TROUBLESHOOTING
Reset Operation
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.
To reset the programming, clock and configuration settings, pressandand the SYSTEM button simultaneously. The thermostat should go blank and then all segments will be displayed momentarily.
Symptom | Possible Cause | Corrective Action | |
No Heat/No Cool/No Fan | 1. | Blown fuse or tripped circuit breaker. | Replace fuse or reset breaker. |
(common problems) | 2. | Furnace power switch to OFF. | Turn switch to ON. |
| 3. | Furnace blower compartment door or | Replace door panel in proper position to engage safety |
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| panel loose or not properly installed. | interlock or door switch. |
| 4. | Loose connection to thermostat or system. | Tighten connections. |
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No Heat | 1. | Pilot light not lit. | |
| 2. | Furnace | Many furnaces have safety devices that shut down when a |
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| may also be intermittent. | |
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| contact the furnace manufacturer or local HVAC service |
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| person for assistance. |
| 3. | Heating system requires service or | Diagnostic: Set SYSTEM Switch to HEAT and raise the |
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| thermostat requires replacement. | setpoint above room temperature. Within a few seconds |
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| the thermostat should make a soft click sound. This sound |
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| usually indicates the thermostat is operating properly. If |
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| the thermostat does not click, try the reset operation listed |
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| above. If the thermostat does not click after being reset |
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| contact your heating and cooling service person or place |
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| of purchase for a replacement. If the thermostat clicks, |
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| contact the furnace manufacturer or a HVAC service |
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| person to verify the heating is operating correctly. |
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No Cool | 1. | Cooling system requires service or | Same as diagnostic for No Heat condition except set the |
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| thermostat requires replacement. | thermostat to COOL and lower the setpoint below the |
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| room temperature. There may be up to a five minute delay |
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| before the thermostat clicks in Cooling. |
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Heat, Cool or Fan | 1. | Possible short in wiring. | Check each wire connection to verify they are not shorted |
Runs Constantly | 2. | Possible short in thermostat. | or touching together. No bare wire should stick out from |
| 3. | Possible short in heat/cool/fan system. | under terminal block. Try resetting the thermostat as |
| 4. | FAN Switch set to Fan ON. | described above. If the condition persists the manufacturer |
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| of your system or service person can instruct you on how |
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| to test the Heat/Cool system for correct operation. If the |
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| system operates correctly, replace the thermostat. |
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Thermostat Setting & | 1. | Thermostat thermometer setting | The thermometer can be adjusted +/- 4 degrees. See |
Thermostat Thermometer |
| requires adjustment. | Temperature Display Adjustment in the Configuration |
Disagree |
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| Menu section. |
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Furnace (Air Conditioner) | 1. | The location of the thermostat and/or | Digital thermostats provide precise control and cycle faster |
Cycles Too Fast or Too Slow |
| the size of the Heating System may | than older mechanical models. The system turns on and |
(narrow or wide |
| be influencing the cycle rate. | off more frequently but runs for a shorter time so there is |
temperature swing) |
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| no increase in energy use. If you would like an increased |
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| cycle time, choose SL for slow cycle in the Configuration |
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| menu, step 6 (heat) or 7 (cool). If an acceptable cycle rate |
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| is not achieved, contact a local HVAC service person for |
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| additional suggestions. |
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Forgot Keypad |
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| Press the Menu button (button will disappear) and hold in |
Lockout Code |
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| for 15 to 20 seconds. This unlocks the thermostat. |
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The Emerson logo is a trademark and service mark of Emerson Electric Co.
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