12
d. Intelligent Staging of the electric heater elements to more
closely match heating load requirements and provide more
consistent heating air temperatures.
Procedure 9 — ACCESSORY INSTALLATION
A. Accessory Electric Heaters
Electric heaters may be installed with the FV4C Fan Coil per
instructions supplied with electric heater package. See unit rating
plate for factory--approved electric heater kits.
NOTE
: Units installed without electric heat should have a sheet
metal block--off plate covering the heater opening. This reduces air
leakage and formation of exterior condensation.
B. Auxiliary Terminals
The AUX and HUM terminals on the Easy Select Board are tied
directly to the G terminal, and provide a 24--vac signal whenever
the G terminal is energized. (See Fig. 17 and 18.) During Super
Dehumidify and SuperComfort / Perfect Heat modes, the G signal
is not present and the auxiliary terminals are not energized. If the
installation includes the use of these operating modes, do not use
these terminals to control accessories. See Electronic Air Cleaner
and Humidifier sections for further information.
C. Electronic Air Cleaner Connections
The AUX1 and AUX2 terminals are not always energized during
blower operation, as described above. When using an electronic air
cleaner with the FV4C Fan Coil, use Airflow Sensor Part No.
KEAAC0101AAA. The airflow sensor turns on electronic air
cleaner when the fan coil blower is operating.
D. Humidifier/Humidistat Connections
Easy Select Board terminals HUM1 and HUM2 are provided for
direct connection to the low--voltage control of a humidifier
through a standard humidistat. (See Fig. 19.) 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 when electric heaters are used as
primary heating source. When using a Thermidistat
t
Control,
Zone Perfect Plus or Comfort Zone II, the 24--vac signal may be
sourced directly from the Thermidistat HUM terminal. (See Fig. 9,
10, 11, and 12.)
HUMIDISTAT
TO HUMIDIFIER
HUMIDIFIER WIRING
HUM 1
(C)
HUM 2
(G)
24-VAC
A95317
Fig. 19 -- Humidifier Wiring
E. Dehumidify Capability with Standard Humidistat Connec-
tion
Latent capacities for systems using the FV4C Fan Coil are better
than average systems. If increased latent capacity is an application
requirement, the field wiring terminal block provides connection
terminals for use of a standard humidistat. The FV4C Fan Coil will
detect the humidistat contacts opening on increasing humidity and
reduce its airflow to approximately 80% of nominal cooling mode
airflow. This reduction will increase the system latent capacity until
the humidity falls to a level which causes the humidistat to close its
contacts. When the contacts close, the airflow will return to 100%
of the selected cooling airflow. To activate this mode, remove
Jumper J1 and wire in a standard humidistat. (See Fig. 20.)
EASY SELECT
BOARD TERMINAL
BLOCK
D
H
J1
R
HUMIDISTAT
REMOVE
JUMPER
A95316
Fig. 20 -- Humidistat Wiring for De--Humidify Mode
F. Dehumidify and Super Dehumidify Capabilities
This model fan coil is capable of responding to a signal from
indoor system control (Thermidistat, zoning control) to operate in
comfort control modes such as Super Dehumidify Mode. Consult
literature provided with indoor system control to determine if these
operating modes are available, and to see control set up
instructions. No special setup or wiring of fan coil is required.
Procedure 10 — FV4C FAN COIL SEQUENCE
OF OPERATION
The FV4C will supply airflow in a range which is more than twice
the range of a standard fan coil. It is designed to provide nominal
cooling capacities at a 50
_
F (10
_
C) evaporator temperature and the
required airflow which enables it to match with 4 air conditioner or
heat pump system sizes. Table 2 outlines the CFM range for the
different FV4C Fan Coil sizes.
A. Continuous Fan
S
Thermostat closes circuit R to G.
S
The blower runs at continuous fan airflow.
B. Cooling Mode -- Single speed
S
If indoor temperature is above temperature set point and
humidity is below humidity set point, thermostat closes circuits
R to G, R to Y/Y2 and R to O.
S
The fan coil delivers single speed cooling airflow.
C. Cooling Mode -- Dehumidification
S
If indoor temperature is above temperature set point and
humidity is above humidity set point, thermostat or
Thermidistat
t
closes circuits R to G, R to O, and R to Y/Y2,
and humidistat or Thermidistat opens R to DH.
S
The fan coil delivers airflow which is approximately 80% of the
nominal cooling airflow to increase the latent capacity of the
system.
D. Cooling Mode -- Super Dehumidify Operation (See Fig. 22
for Quick Reference Guide)
NOTE
: The indoor control used, such as Thermidistat, must be
capable of providing Super Dehumidify operation mode and
control must be configured as outlined in its installation
instructions. Consult indoor control literature to determine if
control is capable of providing Super Dehumidify inputs and for
configuration instructions.
If the indoor temperature is below the temperature set point and the
humidity is above the humidity set point, the Thermidistat closes
circuit R to O, opens circuits R to DH and R to G, and cycles
circuit R to Y/Y2 (for single speed system R to Y1, or R to Y1 and
Y/Y2 for 2--speed system).
The ECM motor reads the G signal to the fan coil while the heat
pump is operating, (circuit R to Y/Y2 for single speed system, R to
Y1 or R to Y1 and Y/Y2 for 2--speed system), closed (24 vac). If
circuit R to G is closed (24 vac), the motor will deliver airflow at
FV4
C
