Troubleshooting - Emerson 1F75P-21NP 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 Switch not set to Heat
2.) Loose connection to thermostat
3.) Heating System requires
No Heat /
No First Stage
Heat
4.) Misconfiguration between menu
5.) O/B Switch set incorrectly
1.) System Switch not set to Cool
2.) Loose connection to thermostat
3.) Cooling System requires
No Cool
4.) O/B Switch set incorrectly
Heat, Cool or Fan Possible short in wiring, thermostat,
Runs Constantly heat, cool or fan system
Thermostat
Display & Thermostat display requires
Thermometer adjustment
Disagree
(Troubleshooting continued on next page)
6

TROUBLESHOOTING

breaker
door panel loose or not properly
installed
or system
or system
service or thermostat requires
replacement
item 20 and jumper wire
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
Verify thermostat and system wires are securely
attached.
Diagnostic: Set System Switch 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 after this charting.
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. Make sure
that menu item 20 and the jumper wire match.
Verify thermostat and system wires are securely
attached.
Diagnostic: Set System Switch 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 04