The development of the 9400 family of five Robertshaw thermostats was based on the findings of market research, which also contributed to the development of the Invensys 9700i Series, the industry's most innovative programmable thermostats.

Market research found that contractors and consumers wanted a display that was easier to read. The LCD display is 80 percent larger than competitive models and back lit so users can view the temperature in a dark room.

Other features of thermostats in the 9400 series include:

• Front load battery door - Allows batteries to be easily accessed in the front of the unit. (Models 9400 and 9405)
• Worry-free memory storage - Maintains setpoint and programmed settings during power outages. (Models 9401, 9415 and 9420)
• Low temperature freeze protection - Activates the heat automatically when temperatures fall below 40 degrees Fahrenheit to protect pipes from freezing. (Models 9400 and 9405)
• Permanent winter and summer setpoint memory - Eliminates temperature adjustments when switching systems for seasonal requirements. (Models 9400, 9401, 9415 and 9420)
• Adjustable first and second stage temperature differential - Maintains optimal customer comfort. (Models 9415 and 9420)
• Zoning sensor - Thermostat acts as a sensor within the system in zoning applications where temperature is precisely controlled. (Models 9400, 9401, 9415 and 9420)

Each of the thermostats in the series has been designed to fit different applications. Models are available that are compatible with gas, oil and electric heating and cooling systems as well as heat pumps; 24 Volt AC and millivolt systems; and single and multi-stage systems.