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Symptom
Display does not come
on.
Temperature settings do
not change.
not change
Heating or cooling does
.
not come on
Thermostat is calling for
Heat (Heat on) or Cool
(Cool on) but no heating
or cooling is running.
Heat does not turn on
(Heat On is solid in the
display).
Both the heating and cool-
ing equipment are run-
ning at the same time.
ning at the same time.
Cooling does not turn on
(Cool On is solid in the
display).
Fan does not turn on in a
call for heat (electric fur-
nace).
Table 7. Troubleshooting
Possible Cause
Thermostat is not being
powered.
The upper or lower tem-
perature limits were
reached.
The keypad is fully locked.
Thermostat minimum off−
time is activated.
System selection not set
to Heat or Cool.
System type Selection is
incorrect.
Heating or cooling equip-
ment is not operating.
Heating equipment failure.
Loose or broken wire con-
nection between thermo-
stat and heating equip-
ment.
The heating equipment is
not a heat pump but the
System Type (Installer
Setup Number 0170) is
set to Heat Pump.
Heating and cooling wires
are shorted together.
Cooling equipment failure.
Loose or broken wire con-
nection between thermo-
stat and cooling equip-
ment.
Fan Control in Heating is
set to Gas or Oil Furnace
(Setting 0180).
Page 11
Action
Check for 24 Vac between C and Rc.
Check that AAA batteries are installed correctly and are
good.
Check temperature setpoints.
Check Installer Setup Numbers 0600 and 0610; modify
as needed.
Check Installer Setup Number 0670 to change keypad
locked options.
Wait up to five minutes for the system to respond.
Set system Selection to correct position.
Check Installer Setup Number 0170 and make sure
correct System type is chosen.
Check wiring.
Check Installer Setup Number 0170 and make sure
correct system type is chosen.
Verify operation of equipment in System Test mode.
Check for 24Vac at the equipment on the secondary
side of the transformer between power and common. If
voltage is not present, check the heating equipment to
find the cause of the problem.
Check for 24 Vac between the heat terminal (W) and
transformer common. If 24 Vac is present, the thermo-
stat is functional. Check the heating equipment to find
the cause of the problem.
Check for 24 Vac between the heat terminal (W) and
transformer common. If voltage is not present, check
wire connection (loose or broken) between the thermo-
stat and the heating equipment.
Set System Type (Installer Setup Number 0170) to
match the installed heating and/or cooling equipment
Separate the shorted heating and cooling wires.
Check for 24 Vac at the equipment on the secondary
side of the transformer between power and common. If
voltage is not present, check the cooling equipment to
find the cause of the problem.
Check for 24 Vac between the cool terminal (Y) and
transformer common. If 24 Vac is present, the thermo-
stat is functional. Check the cooling equipment to find
the cause of the problem.
Check for 24 Vac between the cool terminal (Y) and
transformer common. If voltage is not present, check
the wire connection (loose or broken) between the ther-
mostat and the cooling equipment.
Set Fan Control in Heating to Electric Furnace (Setting
0180).
table continued on next page
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Table of Contents
Troubleshooting
