Step 7. Troubleshooting - Honeywell T7350 System Engineering

T7350 COMMERCIAL PROGRAMMABLE THERMOSTAT

Step 7. Troubleshooting

Symptom
Display will not Thermostat is not being powered.
come on.
Temperature Room temperature display has been
display is recalibrated.
incorrect.
Thermostat is configured for °F or °C
display.
Bad thermostat location.
Display shows three dashes and a
degree sign (all systems shut down).
Temperature Upper or lower temperature limits
settings will not were reached.
change.
(Example: Cannot
Occupied setpoint temperature
set heating higher
range stops were configured.
or cooling lower.)
Keypad is locked. When a locked
key is pressed, LOCKED appears
momentarily on the LCD.
Room Remote temperature sensing is not
temperature is out working.
of control.
Heat will not come No power to the thermostat.
on.
Thermostat minimum off time is
activated.
System selection is set to Off or
Cool.
63-4368
Table 11. Troubleshooting Information.
Possible Cause
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.
Use PDA or L S ™ configuration software to recalibrate as
ON PEC
desired.
Press both Run Schedule and Copy, then reconfigure the display.
Relocate the thermostat.
T7350 is set for remote sensing and sensor is missing or circuit is
either open or shorted.
Check the temperature setpoints:
• Heating limits are 40 to 90°F (7 to 31°C)
• Cooling limits are 45 to 99°F (9 to 37°C)
Using a PDA or L S ™, check setpoint stops. If necessary,
ON PEC
reconfigure the stop(s).
• Use PDA or L S ™ (Set, Display) to unlock keypad.
ON PEC
• Press both Run Schedule and Copy, then change keypad lock
level.
Check all remote sensors.
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.
• Wait up to five minutes for the system to respond.
• Use PDA or L S ™ to configure heating response.
ON PEC
Set system selection to Heat or Auto.
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Action