STS11 Touchscreen Programmable Thermostat
86
TROUBLESHOOTING (TABLE 10)
Table 10. Troubleshooting.
Symptom Possible
Cause Action
Display does not come on.
Thermostat is not being powered.
Check for 24VAC between C and RC.
Check that AA batteries are installed
correctly and are good.
The upper or lower temperature limits
were reached.
Check temperature set-points.
Check Installer Setup Numbers 0600 and
0610; modify as needed.
Temperature settings do not change.
The keypad is fully locked.
Check Installer Setup Number 0670 to
change keypad locked options.
Thermostat minimum off-time is
activated.
Wait up to five minutes for the system to
respond.
System selection is not set to Heat or
Cool.
Set system Selection to correct position.
Heating or cooling does not come on.
System type Selection is incorrect.
Check Installer Setup Number 0170 and
make sure correct System type is
chosen.
Thermostat is calling for Heat (Heat on)
or Cool (Cool on) but no heating or
cooling is running.
Heating or cooling equipment is not
operating.
Check wiring.
Check Installer Setup Number 0170 and
make sure correct system type is
chosen.
Verify operation of equipment in System
Test mode.
Table 10. Troubleshooting. (CONTINUED)
Symptom Possible
Cause Action
Heating equipment failure.
Check for 24VAC at the equipment on
the secondary side of the transformer
between power and common. If voltage
is not present, check the heating
equipment to find the cause of the
problem.
Check for 24VAC between the heat
terminal (W) and transformer common. If
24VAC is present, the thermostat is
functional. Check the heating equipment
to find the cause of the problem.
Heat does not turn on (Heat On is solid in
the display).
Loose or broken wire connection
between thermostat and heating
equipment.
Check for 24VAC between the heat
terminal (W) and transformer common. If
voltage is not present, check wire
connection (loose or broken) between
the thermostat and the heating
equipment.
Cooling does not turn on (Cool
On is solid in the display)
Cooling equipment failure.
Check for 24VAC at the equipment on
the secondary side of the transformer
between power and common. If voltage
is not present, check the cooling
equipment to find the cause of the
problem.
Check for 24VAC between the cool
terminal (Y) and transformer common. If
24VAC is present, the thermostat is
functional. Check the cooling equipment
to find the cause of the problem.
STS11 Touchscreen Programmable Thermostat
87