Honeywell RTH2510 User Manual

Page of 44
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.
69-2381ES-01 (RTH2510 7-day OM) ENG USA.fm  Page 16  Tuesday, October 20, 2009  11:18 AM