Overview of Primary Product

EWC Controls Inc. 385 Highway 33 Englishtown, NJ 07726 800-446-3110 FAX [phone] E-Mail- [e-mail]
10
C
C
R
R
SA2
OD2
SENSOR
SENSOR
SA1
OD1
EXTERNAL
ONE ZONE
SWITCH
EXTERNAL 24-HOUR,
24VAC TIMER
24V INDICATOR
ONE
ZONE
ONE
ZONE
Figure 22. External One Zone switch.
Figure 23. External One Zone control using a 24-hour timer.
Figure 24. Supply air temperaure sensor.
Figure 25. Outdoor air temperature sensor.
The One Zone feature allows the
occupant to control all the zones from
a single thermostat by setting the
switch on the panel to ONE or using
an external switch connected to the
One Zone terminals shown in figure
22.
A homeowner can switch to One
Zone control when they leave for
vacation, and the Zone 1 thermostat
will control all zones. All zone dampers
will respond to the Zone 1 thermostat.
One Zone can also be used in
commercial applications with a
programmable thermostat in Zone 1
and mechanical thermostats in all
other zones. A timer can be used to
initiate the One Zone function (figure
23) and meet the requirements of
California Title 24.
An optional temperature sensor can
be used to limit supply air
temperature and prevent
overheating of the system during
heating or coil freeze-up during
cooling. The sensor is wired as shown.
A temperature sensor can be used to
monitor outdoor air temperature. This
sensor is required for the Moderate
weather option. If used with the
humidification option and an RH sensor,
the humidity set point will be automatically
adjusted to compensate for changing
outdoor temperatures. Frequent set point
changes are no longer required and
condensation on the windows is reduced.
The UZC3 has a number of LED
indicators that show the status of the
dampers, HVAC system and the panel
mode.
The STATUS LED blinks to indicate the
system is operating properly.
The HEATING LED is on continuosly to
indicate the panel is calling for stage1
heating and blinks when the panel
calls for stage 2 and stage 3 heating.
The COOLING LED is on continuosly to
indicate the panel is calling for stage
1 cooling and blinks when the panel
calls for stage 2 cooling.
The EMERGENCY HEAT LED indicates
when the panel is in emergency heat
mode in a heat pump system.
The FAN LED indicates when the panel
is activating the indoor fan.
The FRESH AIR LED indicates when the
panel is activating the indoor fan with
the outdoor air damper to bring in
fresh air.
The PURGE CYCLE LED indicates when
the panel is activating a purge cycle
by operating the indoor fan at the
end of a heating or cooling cycle.
One Zone
Control
Supply Air
Temperature
Sensor
Outdoor Air
Temperature
Sensor
LED Indicators
STATUS
HEATING
COOLING
EM HEAT
FAN
FRESH AIR
PURGE CYC
12AM
12PM
6AM6PM
(OPTIONAL)
(user supplied)
Supplied resistor
will remain if sensor
is not installed.
Supplied resistor
will remain if sensor
is not installed.
Model
OAS
Model
OAS
Model
SAS