
Do you have a question about the Honeywell RTH221 and is the answer not in the manual?
| Stages | 1 Heat/1 Cool |
|---|---|
| Voltage | 24V |
| Temperature Range | 40°F to 90°F (4°C to 32°C) |
| Backlight | No |
| Display | Digital |
| Power Source | Battery |
| Compatibility | Single-stage heating and cooling systems |
| Dimensions | 3.75" H x 4.5" W x 1" D (9.5 cm x 11.4 cm x 2.5 cm) |
Lists key features like ambient temperature display, one-touch setpoint access, and schedule savings.
Describes the function of the Set, Hold, Run, and Up/Down buttons on the thermostat.
Defines the four daily schedule periods: Wake, Leave, Return, and Sleep for energy savings.
Troubleshooting for blank screen or when temperature settings cannot be changed.
Explains flashing Cool On/Heat On indicators due to compressor protection.
Interprets HI, LO, E1, E2 messages indicating temperature issues or sensor faults.










