Honeywell T8400C Installation Instructions - Page 4

T8400C AND T8401C ELECTRONIC THERMOSTATS Slide the FAN switch in the bottom left corner of the thermostat to select the desired fan setting. SYSTEM Switch System switch settings control thermostat operation as follows: Cool: The thermostat controls the cooling system. Off: Both heating and cooling are off. Heat: The thermostat controls the heating system. Slide the SYSTEM switch in the bottom right corner of the thermostat to select the desired system setting. TEMPERATURE DISPLAY Set Room INCREASE SETTING DECREASE SETTING FAN Auto On SYSTEM Cool Off Heat 3. To increase the temperature setpoint press the s key. Each press changes the setpoint one degree; press and hold to change the setpoint several degrees. M14681 4. To decrease the temperature setpoint press the t key. Each press changes the setpoint one degree; press and hold to change the setpoint several degrees. M14682 Setting °F/°C Indication and Heat Cycle Rate NOTE: To save changes to the °F/°C indication and the heat cycle rate, all seven steps must be completed. To set the °F/°C indication and heat cycle rate: 1. If the temperature is displayed in °F, set the temperature setpoint to 52°F. If the room temperature is displayed in °C, set the temperature setpoint to 11°C. FAN SWITCH SYSTEM SWITCH M18417 Fig. 8. Digital display and system switches (FAN and SYSTEM). Set Temperature Setpoint NOTE: Temperature setpoint range is 40° to 99°F (5° to 37°C). The temperature setpoint and the room temperature are shown separately on the digital display. The t indicator points to Set when the temperature setpoint is displayed and to Room when the room temperature is displayed . Set Room INDICATOR ROOM TEMPERATURE SETPOINT TEMPERATURE M14679 To set temperature setpoint: 1. Select Heat or Cool by sliding the SYSTEM switch in the lower right corner of the thermostat to the desired mode. See Fig. 8. 2. To display the temperature setpoint on the digital display, press either the s or t key once. The temperature setpoint is displayed for approxi-mately five seconds as the indicator points to Set and flashes. M14680 M14683 OPTIONAL SYSTEM CHECKOUT When in steps 2 and 3 only, the t key can be used to turn heat or cool outputs on and off. Change the SYSTEM switch setting to test heat or cool outputs. No action takes place If the system switch is in the Off position. Examples: System setting at HEAT: If heat is on, the t key turns it off; if heat is off, t turns it on. M14684 System setting at COOL: If cool is on, t key turns it off; if cool is off, t turns it on. M14685 2. Press the st keys simultaneously for more than one second to light all segments on display and to enter installer setup mode. When the keys are released, a two-digit software revision code is displayed. NOTE: M14686 In installer setup mode only, each press of the s key momentarily displays 01. Each press of the t key momentarily displays 02. When the keys are released, these two-digit codes are no longer displayed. 69-1480-1 4