White Rodgers 1F87-251 - Manual (Page 8)

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
panel loose or not properly installed. safety interlock or door switch.
No Heat 1. Pilot light not lit. Re-light pilot.
2. SYSTEM Switch not set to HEAT. Set SYSTEM Switch to HEAT and raise setpoint
above room temperature.
3. Loose connection to thermostat or system. Verify thermostat and system wires are securely Attached.
4. Furnace Lock-Out Condition. Heat may also Many furnaces have safety devices that shut the system
be intermittent. down when a lock-out condition occurs. If the heat works
intermittently contact the furnace manufacturer or local
service person for assistance.
5. Heating System requires service or Diagonistic: Set SYSTEM Switch to HEAT and raise the
thermostat requires replacement. 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 service person to verify the heating system is
operating correctly.
No Cool 1. SYSTEM Switch not set to COOL. Set SYSTEM Switch to COOL and lower setpoint below
room temperature.
2. Loose connection to thermostat or system. Verify thermostat and system wires are securely attached.
3. Cooling System requires service or thermostat Same procedure as diagnostic for No Heat condition
requires replacement. 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 if
the compressor lock-out option is selected in the
configuration menu (Item 6).
Heat, Cool or Fan Runs Constantly 1. FAN Switch set to Fan ON. Check each wire connection to verify they are not
2. Possible short in wiring. shorted or touching together. No bare wire should
3. Possible short in thermostat. stick out from under terminal screws.
4. Possible short in Heat/Cool/Fan system. Try resetting the thermostat. 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.
Furnace Cycles Too Fast or Too Slow 1. The location of the thermostat and/or the size Item 2 in the Configuration Menu is the adjustment
(narrow or wide temperature swing) of the Heating System can influence the cycle rate. that controls the cycle rate. If an acceptable cycle
rate is not achieved using the FA (Fast) or SL
(Slow) adjustment contact a local service person for
additional suggestions.
Cooling Cycles Too Fast or Too Slow 1. The location of the thermostat and/or the size of the The cycle rate for cooling is fixed and can not be adjusted.
(narrow or wide temperature swing) Cooling System may be influencing thecycle rate. Contact a local service person for suggestions.
Thermostat Setting and Thermometer 1. Thermostat thermometer setting requires The thermometer can be adjusted +/- 4 degrees as listed
Disagree adjustment. in item 7 of the Configuration Menu. No other adjustment
is possible.
Clock Loses or Gains Time 1. Loss of power to thermostat and low batteries. The thermostat will maintain its program in memory even
with no power/no batteries but the clock time will be
incorrect when power is restored. See No Heat/No Cool/
No Fan (common problems) above for items to check in
the system.
Heat or Cool Starts Early 1. EMR activated See Configuration Menu (Item 4).
Thermostat Does Not Follow Program 1. AM or PM set incorrectly in program. Check current clock and program settings including
2. AM or PM set incorrectly on the clock. the AM or PM designations for each time period.
3. Voltage spike or static discharge. If a voltage spike or static discharge occurs use the
Reset Operation listed above.
Blank Display and/or Keypad Not 1. Loss of power and dead batteries. Replace batteries and check heat/cool system for
Responding 2. Voltage Spike or Static Discharge. proper operation. If a voltage spike or static discharge
occurs use the Reset Operation listed above.
TROUBLESHOOTING (cont.)