Installation manual
InRow RD Operation and Maintenance46
Troubleshooting
Problem  Possible Cause Corrective Action
Controls erratic or 
inoperative
• Inlet temperature to cooling 
unit is higher than rated 
maximum temperature
• Reduce the load or add additional cooling equipment.
Fans fail to start • Cooling unit shutdown due 
to an external command
• Temporarily remove the input contact cable, if it is 
connected.
• Single fan fails to start • Verify that the farn circuit breaker is ON.
Cooling unit cannot 
obtain setpoint
• Improper placement of 
remote temperature sensor
• Verify that the remote temperature sensor is properly 
located in the cold aisle.
• Dirty filter • Clean the filter.
• Dirty coil • Clean the coil.
• Application error • Contact APC at a number located on the rear of this 
manual.
• Heat load is too far away • Place the cooling unit closer to the heat load.
Water carryover • Improper fan speed selected  • RACS and HACS modes only: Select the next-highest fan 
speed setting. For example, change the fan speed setting 
from Low to Med/Low.
• Room humidity is too 
high/low
• Improve room sealing.
Temperature control 
not tight enough
• Improper placement of 
remote temperature sensor
• Verify that the remote temperature sensor is properly 
located in the cold aisle.
Water on outside of 
cooling unit
• Condensate drain hose is not 
connected or not properly 
routed outside the cooling 
unit
• Verify that the condensate drain hose is properly connected 
to the pump and properly routed outside of the cooling unit.
• Verify that the condensate drain line does not exceed 3.5 m 
(11.5 ft) lift and 18.0 m (60.0 ft) horizontal run.
• Leak in drain system • Locate and repair the leak.
• Cooling unit not leveled 
properly
• Adjust the leveling feet of the cooling unit.
• Damaged piping insulation • Identify damaged area and repair the insulation.
Display interface 
not operational, but 
cooling unit 
operates
• Display interface not 
connected properly
• Verify that the display interface cable is connected properly.
Incorrect air 
pressure
• False filter clogs • Verify that the ends of the clear plastic air tubes are not 
obstructed.
• Verify that the clear plastic air tubes are connected to the 
controller.
• Verify that the clear plastic air tubes are not pinched.










