Troubleshooting - White Rodgers 850 Installation Instructions Manual

TROUBLESHOOTING

8
CONTINUED FROM SEVENTH PAGE
Symptom
No Heat (continued)
No Cool
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
Thermostat Does Not Follow Program
Blank Display and/or Keypad
Not Responding
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trademark and a service mark
of Emerson Electric Co.
Possible Cause
5. Heating system requires service or
thermostat requires replacement.
1. SYSTEM Switch not set to COOL.
2. Loose connection to thermostat or system.
3. Cooling system requires service or
thermostat requires replacement.
1. FAN Switch set to Fan ON.
2. Possible short in wiring.
3. Possible short in thermostat.
4. Possible short in heat/cool/fan system.
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. AM or PM set incorrectly in program.
2. AM or PM set incorrectly on the clock.
3. Voltage spike or static discharge.
1. Voltage spike or static discharge.
2. Battery change required.
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Corrective Action
Diagonistic: 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 below.
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 is operating
correctly.
Set SYSTEM Switch to COOL and lower temperature
below room temperature.
Verify thermostat and system wires are securely
attached.
Same procedure 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.
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 below. 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.
Check current clock and program settings
including the AM or PM designations for each
time period. If a voltage spike or a static discharge
occurs use the Reset Operation listed below.
Replace batteries and check heat/cool system
for proper operation. If a voltage spike occurs use
the Reset Operation listed below.