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TB6575/TB8575 DIGITAL FAN COIL THERMOSTATS
Symptom
Cooling does not turn
on (Cool On is solid in
the display).
Fan does not turn on
in a call for Heat.
Cannot select fan
speed.
Heating equipment is
running in the Cool
mode.
Heating equipment
does not turn off and
heat temperature
setting is set below
room temperature
(Heat On is not in the
display).
Cannot set the system
setting to Heat.
Cannot set the system
setting to Cool.
Heat On is not in the
display.
Cool On is not in the
display.
Remote sensor does
not display
temperatures
Remote Setback does
not activate
62-0311—05
Table 8. Troubleshooting. (Continued)
Possible Cause
Cooling equipment failure. For TB6575A/B:
Loose connection or
broken wire between
thermostat and cooling
equipment.
Wiring or connection
failure
Fan Control Type
selection is incorrect.
Incorrect System Type
configured.
Incorrect System Type
configured.
System Type (Installer
Setup code #2) is set to
Cool Only (value = 1).
System Type (Installer
Setup code #2) is set to
Heat Only (value = 0).
System Type setting is not
set to Heat and/or the
temperature setting is not
set above the room
temperature.
System Type setting is not
set to Cool and/or the
temperature setting is not
set below the room
temperature.
Incorrect ISU code.
Sensor is not compatible. The remote sensor must be TR21 or compatible 20K NTC.
Incorrect ISU code.
Remote setpoint error.
1. Check for 120/240 Vac at the equipment between power and
common, (terminals L and N).
2. Check for 120/240 Vac between the cool (Y) and common
(N) terminals. If 120/240 Vac is present, the thermostat is
functional.
For TB875A:
1. Check for 24 Vac at the equipment on the secondary side of
the transformer between power and common (terminals R
and C).
2. Check for 24 Vac between the cool terminal (Y) and trans-
former common. If 24 Vac is present, the thermostat is func-
tional.
If voltage is present, check the cooling equipment to find the cause
of the problem.
For TB6575A/B:
Check for 120/240 Vac between the cool (Y) and common (N)
terminals.
For TB875A:
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 thermostat and the cooling equipment.
Check wiring and make sure the connection is correct.
Check that the Installer Setup code #9 (Fan Control) value is set to
zero (0).
Check that the Installer Setup code #2 (System Type) value
matches the installed heating and/or cooling equipment.
Check that the Installer Setup code #2 (System Type) value
matches the installed heating and/or cooling equipment.
Set the Installer Setup code #2 value to match the installed heating
and/or cooling equipment.
Set the Installer Setup code #2 value to match the installed heating
and/or cooling equipment.
Set the Installer Setup code #2 to Heat and set the temperature
setting above the room temperature.
Set the Installer Setup code #2 to Cool and set the temperature
setting below the room temperature.
Set the Installer Setup code #4 to Remote (value = 1).
Make sure the NO/NC and timer selection is correct. Check the
value selected for ISU code #19.
Make sure the remote setback setpoint is correct for energy saving
usage.
18
Action
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