E M Heat is simply emergency heat. It would be what you would use if your heat pump would become inoperable. It bypasses the pump and allows you to use the heat strips in your furnace like a normal furnace.
answered 2 months, 1 week ago
The Honeywell YRTH3100C1011 system switch has four positions. From left to right, they are: Cool, Off, Heat, and Em Heat.
The SYSTEM switch allows you thermostat to be set to control your heating or cooling system, depending on the season.
The function of each position is:
• Cool: Cooling system control.
• Off: All systems are off.
• Heat: Heating system control.
• Em Heat: Emergency & Auxiliary Heat control. Compressor is locked out.
If you do have additional questions, please contact the Honeywell Consumer Technical Support line at 1-800-468-1502.