69-1074
11
T8624D CHRONOTHERM
®
IV DELUXE ZONE MULTISTAGE THERMOSTAT
Troubleshooting Guide (Continued).
a
Select models.
Symptom
Possible Cause
Action
Temperature
settings will not
change. (Example:
Cannot set the
The upper or lower
temperature limits were
reached.
Check the temperature setpoints:
•
Heating limits are 40 to 90°F (7 to 31°C)
•
Cooling limits are 45 to 99°F (9 to 37°C).
heating higher or
the cooling lower.)
The setpoint temperature
range stops were
configured.
Check Installer Setup numbers 34 and 35 and reconfigure the
setpoint stops.
Heating will not
come on.
No power to the
thermostat.
•
Check for 24 Vac between R and C terminals.
—
If missing 24 Vac:
—
check if the circuit breaker is tripped—reset the
circuit breaker.
—
check if the system fuse is blown—replace the fuse.
—
check if the power switch on the HVAC equipment is in
the Off position—set to the On position.
—
check wiring between thermostat and zone control
panel—replace any broken wires and tighten
any loose connections.
—
If 24 Vac is present, proceed with troubleshooting.
Heating will not
come on.
Thermostat minimum off time
is activated.
Wait up to five minutes for the system to respond.
System selection is not set
to Heat.
Set system selection to Heat.
Heating setpoint is below
room temperature.
Check heating setpoint. Set heating setpoint to desired
temperature.
Cooling will not
come on.
No power to the
thermostat.
•
Check for 24 Vac between R and C.
—
If missing 24 Vac:
—
check if the circuit breaker is tripped—reset the
circuit breaker.
—
check if the system fuse is blown—replace the fuse.
—
check if the power switch on the HVAC equipment is in
the Off position—set to the On position.
—
check wiring between thermostat and zone control
panel—replace any broken wires and tighten
any loose connections.
—
If 24 Vac is present, proceed with troubleshooting.
Thermostat minimum off time
is activated.
•
Wait up to five minutes for the system to respond.
•
Enter Installer Setup number 33. Reconfigure minimum off
time (if required).
System selection is not set
to Cool.
Set system selection to Cool.
Cool setpoint is above
room temperature.
Check cooling setpoint. Set cooling setpoint to desired
temperature.
System on indi-
cator (flame=heat,
snowflake=cool) is
displayed, but no
warm or cool air is
coming from the
registers.
Heating or cooling
equipment is not
operating.
Verify operation of heating or cooling equipment in self-test.
Outdoor tempera-
ture not displayed
a
Option not activated.
Enter Installer Setup number 24 and set to 1. Thermostat must
have OT terminals and a C7089B1000 installed.
Outdoor
temperature
Outdoor sensor is
connected incorrectly.
Refer to C7089B1000 installation instructions and check wiring
between the thermostat and sensor.
display is
incorrect
a
Wrong sensor.
Replace sensor with C7089B1000 sensor.
