White Rodgers NP110 Install Manual page 24

Symptom
Heat, Cool or Fan Runs Constantly.
Furnace Cycles Too Fast or Too Slow
(narrow or wide temperature swing)
24
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.
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 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.