Robertshaw RS4320C USERS MANUAL - Manuel (Page 9)

Two Stage Systems
A 2nd stage is a second or additional system that
will provide extra heating or cooling. When a
2nd stage is operating the display will show the
number 2 by the heat/cool icons.
A temperature differential (default value is 2.0 °F or 1.0 °C) and time
delay (default value 20 minutes) control the 2nd stage cycle.
Operation of the 2nd stage begins when:
• The room temperature changes from the setpoint by the sum of the
1st and 2nd stage differential settings.
• The first stage has been on for the specified delay time, but the
heating/cooling demand has not yet been met.
Three Stage Systems
A 3rd stage is a third or additional system that will
provide extra heating in heat pump applications.
When a 3rd stage is operating the display will
show the number 2 and E by the heat icon.
A time delay (default value 20 minutes) controls the 3rd stage cycle.
This time delay starts when the second stage turns on.
Backlit Display
This thermostat is equipped with a backlight to make viewing the display
easy. Press the button to activate the backlight. The backlight will
turn off after 10 seconds of inactivity. If the thermostat is wired to have
the backlight stay on all the time the night light can be turned on/off in
the settings menu.
Automatic Shut-Down
The thermostat will not display the room temperature if the temperature
goes higher than 99 °F (37 °C) or lower than 32 °F (0 °C).
The display will show HI or LO. The thermostat continues to control
heating and cooling and will resume the display of real time information
when the room temperature is back inside the display’s range.
Setting The Fan To ON, AUTO or CIRC
The fan has 3 settings: On, Auto, or Circ. Press the button to switch
among the three.
ON: The fan is on constantly. The status of the heating/cooling
equipment has no effect on the fan.
AUTO: Whenever there is a call for heating or cooling the fan will turn on.
CIRC: The fan operates in a cycle of on for 10 minutes and off for 20
minutes. Whenever there is a call for heating or cooling the
cycle stops and the fan responds to the call. The fan circulation
resumes when the call for heating or cooling is satisfied.
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