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TROUBLESHOOTING
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
interlock 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
usually indicates the thermostat is operating properly. If
the thermostat 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 five 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 de-
scribed 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 operates 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 Configuration
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 influencing 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
Configuration menu, step 7 (heat) or 8 (cool). If an ac-
ceptable cycle rate is not achieved, contact a local HVAC
service person for additional suggestions.
Forgot Keypad
Lockout Code
Press the menu
key (key will disappear) and hold in for
20 seconds. This unlocks the thermostat.
Blank display any or keypad
not responding
1. Voltage Spike or static discharge Use the Reset Operation shown above.
"Call for Service" on display
Power applied to thermostat "L" terminal Indicates the heat pump system is sending a signal (volt-
age) to the thermostat terminal marked "L". It does not
indicate a malfunction in the thermostat. The manufac-
turer of the Heat Pump system can determine the likely
cause of Call for Service on the thermostat by identifying
the component in the system sending power to the "L"
terminal.
Reset Operation
Note: When thermostat is reset, installer configuration 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 thermo-
stat 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 configuration menu settings.
To reset the programming, clock and configuration settings, press the
and and SYSTEM keys simultaneously. The
thermostat should go blank and then all segments will be displayed momentarily.
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