Honeywell DELUXEHEATPUMP T8511G Installation Instructions Manual page 9

Symptom
Heating will not No power to the thermostat.
come on.
Thermostat minimum off time
is activated.
System selection is not set to
Heat.
Cooling will not No power to the thermostat.
come on.
Thermostat minimum off time is
activated.
System selection is not set to
Cool.
System on indicator Heating equipment is not
(flame=heat, operating.
snowflake=cool) is
displayed, but no
warm or cool air is
coming from the
registers.
System on indicator Option not activated.
is not displayed,
but heating or
cooling system is
operating
Outdoor Option not activated.
temperature
a
not displayed
Outdoor sensor is connected
Outdoor
incorrectly.
temperature
a
display is incorrect
Wrong sensor.
a
Available on select models.
Troubleshooting Guide (Continued).
Possible Cause
T8511G DELUXE HEAT PUMP ZONE THERMOSTAT
• Check that C terminal is connected to the system
transformer.
• Check for 24 Vac between C and R and between R and Y1
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 system switch at the equipment is in
the Off position—set to On position.
— check wiring between thermostat and HVAC
equipment—replace any broken wires and tighten
any loose connections.
— If 24 Vac is present, proceed with troubleshooting.
Wait up to five minutes for the system to respond.
Set system selection to Heat.
• Check that C terminal is connected to the system
transformer.
• Check for 24 Vac between C and R and between R and Y1
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 system switch at the equipment is in
the Off position—set to the On position.
— check wiring between thermostat and HVAC
equipment—replace any broken wires and tighten
any loose connections.
— If 24 Vac is present, proceed with troubleshooting.
• Wait up to five minutes for the system to respond.
• Enter Installer Setup number 33. Reconfigure minimum off
time (if required).
Set system selection to Cool.
Verify operation of heating equipment in self-test.
Enter Installer Setup number 36 and reconfigure to 00.
Enter Installer Setup number 24 and set to 01. Thermostat
must have OT terminals and a C7089B1000 installed.
Refer to C7089B1000 installation instructions and check wiring
between the thermostat and sensor.
Replace sensor with C7089B1000 sensor.
9
Action
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