Specifications
| General | |
| Manufacturer | Emerson |
| Brand | Sensi |
| Manufacturer Product No. | ST55 |
| UPC | 683318654648 |
| Program Options | Programmable - 7 Day or Non-Programmable |
| Program Periods Per Day Options | 8 Max |
| Battery Power Rating | 0 to 30 Vac, 50/60 Hz or DC |
| Terminals | RC, RH, C, W/E, W2, Y, Y2, O/B/2, G, L |
| 3-Wire Zone Valve Connections | Yes |
| Millivolt Compatible | No |
| Economizer Connections | No |
| Humidity Control | Displays indoor humidity |
| Heat Pump Dual Fuel Control | Yes (Remote Sensor Not Required) |
| Heat Pump Auxiliary Lockout Control - Outdoor Sensor Option | None |
| Remote Sensor Options | None |
| Auto Changeover (Heat/Cool) | Yes |
| Fan Option | Auto, On |
| Filter Change Reminder | Yes |
| Early Start | Yes |
| Keypad Lockout | Total Lockout |
| Set-Point Temperature Limits | No |
| Backlight | Yes; Continuous Backlight with Common Wire |
| Voltage | 20-30 Vac, NEC Class II, 50/60Hz |
| Amp Rating | 0.05 to 1.5 Amps (load per terminal) 1.5 Amps maximum load (all terminals combined) |
| Rated Differential, Universal | Heat (Conventional Gas, Oil, Electric): 0.5°F (Fast) 0.75°F (Med) 1.9°F (Slow); Cool (Central Air): 0.9°F (Fast) 1.2°F (Med) 1.7°F (Slow); Heat Pump: 0.9°F (Fast) 1.2°F (Med) 1.7°F (Slow); Aux. Heat: 0.5°F (Fast) .75°F (Med) 1.9°F (Slow) |
| Ambient Operating Temperature | 32° to 105°F (0 to 40°C) |
| Operating Humidity | 90% non-condensing maximum |
| Shipping Temperature Range | -20 to 150°F (-29 to 66°C) |