White-Rodgers 1E78-151 Thermostat

The White-Rodgers 1E78-151 is a job-site staple for contractors looking for a reliable, vertical-profile 5/2 day programmable thermostat. This 70 Series economy model is engineered for single-stage 1H/1C HVAC systems, providing a seamless digital upgrade for older mechanical units without requiring a common wire (C-wire). It operates on 24V AC low voltage systems and is fully compatible with millivolt heating applications, making it a versatile choice for gas, oil, or electric furnaces and heat pumps without auxiliary heat.

The 1E78-151 digital thermostat features a clear, backlit LCD for visibility in low-light mechanical rooms and maintains a tight temperature differential of +/- 1 degree for consistent comfort. Its battery-powered design (2 AAA batteries) ensures maximum compatibility across vintage and modern installations. For the technician, the terminal designations RC, RH, W, Y, G, O, and B are clearly marked on the universal subbase, which is designed to mount directly to a 2x4 junction box or the wall surface to cover existing footprint marks.

Key Benefits:

• Universal Compatibility: Works with 24-volt and 750mV millivolt systems, including gas or oil furnaces, electric heat, and single-stage heat pumps.
• Precision Thermal Control: Adjustable room temperature calibration and a setpoint range of 45-90°F (7-32°C).
• Contractor-Friendly Install: Features a vertical low-profile design and a universal subbase that simplifies retrofitting from mechanical thermostats.
• Energy Management: Offers 5+2 day programming with 4 periods per day (Morning, Day, Evening, Night) to reduce utility loads during unoccupied hours.

Common Questions:

Does this thermostat require a common wire?
No, the 1E78-151 is battery-powered and does not require a C-wire for operation, making it ideal for 2-wire or 4-wire retrofit applications.

Can I use this for a heat pump system?
This model is compatible with single-stage heat pumps but does not support auxiliary or emergency heat stages. For multi-stage heat pump applications, a different 70 Series model would be required.

How do I switch between Fahrenheit and Celsius?
The unit features a selectable jumper or switch configuration on the circuit board (typically labeled W904) to toggle between temperature scales during the initial setup.

Disclaimer: While we strive for 100% accuracy, product data and specifications are subject to change. Please contact our team to confirm compatibility or technical details before purchasing.