Honeywell T8775A Non-Programable Thermostat User Guide
Setting SYSTEM and FAN Switches (T8775C only)
- System and Fan settings are controlled by using SYSTEM and FAN switches located on the top of the thermostat (see Fig. 1).
IMPORTANTDo not operate the T8775C in cooling mode when the outdoor temperature is below 50°F (10°C), or damage to compressor could result.
SET THE SYSTEM SWITCH:Heat: The thermostat controls your heating system.Off: Both heating and cooling systems are off.Cool: The thermostat controls your cooling system.
SET THE FAN SWITCH:Auto: Normal setting for most homes. The fan only runs with the heating and cooling system.On: The fan runs continuously. Use for improved air circulation.
Operating Your Thermostat
NOTE: Batteries are not required because the temperature setting is held permanently in memory.
Backlit Display
- The backlight can be turned on by turning the dial, or by pushing the backlight button as shown in Fig. 1.
Display Temperature Setting
NOTE: Your temperature setting can be set anywhere from 40°F to 90°F (4°C to 32°C) in heating and 45°F to 99°F (7°C to 37°C) in cooling (T8775C only).
- Turn the dial one click to display the current temperature setting. A▶ ROOM indicator points to Set when SET the temperature setting is displayed. If a change to the M19489 temperature setting is not made within five seconds, the mode will switch to the room temperature display.
- A▶ indicator points to Room when the room temperature is displayed.
Adjust Temperature Setting
- To lower the temperature setting, turn the dial counterclockwise.
- To raise the temperature setting, turn the dial clockwise.
Troubleshooting Guide
CAUTIONEquipment Damage Hazard. Can cause permanent damage to compressor or other equipment. Do not operate cooling when outside temperature is below 50°F (10°C). Allow compressor to remain off for five minutes before restarting. See equipment manufacturer instructions.
Heating or cooling does not come on.
- Make sure that the SYSTEM switch on the thermostat is set to Heat or Cool (T8775C only).
- In heating, make sure the temperature setting is above the room temperature and the flame is present in the display.
- In cooling, make sure the temperature setting is below the room temperature and a solid snowflake is present in the display (T8775C only).
- If a call for cooling is made before the compressor has been off for five minutes, or if a power interruption occurs while the compressor is running, the thermostat will go into a five-minute delay to protect the compressor. The snowflake will flash during this delay.
- Check the system fuse or circuit breaker and replace or reset if necessary.
- Check for air movement at the register.
is present in the display (T8775C only).If you have questions concerning this thermostat, call Customer Care at 1-800-468-1502.
Resideo Technologies, Inc. 1985 Douglas Drive North, Golden Valley, MN 55422 1-800-468-1502 69-1679EF–03 M.S. Rev. 03-20 | Printed in U.S.A.
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