User Manual Honeywell T8775A1009/U The Digital Round® Non-Programmable Thermostat

CAUTION Electrical Shock or Equipment Damage Hazard. Can shock individuals or short equipment circuitry. Disconnect power supply before installation.

Location

Install the thermostat about 5 ft (1.5m) above the floor in an area with good air circulation at average temperature. Do not install the thermostat where it can be affected by:

drafts or dead spots behind doors and in corners.
hot or cold air from ducts.
radiant heat from the sun or appliances.
concealed pipes and chimneys.
unheated (uncooled) areas such as an outside wall behind the thermostat.

Mounting Wallplate to Wall

Mount the T8775A,C wallplate, with the screws provided.

Wiring

IMPORTANT: Use 18-gauge wire to wire the T8775A,C Thermostats.
All wiring must comply with local electrical codes and ordinances. Disconnect the power supply to prevent electrical shock or equipment damage.

CUSTOMIZE THERMOSTAT

Setting Fuel Switch (T8775C only)

The fuel switch is preset at the factory in the F position. See Fig. 7. This is the correct setting for gas or oil systems. If the T8775C is being installed on an electric heat system, or a heat pump, set the switch to the E position. The E setting allows the fan to turn on immediately with the heating equipment in a system where the G terminal is connected.

DIP Switch

To adjust the heat cycle rate or the Fahrenheit/Celsius indication, locate DIP switch 1, 2 and 3 on the back of the thermostat. See Fig. 8.

Set Heat Cycle Rate

Use DIP switches 1 and 2 to set the heat cycle rate. See Table 1.

Indication Use DIP switch 3 to set the desired temperature indication. See Table 2.

Mounting Thermostat to Wallplate

OPERATION

Setting SYSTEM and FAN Switches (T8775C only)

System and fan settings are controlled manually by using the switches located at the top of the thermostat. See Fig. 10.

SYSTEM Switch

Heat: The thermostat controls the heating system.
Off: Both heating and cooling systems are off.
Cool: The thermostat controls the cooling system.

FAN Switch

Auto: The fan only runs with the heating and cooling system.
On: The fan runs continuously. Use for improved air circulation

CHECKOUT

NOTE: Temperature setpoint range is 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.

Heating

Slide the SYSTEM switch to Heat and the FAN switch to Auto (T8775C only).
Raise the temperature setpoint several degrees above the room temperature.
A flame will appear in the display and the heat should turn on.
Lower the temperature setpoint below the room temperature.
The flame will disappear from the display and the heat should turn off.

Cooling (T8775C only)

CAUTION Low Temperature Hazard. Operating at too low of an outdoor temperature may cause compressor damage. Do not operate cooling if outdoor temperature is below 50°F (10°C). Refer to manufacturerís recommendations.

NOTE: 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.

Slide the SYSTEM switch to Cool and the FAN switch to Auto.
Lower the temperature setpoint several degrees below the room temperature.
After approximately five minutes, the thermostat will display a solid snowflake and the cooling should turn on.
Raise the temperature setpoint above the room temperature.
The snowflake will disappear from the display and the cooling should turn off.

Fan

Slide the SYSTEM switch to Off and the FAN switch to On. The fan should run continuously.
Slide the FAN switch to Auto. The fan should turn off.

Automation and Control Solutions

Honeywell International Inc. Honeywell Limited-Honeywell LimitÈe
1985 Douglas Drive North: 35 Dynamic Drive
Golden Valley, MN 55422: Scarborough, Ontario M1V 4Z9

OWNER’S 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).

IMPORTANT: Do 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 indicator points to Set when the temperature setting is displayed. If a change to the 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

CAUTION: Equipment 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.