- Emerson Thermostat User Manual
Symptom Possible Cause Corrective Action
No Heat/No Cool/No Fan
(common problems)
1. Blown fuse or tripped circuit breaker.
2. Furnace power switch to OFF.
3. Furnace blower compartment door or
  panel loose or not properly installed.
4. Loose connection to thermostat or system.
Replace fuse or reset breaker.
Turn switch to ON.
Replace door panel in proper position to engage safety inter-
lock or door switch.
Tighten connections.
No Heat 1. Pilot light not lit.
2. Furnace Lock-Out Condition. Heat
  may also be intermittent.
3. Heating system requires service or
  thermostat requires replacement.
Re-light pilot.
Many furnaces have safety devices that shut down when 
a lock-out condition occurs. If the heat works intermittently 
contact the furnace manufacturer or local HVAC service 
person for assistance.
Diagnostic: Set SYSTEM Switch to HEAT and raise the 
setpoint above room temperature. Within a few seconds the 
thermostat should make a soft click sound. This sound usu-
ally indicates the thermostat is operating properly. If the ther-
mostat does not click, try the reset operation listed above. If 
the thermostat does not click after being reset contact your 
heating and cooling service person or place of purchase for 
a replacement. If the thermostat clicks, contact the furnace 
manufacturer or a HVAC service person to verify the heating 
is operating correctly.
No Cool 1. Cooling system requires service or
  thermostat requires replacement.
Same as diagnostic for No Heat condition except set the 
thermostat to COOL and lower the setpoint below the room 
temperature. There may be up to a fi ve minute delay before 
the thermostat clicks in Cooling.
Heat, Cool or Fan
Runs Constantly
1. Possible short in wiring.
2. Possible short in thermostat.
3. Possible short in heat/cool/fan system.
4. FAN Switch set to Fan ON.
Check each wire connection to verify they are not shorted or 
touching together. No bare wire should stick out from under 
terminal block. Try resetting the thermostat as described 
above. If the condition persists the manufacturer of your 
system or service person can instruct you on how to test the 
Heat/Cool system for correct operation. If the system oper-
ates correctly, replace the thermostat.
Thermostat Setting &
Thermostat Thermometer 
Disagree
1. Thermostat thermometer setting
 requires adjustment.
The thermometer can be adjusted +/- 4 degrees. See 
Temperature Display Adjustment in the Confi guration Menu 
section.
Furnace (Air Conditioner)
Cycles Too Fast or Too 
Slow (narrow or wide 
temperature swing)
1. The location of the thermostat and/or
  the size of the Heating System may
 be infl uencing the cycle rate.
Digital thermostats provide precise control and cycle faster 
than older mechanical models. The system turns on and off 
more frequently but runs for a shorter time so there is no 
increase in energy use. If you would like an increased cycle 
time, choose SL for slow cycle in the Confi guration menu, 
step 6 (heat), 7 (cool) or 8 (heat pump). If an acceptable 
cycle rate is not achieved, contact a local HVAC service 
person for additional suggestions.
TROUBLESHOOTING 
Reset Operation
Note: When thermostat is reset, installer confi guration menu settings and programming will reset to factory settings.
If a voltage spike or static discharge blanks out the display or causes erratic thermostat operation, you can reset the thermostat by removing 
the wires from terminals R and C (do not short them together) and removing batteries for 2 minutes. After resetting the thermostat, replace the 
wires and batteries. If the thermostat has been reset and still does not function correctly contact your heating/cooling service person or place 
of purchase. 
Note: Be sure to review the installer confi guration menu settings.
To reset the programming, clock and confi guration settings, press 
 and   and the FAN button simultaneously. The thermostat should 
go blank and then all segments will be displayed momentarily.
www.white-rodgers.com
HOMEOWNER HELP LINE: 1-800-284-2925
White-Rodgers is a division
of Emerson Electric Co.
The Emerson logo is a 
trademark and service mark
of Emerson Electric Co.










