Honeywell RTH111 User Manual

Operation
1.1 Controls
1.2 Display screen
Setpoint indicator
Appears when the
setpoint temperature
is displayed.
Low-battery warning
1
When Cool On is flashing, this means the compressor protection is engaged (see
section 1.6).
1.3 System switch
Use the System switch to place the system in one of the following
modes.
• Cool: System is in Cooling mode.
• Off: System is off.
• Heat: System is in Heating mode.
CAUTION: EQUIPMENT DAMAGE HAZARD
Do not use Cooling mode when the outdoor temperature
is below 50 °F (10 °C).
1.4 Fan switch
Use the Fan switch to select the fan operation.
• Auto: The fan runs only when heating or cooling is actually taking
place (commonly used setting).
• On: The fan runs continuously. Use this setting for improved air
circulation or for more efficient air cleaning.
RTH111
1.
Fan switch
System switch
Temperature
adjustment buttons
Temperature
System status
• Cool On: Cooling is
1
activated.
• Heat On: Heating is
activated.
1.5 Temperature adjustment
Press the or button once to display the setpoint temperature.
Press either button more than once to change the setpoint.
The ambient (measured) temperature is normally displayed. To view
the setpoint temperature, press either of the temperature adjustment
buttons once. The setpoint temperature will appear for five seconds.
1.6 Built-in compressor protection
Your thermostat has a feature that helps prevent damage to the
compressor of your air conditioning system. Because damage can
occur if the compressor is restarted too soon after shutdown, this
feature forces the compressor to wait five minutes before restarting.
During the wait time, the message Cool On flashes on the screen.
When the safe wait time has elapsed, the message stops flashing
and the compressor turns on.

Battery replacement

Set the System switch to Off before removing the
batteries. Otherwise, the heating/cooling system could
remain activated even when batteries are removed.
Install two fresh AAA batteries when the low-battery icon flashes on
the screen. The icon appears for 60 days before the batteries are
depleted. Replace batteries once a year, or when you will be away for
more than a month.
The settings are stored in non-volatile (permanent) memory and are
thus saved when the thermostat is without batteries.

In case of difficulty

Screen is blank. • Ensure two fresh AAA alkaline batteries are
correctly installed.
Temperature settings • The System switch is off.
cannot be changed. • You are setting the temperatures outside
their allowable ranges:
• Heat: 40 °F to 90 °F (4.5 °C to 32 °C).
• Cool: 50 °F to 99 °F (10 °C to 37 °C).
Cool On is flashing. • The compressor protection delay has been
activated. Cooling will not be activated until
the delay ends (maximum of five minutes).
HI appears on the • The ambient (measured) temperature is
screen. above 122 °F (50 °C).
LO appears on the • The ambient (measured) temperature is
screen. below 32 °F (0 °C).
E1 appears on the • The temperature sensor circuit is opened.
screen. Replace the thermostat.
E2 appears on the • The temperature sensor circuit is shorted.
screen. Replace the thermostat.
RTH111

User Guide

Non-programmable Thermostat
69-2061EFS-01
11/09
69-2061EFS-01
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