White Rodgers 1F78 User Manual page 6

7 TROUBLESHOOTING
CONTINUED FROM FIFTH PAGE
Symptom
Heat, Cool or Fan Runs Constantly.
Furnace Cycles Too Fast or Too Slow
(narrow or wide temperature swing)
Cooling Cycles Too Fast or Too Slow
(narrow or wide temperature swing)
Thermostat Setting and Thermostat
Thermometer Disagree
Blank Display and/or Keypad
Not Responding
The Emerson logo is a
trademark and a service mark
of Emerson Electric Co.
Possible Cause
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.
1. The location of the thermostat and/or the
size of the Heating System may be
influencing the cycle rate.
1. The location of the thermostat and the size
of the Cooling System can influence the
cycle rate.
1. Thermostat thermometer setting requires
adjustment.
1. Voltage spike or static discharge.
2. Battery change required.
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Corrective Action
Check each wire connection to verify they are not
shorted or touching together. No bare wire should
stick out from under terminal screws. 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 operates correctly, replace the thermostat.
Digital thermostats normally provide precise
temperature control and may cycle faster than
some older mechanical models. A faster cycle
rate means the unit turns on and off more
frequently but runs for a shorter time so there is
no increase in energy use. If you would like to
increase the cycle time, clip Jumper W-905 as
mentioned in the instructions for Hydronic Heating
Systems. It is not possible to shorten the cycle
time. If an acceptable cycle rate is not achieved as
received or by clipping W-905 contact a local
service person for additional suggestions.
The cycle rate for cooling is fixed and can not be
adjusted. Contact a local service person for
suggestions.
The thermometer can be adjusted +/- 3 degrees.
See Temperature Display Adjustment in the
Operation section.
Replace batteries and check heat/cool system
for proper operation. If a voltage spike occurs use
the Reset Operation listed above.