Section 7. Troubleshooting - Trane 18-HD64D1-4 Installation Manual

Section 7. Troubleshooting

Symptom
Control 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 Control
18-HD64D1-4
Possible Causes
A critical or major alert is present.
Loss of 24VAC between R & B at the Control.
1) Indoor temperature display needs calibration.
2) Heat from touch screen is being trapped
within the thermostat body. See section 3.1 for
mounting location guidelines.
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 Control.
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 Control 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.
3) The outdoor unit is not reporting (Err.126.00)
Equipment is not configured properly.
1) Screen is out of calibration.
2) Internal Control fault
Internal error
Action
Navigate to the Diagnostic screen on the 950
Control for a Problem Description and Possible
Cause.
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.
1) Calibrate temperature sensor from Control
menu.
2) Move thermostat away from competing air
stream or use a remote temperature sensor
Calibrate humidity sensor from the Control menu.
1) Compare heat load calculation to equipment
chosen.
2) Relocate Control (or use remote sensor) if Con-
trol is in "dead" spot (poor or no air circulation).
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 Control 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.
A humidity icon will be displayed on the Fan Mode
button when the blower operation is being inhib-
ited due too high humidity.
2) Check/repair system.
1) Seal air leaks behind Control. Relocate Control
or apply remote indoor temperature sensor.
2) Adjust cycle rates and aggressive recovery
features in the advanced installer set up.
1) Adjust the compressor lockout temperature
setting if desired.
2) Check/repair outdoor sensor or wiring.
3) Check communication status of outdoor unit.
Check the standard installer set up screen to
ensure equipment is properly configured.
1) Remove Control from sub base and reset.
Follow the calibration instructions when the
Control reboots.
2) Remove Control from sub base and reset.
Reboot the Control via onscreen button.
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