Troubleshooting - Emerson 1F85U-22NP Installation And Operating Instructions Manual

Symptom Possible Cause
1.) Blown fuse or tripped circuit
2.) Furnace power switch to OFF
No Heat/
No Cool/
3.) Furnace blower compartment
No Fan
(common problem)
4.) Loose connection to thermostat
1.) System not set to Heat
2.) Loose connection to thermostat
3.) Heating System requires
No Heat
1.) System not set to Cool
2.) Loose connection to thermostat
3.) Cooling System requires
No Cool
Heat, Cool or Fan Possible short in wiring, thermostat,
Runs Constantly heat, cool or fan system
Thermostat
Display & Thermostat display requires
Thermometer adjustment
Disagree
Furnace (Air
Conditioner)
The location of the thermostat and/
Cycles Too Fast or
or the size of the Heating System
Slow (narrow or
may be influencing the cycle rate
wide temperature
swing)
(Troubleshooting continued on next page)

TROUBLESHOOTING

breaker
door panel loose or not properly
installed
or system
or system
service or thermostat requires
replacement
or system
service or thermostat requires
replacement
Corrective Action
1.) Replace fuse or reset breaker
2.) Turn switch to ON
3.) Replace door panel in proper position to engage
safety interlock or door switch
4.) Tighten Connections
1.) Set thermostat to Heat.
2.) Verify thermostat and system wires are securely
attached.
3.) Diagnostic: Set System to Heat and raise the
setpoint above room temperature. Within five
minutes the thermostat should make a soft click
sound and "Heat On" should appear on display.
This sound 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 system is operating correctly.
1.) Set thermostat to Cool.
2.) Verify thermostat and system wires are securely
attached.
3.) Diagnostic: Set System to Cool and lower setpoint
below room temperature. Same procedures 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
if the compressor lock-out option is selected in the
installer menu. (see INSTALLER MENU, item 50)
Check each wire connection to verify they are not
shorted or touching other wires. Try resetting the
thermostat. If the condition persists contact your
HVAC service person.
Display can be adjusted +/-5°. See User Menu item
05
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. If you would like to increase
cycle time, choose SLO for slow cycle in the
Installer menu. (Reference menu items 30, 32 &
35.) If an acceptable cycle rate is not achieved,
contact your HVAC service person.
7