Robertshaw 9520 - Manual (Page 9)

◆ Changing Temperature Differential
IMPORTANT: The temperature differential is factory set at 1 (1°). This
means that whenever the room temperature changes by one half of a
degree from the temperature setting, the system will turn on. If the system
turns on too often, increase the temperature differential.
1. Press both and buttons
at the same time and hold for one
second. The display will show:
2. Press either the or button
to adjust the temperature
differential up or down.
The display will return to the room temperature five
seconds after the last input.
◆ Changing Fahrenheit (F) to Celsius (C)
The thermostat is preset to display the temperature in degrees Fahrenheit.
You may change the display to Celsius if desired.
1. Move the manual switch marked F (Fahrenheit) and C (Celsius)
located at the top center of the circuit board to the desired setting
(see page 7).
2. Press RESET button located to the right of the LCD display to register
the change.
The display will change to show the temperature in your desired tempera-
ture scale. To return the thermostat to its original setting, repeat steps 1
and 2 above.
◆ LED Indicators
The LED indicators are used to indicate system activity. The AUX indicator
illuminates during a call for second stage heating. The auxiliary stages are
used to maintain comfort during extremes in weather conditions. If the
AUX LED is illuminated too frequently during periods of moderate temper-
ature, check the differential settings (see above).
The CHECK indicator is used to monitor system status. If the CHECK indi-
cator is illuminated, call your local HVAC service provider.
The EMER indicator is illuminated only when the system switch is moved
to the EM, emergency heat position. The EM position is used only when
the primary stage of heat is not functioning or requires service.
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COOL-OFF-HEAT-EM AUTO - ON AUX >
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CHECK EMER
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