iComfort
Wi‐Fi
®
7-Day Programmable Communicating Thermostat
17
HOW DEHUMIDIFICATION MODE WORK — NO EXTERNAL
DEHUMIDIFICATION DEVICE
NOTE -
OFF, MEDIUM
and
HIGH
dehumidification modes are also a function of
the HVAC system with NO external dehumidification devices installed.
In
OFF
mode, dehumidification if off.
In
MEDIUM
mode, dehumidification occurs if these conditions are met and
signals are present at specific terminals:
dehumidification has been enabled on installer settings, and
the unit is in COOL mode, and
dehumidification demand exists (RH above setpoint), and
cooling demand exists (Y1 energized).
In
HIGH
mode, dehumidification occurs if all BASIC conditions are true, except
cooling demand may or may not be present. Also note that:
Maximum overcool from cooling setpoint is 2ºF.
Deadband
temperature is limited to a minimum of 5ºF (instead of 3ºF
in
DRY
or
MODERATE
modes) because of 2ºF overcooling.
AUXILIARY DEHUMIDIFIER — COMMUNICATING OR
NON-COMMUNICATING OUTDOOR UNITS
Control State
Conditions
Auxiliary dehumidification is
controlled by iComfort
®
thermostat with or without zoning.
System must be in cooling mode
and have a call for dehumidification
from the iComfort
®
thermostat. This
will start the auxiliary dehumidifier.
A separate wire from auxiliary
dehumidifier will need to be run to
G
terminal on indoor unit control to
start the blower.
Auxiliary dehumidification is con
trolled by dehumidification con
trol with or without zoning
Needs a dehumidification demand from
the stand-alone dehumidification thermo
stat and a separate wire run to G terminal
on indoor unit to start the blower.
Zoning Control Settings
NOTE - Skip if no zoning control device is installed.
A. Heat/Cool Changeover
The following is an example of how the system operates during a heating /
cooling changeover.
When the system is satisfying a call from zone 1 for heating and receives a
call for cooling from zone 2, the following will occur:
Then system will continue to fulfill the demand from zone 1 until
satisfied, or a maximum time of 20 minutes has occurred.
If after 20 minutes the system is still operating based on satisfying the
heating demand from zone 1, the system will terminate that demand.
The system will then shut system down for five (5) minutes. This will
allow for system temperatures and operating pressures to stabilize.
After a five 5 minute delay the system will begin operations to satisfied
the cooling demand from zone 2.
The system will continue to operate in this matter each time it receives a
zone call that is opposite of the current mode of operation (heating or
cooling).
B. Damper Operation
Cooling Operation Conventional Heat/Cool and Heat Pump Systems
When a in-zone thermostat makes a demand for cooling, the zone damper
opens and the cooling equipment begins operating.
Cooling demand is terminated when:
1.
All zone demands for cooling are terminated.
2.
The demand has exceeded the heat/cool changeover
time limit
(20minutes) while a heat demand exists.
When cooling demand is terminated, a 5 minute minimum off time delay is
initiated.
Second stage cooling is energized when the discharge air temperature is
7°F higher than the setpoint of the cooling staging temperature jumper.
