Honeywell RTH221 - In case of difficulty; Screen Issues and Settings Lock; Compressor Protection Delay Issues; Temperature Display and Sensor Errors

Operating Manual
16
In case of difficulty
Screen is blank. • Ensure two fresh AAA alkaline batteries are correctly installed.
Temperature settings cannot be
changed.
• The System switch is off.
• You are setting the temperature outside its allowable range:
• 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 or Heat On is flashing. • The compressor protection delay is underway. Wait for the delay
to end (maximum of 5 minutes).
HI appears on the screen. • The ambient (measured) temperature is above 122°F (50°C).
LO appears on the screen. • The ambient (measured) temperature is below 32°F (0°C).
E1 appears on the screen. • The temperature sensor circuit is opened. Replace the thermostat.
E2 appears on the screen. • The temperature sensor circuit is shorted. Replace the thermostat.