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T7351 COMMERCIAL PROGRAMMABLE THERMOSTAT
63-2666—03 18
Table 10. Hot Gas Bypass Dehumidification Logic. Auxiliary output during call for multiple cooling stages for two
reasons:
1. This method assumes that the cooling provides
dehumidification.
2. Multiple cooling stages probably provide necessary
dehumidification.
NOTE: Hysteresis and a minimum timer prevent short
cycling of this output.
TROUBLESHOOTING GUIDE (TABLE 11)
Humidity Cooling Stages Active Auxiliary Output
High more than one De-energized
High one or less Energized
Low more than one De-energized
Low one or less De-energized
Table 11. Troubleshooting Information.
Symptom Possible Cause Action
Display will not
come on.
Thermostat is not being powered. Check that X terminal is connected to the system
transformer.
Check for 24 Vac between X and RH or RC terminals.
If missing 24 Vac:
• Check if circuit breaker is tripped; if so, reset circuit
breaker.
• Check if system fuse is blown; if so, replace fuse.
• Check if the HVAC equipment power switch is in the Off
position; if so, set to the On position.
• Check wiring between thermostat and HVAC equipment.
Replace broken wires and tighten loose connections.
If 24 Vac is present, proceed with troubleshooting.
Temperature
display is incorrect.
Thermostat is configured for ° F or ° C display. Press both Run Schedule and Copy, then reconfigure the
display.
Bad thermostat location. Relocate the thermostat.
Display shows three dashes and a degree sign
(all systems shut down).
T7351 is set for the remote sensing and sensor is missing or
circuit is either open or shorted.
Temperature
settings will not
change.
(Example: Cannot
set heating higher
or cooling lower.)
Upper or lower temperature limits were
reached.
Check the temperature setpoints:
• Heating limits are 40° to 90° F (4° to 32° C)
• Cooling limits are 45° to 99° F (7° to 37° C)
Occupied setpoint temperature range stops
were configured.
Check setpoint stops. If necessary, reconfigure the stop(s).
Keypad is locked. When a locked key is
pressed, LOCKED appears momentarily on the
LCD.
Change keypad lock level.
Room temperature
is out of control.
Remote temperature sensing is not working. Check all remote sensors.
Heat will not come
on.
No power to the thermostat. Check that X terminal is connected to the system
transformer.
Check for 24 Vac between X and RH terminals.
If missing 24 Vac:
• Check if circuit breaker is tripped; if so, reset circuit
breaker.
• Check if system fuse is blown; if so, replace fuse.
• Check if the HVAC equipment power switch is in the Off
position; if so, set to the On position.
• Check wiring between thermostat and HVAC equipment.
Replace broken wires and tighten loose connections.
If 24 Vac is present, proceed with troubleshooting.
Thermostat minimum off time is activated. • Wait up to five minutes for the system to respond.
• Configure heating response.
System selection is set to Off or Cool. Set system selection to Heat or Auto.
DAT high limit has been reached, or
OAT lockout is engaged.
• If the setpoints are correct, do nothing.
• Adjust or disable DAT high limit and/or OAT lockout.
• Check HVAC equipment to ensure proper operation.