY GROUND
ENDSHIELD
DRAIN HOLE
CONTROL
POWER
29