Honeywell RTH221B Owner's Manual - Page 1

 Operation 1.1 Controls Press to set clock or schedule Press to override schedule and hold temperature Press to run (follow) programmed schedule 1. Fan switch System switch Temperature adjustment buttons 1.2 Display screen Setpoint indicator Appears when the setpoint temperature is displayed. Low-battery warning Permanent schedule override Schedule period Clock Temporary schedule override Temperature System status • Cool On: Cooling is activated. 1 • Heat On: Heating is activated. 1 When Cool On is flashing, this means the compressor protection is engaged (see section 1.7). 1.3 Setting the clock  Press the Set button. The message Set Time will appear on the screen and the time display will flash.  Press the  or  button to set the time.  Press the Run button to save the changes & exit. (The changes are also saved if you do not press any button for 60 seconds.) NOTE: The clock has lost its settings when the time display flashes. If the thermostat is following the programmed schedule, it will use the temperature settings programmed for the Wake period until you readjust the clock. 1.4 System switch Use the System switch to place the system in one of the following modes. • Cool: System is in Cooling mode. • Off: System is off. • Heat: System is in Heating mode. CAUTION: EQUIPMENT DAMAGE HAZARD Do not use Cooling mode when the outdoor temperature is below 50 °F (10 °C). RTH221 RTH221 User Guide Programmable Thermostat 1.5 Fan switch Use the Fan switch to select the fan operation. • Auto: The fan runs only when heating or cooling is actually taking place (commonly used setting). • On: The fan runs continuously. 1.6 Temperature setting Press the  or  button once to display the setpoint temperature. Press either button more than once to change the setpoint. The ambient (measured) temperature is normally displayed. To view the setpoint temperature, press either of the temperature adjustment buttons once. The setpoint temperature will appear for five seconds. 1.7 Built-in compressor protection Your thermostat has a feature that helps prevent damage to the compressor of your air conditioning system. Because damage can occur if the compressor is restarted too soon after shutdown, this feature forces the compressor to wait five minutes before restarting. During the wait time, the message Cool On flashes on the screen. When the safe wait time has elapsed, the message stops flashing and the compressor turns on.  Programmed schedule 2. 2.1 Using the schedule Press the Run button to follow the programmed schedule. You can have up to four periods in one day. Each period can be programmed with a different temperature setting. Wake Leave Return Sleep Morning temperature Daytime temperature Evening temperature Night temperature To program a period, you need to set its start time and its two temperature settings (one when the thermostat is in cooling mode and another one when it is in heating mode). The same period and settings are repeated every day. For maximum energy savings without sacrificing comfort, you can program the schedule such that the temperature is at an economical level when you sleep or are away during the day and at a comfortable level when you are awake and at home. 2.2 Factory settings Period Wake Leave Return Sleep Start time 6:00 a.m. 8:00 a.m. 6:00 p.m. 10:00 p.m. Heat 70 °F (21 °C) 62 °F (16.5 °C) 70 °F (21 °C) 62 °F (16.5 °C) Cool 75 °F (24 °C) 83 °F (28.5 °C) 75 °F (24 °C) 78 °F (25.5 °C) 69-2062EFS-01 1/8