Thermistor Alarm; Fan Vfd Failure; Alarm Troubleshooting; Leaving Water Temperature Alarm - Carrier 09FC020 Installation, Start-Up And Maintenance Instructions

THERMISTOR ALARM

Thermistor out of range. Detects failed thermistor. Close alarm
contact, drive valves to bypass position, and disable fans.
Automatic reset.

FAN VFD FAILURE

This alarm detects a non-functioning VFD.
Manual reset.

Alarm Troubleshooting

LEAVING WATER TEMPERATURE ALARM

Alarm Criteria: Leaving water temperature is below the Low
Leaving Water Temp Alarm Limit or above the High Leaving Wa-
ter Temp Alarm Limit.
Action Taken by Controller: Alarm shown on display and alarm
output energized. For high water alarm, the valve will go to bypass
mode and the fan VFD will be disabled.
Reset Method: Automatic once temp is back in range.
Possible Causes: Bypass valve not functioning, Fans not function-
ing, Unit not enabled, Pump not on.

LEAVING WATER SENSOR FAILURE ALARM

Alarm Criteria: Sensor reading at controller is out of range.
Action Taken by Controller: Alarm shown on display and alarm
output energized.
Reset Method: Automatic once reading is back in range.
Possible Causes: Loose connection at controller, damaged sensor
wire, failed thermistor.

ENTERING WATER TEMPERATURE ALARM

Alarm Criteria: Entering water temperature is below the Low En-
tering Water Temp Alarm Limit or above the High Entering Water
Temp Alarm Limit.
Action Taken by Controller: Alarm shown on display and alarm
output energized.
Reset Method: Automatic once temp is back in range.
Possible Causes: Building return temperature beyond set limit.

ENTERING WATER SENSOR FAILURE ALARM

Alarm Criteria: Sensor reading at controller is out of range.
Action Taken by Controller: Alarm shown on display and alarm
output energized.
Reset Method: Automatic once reading is back in range.
Possible Causes: Loose connection at controller, damaged sensor
wire, failed thermistor.

OUTDOOR AIR TEMPERATURE ALARM

Alarm Criteria: Outdoor air temperature is below the Low Out-
door Air Temp Alarm Limit or above the High Outdoor Air Temp
Alarm Limit.
Action Taken by Controller: Alarm shown on display and alarm
output energized.
Reset Method: Automatic once temp is back in range.
Possible Causes: Air temperature beyond set limits.

OUTDOOR AIR SENSOR FAILURE ALARM

Alarm Criteria: Sensor reading at controller is out of range.
Action Taken by Controller: Alarm shown on display and alarm
output energized.
Reset Method: Automatic once reading is back in range.
Possible Causes: Loose connection at controller, damaged sensor
wire, failed thermistor.
FAN VFD FAILURE
Alarm Criteria: Fan VFD feedback signal not received at the con-
troller.
Action Taken by Controller: Alarm shown on display and alarm
output energized.
Reset Method: Automatic once contact closure is made.
Possible Causes: Wiring issue between fan VFD and controller.
Alarm at VFD. No power to VFD. VFD in Hand or Off position.

REVERSE LOAD WATER FLOW ALARM

Alarm Criteria: Entering water temperature is less than leaving
water temperature.
Action Taken by Controller: Alarm shown on display, alarm out-
put energized, valve will go to bypass mode, and the fan VFD will
be disabled.
Reset Method: Automatic once delta T is positive.
Possible Causes: 3-way valve not functioning, EWT and LWT
sensors swapped, damaged sensor wire, failed thermistor.
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