Section 7. Troubleshooting - Trane TZONE950AC52ZA Installation Manual

Section 7. Troubleshooting

Symptom
Thermostat displays an alert
code on the screen.
Display will not come on
Indoor temperature display is
incorrect.
Indoor humidity display is incor-
rect.
Room temperature overshoots
when the Heat/Cool setting is
changed more than 2°.
Heating will not come on.
Cooling will not come on.
Heating or Cooling is displayed,
but no warm or cool air is coming
from the registers.
Fan runs all the time
Fan is set to ON but not running.
Cooling or Heating cycles too
fast or too slow (narrow or wide
temperature swings).
Heat pump is not turning on; only
furnace or electric heat strips are
running.
Cannot change system mode to
desired setting.
Screen does not respond prop-
erly to a button press
"No System Found" displayed on
the thermostat
Slow or no response to any but-
ton presses
18-HD64D1-1
Possible Causes
Alert Code is present.
Loss of 24VAC between R & B at the thermo-
stat.
Indoor temperature display needs calibration.
Indoor humidity display needs calibration.
1) Oversized heating/cooling equipment under
current conditions. Control cannot respond fast
enough to prevent overshooting.
2) Improper location of thermostat.
3) Aggressive recovery is activated.
1) System mode is not set to heat/Auto or set-
point is set too low.
2) Minimum off time delay is being enforced.
3) Heating system may require service.
1) System mode is not set to cool/Auto or the
setpoint is too high.
2) Minimum off time delay is being enforced.
3) Cooling system may require service.
1) There is a fan delay as the heating or cooling
equipment turns on.
2) Equipment is not working properly.
1) Fan mode is set to On, Circulate or Clean
mode
2) There is a failure in the indoor unit
1) Humidity control is engaged.
2) Blower motor is not functioning.
1) Check the location of the thermostat for
drafts.
2) Cycles per hour or aggressive recovery is
improperly set.
1) Outdoor temperature is below compressor
lockout temperature setting.
2) Compressor heating lockout is enabled and
outdoor temp sensor is out of calibration or
failed.
Equipment is not configured properly.
Screen is out of calibration
Internal error
Internal error
Action
Refer to the Alert Code Addendum. Check the
Alert icons in the diagnostic screen.
1) Check wiring between R & B to see if R & D, or
B & D have been reversed.
2) Check transformer for 24VAC output.
3) Check for broken or shorted thermostat wire.
Calibrate temperature sensor from thermostat
menu.
Calibrate humidity sensor from the thermostat
menu.
1) Compare heat load calculation to equipment
chosen.
2) Relocate thermostat (or use remote sensor) if
thermostat is in "dead" spot (poor or no air circula-
tion).
3) Deactivate aggressive recovery.
1) Set mode to heat and raise the setpoint above
the room temperature.
2) Wait for 5 minutes and recheck heating equip-
ment.
3) Check/repair system.
1) Set mode to cool and lower the setpoint below
the room temperature.
2) Wait for 5 minutes and recheck cooling equip-
ment.
3) Check/repair system.
1) Wait a minute for blower delays and recheck
registers.
2) Check/repair system.
1) Check thermostat settings to see if fan is set to
On, Circulate or Clean mode.
2) Check indoor unit for failures (such as tripped
heating limit).
1) If indoor humidity is higher than desired set-
point, the blower will cycle off with the equipment.
2) Check/repair system.
1) Seal all air leaks behind thermostat. Relocate
thermostat or apply remote indoor temperature
sensor.
2) Adjust cycle rates and aggressive recovery
features in the advanced installer set up.
1) Check/repair outdoor sensor or wiring.
2) Adjust the compressor lockout temperature
setting if desired.
Check the standard installer set up screen to
ensure equipment is properly configured.
Remove thermostat from sub base and reset.
Follow the calibration instructions when the ther-
mostat reboots.
Reboot the thermostat via onscreen button.
Remove the thermostat from the sub base and
reset.
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