Sensor Detection And Fault Detection; Troubleshooting - Johnson Controls FCP-NA-701-L User Manual

Sensor detection and fault detection

The FCP thermostat detects the remote temperature sensor and pipe temperature sensor during
the thermostat power-up and run-time. The pre-configuration profile defines whether the remote
and pipe sensors are required in the system or not.
If the remote temperature sensor is installed, then the remote temperature sensor reading is used
instead of the internal temperature sensor.
If the on-board sensor stops to function correctly, the sensor error flashes on the display. All
heating and cooling outputs go to off until the sensor value is back in normal working range.
If the remote sensor stops to function correctly or is removed, the remote sensor error flashes
on the display. All heating and cooling outputs go to off until the sensor value is back in working
range. The thermostat does not switch back to use the on-board sensor automatically. Check and
reinstall the remote sensor correctly in order to resume the thermostat to operate.
If the pipe sensor stops to function correctly or is removed, the pipe sensor error flashes on the
display. All heating and cooling outputs go to off until the sensor value is back in working range.
This applies to the 2-pipe FCU system only.
You can recover the remote sensor and pipe sensor from error state under the following
operations:
• Power cycle the thermostat
• After you enter and exit the installer setting menu

Troubleshooting

The following tables are placeholders and examples of troubleshooting information that could
potentially be included.
Table 9: Fault list
Error code
ER:01
ER:02
ER:03
ER:04
24
Description
ERROR_AIR_SENSOR_OPEN
ERROR_AIR_SENSOR_SHORT
ERROR_AIR_SENSOR_HI
ERROR_AIR_SENSOR_LO
FCP Non-Programmable and Programmable Fan Coil or PTAC Thermostat Largo User Guide
Solutions
• Check if the built-in temperature sensor is
disconnected from the thermostat circuit
board or damaged.
• Contact technical support.
• Check if the built-in temperature sensor is
short circuited or damaged.
• Contact technical support.
Built-in temperature sensor detected a too high
temperature.
• Check if the thermostat wiring is connected
correctly to the FCU or PTAC.
• Contact technical support.
Built-in temperature sensor detected a too low
temperature.
• Check if the thermostat wiring is connected
correctly to the FCU or PTAC.
• Contact technical support.