3. A 30 sec on (delay with no airflow)/ 90 sec off (delay at 100 percent airflow) profile is used when it is desirable to allow system coils time
to heat-up/cool-down in conjunction with the airflow. (This profile will minimize cold blow in heat pump operation and could enhance
system efficiency.)
4. ENH, enhanced selection, provides a 30 sec on (delay with no airflow)/ 180 sec off (delay at half airflow) add comfort and efficiency results.
F. CONTINUOUS FAN — Select desired fan speed when thermostat is set on continuous fan
1. LO speed — factory setting, 50 percent cooling mode airflow
2. MED speed — move connector to MED, 65 percent cooling mode airflow.
3. HI speed — move connector of HI, 100 percent cooling mode airflow. (See Fig. 16, F as indicated.)
G. LOW-VOLTAGE CIRCUIT FUSING AND REFERENCE
The low-voltage circuit is fused by a board-mounted 5-amp automotive fuse placed in series with the transformer SEC2 and the R circuit. The C
circuit of the transformer is referenced to chassis ground through a printed circuit run at SEC1 connected to metal standoff marked with ground
symbol.
PROCEDURE 10—ACCESSORY INSTALLATION
A. Accessory Electric Heaters
Electric heaters may be installed with the FK4C Fan Coil per instructions supplied with the electric heater package.
NOTE: It is not necessary to cover the opening for accessory heaters. The unit will perform properly without this opening covered.
B. Electronic Air Cleaner Connections
Because the ICM2 blower motor used in the FK4C Fan Coil is controlled by low-voltage signals, a switched 230-vac electronic air cleaner power
signal is not available. This signal is replaced by a 24-vac signal which is provided at PCB terminals AUX1 and AUX 2 (See Fig. 16 and 17.)
This signal is present whenever the G thermostat signal is present (heat pump heating, cooling and continuous blower modes). When the FK4C
Fan Coil is installed with an electronic air cleaner, use EAC relay kit Part No. KFAIR0201ACR or a field supplied 24-vac relay.
The EAC relay kit consist of a 24-vac relay which mounts directly on the PCB bracket inside the fan coil using factory punched screw holes, 2
mounting screws, 2 pre-terminated wires for connection of relay coil to AUX1 and AUX2 terminals, 2 No. 16 AWG stripped leads for connection
of relay contacts for control of power to the EAC, wire nuts, and wiring instructions. (See Fig. 18.)
If EAC relay is field supplied, use field supplied wiring, terminations and wire per the EAC wiring schematic. (See Fig. 19.)
NOTE: If the FK4C is installed with an air conditioner and electric heat is the primary heating device, a thermostat which turns on the G output
with a call for heat is required for air cleaning or humidification during heating mode. A corporate thermostat set to "fan on with W option" is
recommended.
C. Humidifier/Humidistat Connections
Terminals HUM1 and HUM2 are provided for direct connection to the low-voltage control of a humidifier through a standard humidistat. (See
Fig. 17.) These terminals are energized with 24vac when G thermostat signal is present. (See Fig. 20.) Alternately, the 24-vac signal may be
sourced from the W and C terminal block connections.
Fig. 16—Detail of FK4C Printed-Circuit Board
A95275
EASY SELECT
D
H
R
W
1
W
2
Y
1
Y/ Y
2
G
O
C
HEATER/MOTOR
CEBD430226-01B CESS430226-01B
AUX HEAT KW/CFM
0-30
1075
SEC1 SEC2
J1
J2
AC/HP SIZE
036 030 024 018
AC
HP-COMFORT
HP-EFF
NOM HI
ENH
LO
SYSTEM TYPE
AC/HP CFM ADJUST
ON/OFF DELAY
CONTINUOUS FAN
MED HI YELLO
AUX1 HUM1
AUX2
24VAC
GRY
HUM2
YEL
WHT
BLK
ORN
BLU
VIO
0-20
875
0-10
725
0
90
30
90
0
0
0-5
625
TM
LOW VOLTAGE TERMINAL BLOCK
PRINTED CIRCUIT BOARD
MOLEX 12-PIN CONNECTOR
A
B
C
D
E
F
—13—
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