5.1.7  Overheating inside the STP control unit 
The temperature in the STP control unit increases when the ventilating duct is blocked or the ambient 
temperature is high. The LCD displays error message "CAUTION: CNT heat*" when the inside of the 
STP control unit overheats. In this case, the pump does not stop. 
When the STP control unit overheats continuously, the STP pump decelerates and stops. 
The "FAILURE" LED illuminates and the LCD displays error message "CNT Overheat *" or 
"CONTROLLER OT" (SCU-350 series).  
 
5.1.8  Overspeed 
When the rotational speed of the STP pump exceeds the specified rotational value due to a failure in 
the motor driver, the MAIN POWER on the STP control unit switches "OFF". The STP pump has no 
power supplied, decelerates and stops. 
The "FAILURE" LED illuminates and the LCD displays error message "Overspeed *" or 
"OVERSPEED"/ "DRIVER RA" (SCU-350 series). 
 
5.1.9  Abnormality/Error in the TMS unit (for use with the TMS unit) 
If the temperature of the STP pump base unit is higher than the setting value by 10 °C (18 °F) or 
more due to the occurrence of an abnormality/error in the TMS heater or other fault, the "FAILURE" 
LED illuminates and the LCD displays error message "TMS Higher Temp". The heater is switched 
OFF and the TMS valve is operated. Continue to operate the TMS valve while "TMS Higher Temp" is 
displayed after the pump stops. 
If the temperature of the STP pump base unit is lower than the setting value by 10 °C (18 °F) or more 
due to the occurrence of an abnormality/error in the TMS heater or other fault, the "FAILURE" LED 
illuminates and the LCD displays the error message "TMS Lower Temp". The heater and the TMS 
valve are switched OFF and the STP pump decelerates and stops. 
Note:  "TMS Lower Temp" is not detected for a certain time when the STP pump starts. 
When an abnormality/error occurs in the TMS connection cable, the STP pump decelerates and 
stops. The heater and the TMS valve are switched OFF. The "FAILURE" LED illuminates and the 
LCD displays the error message "T.Cable Disconnected". 
 
5.1.10  Failure of the air-cooling fan (for SCU-800/801, SCU-1600/1601) 
When the air-cooling fan in the STP control unit locks and stops, the "FAILURE" LED illuminates and 
the LCD displays error message "Driver Failure" and "Driver Fan Failure". The STP pump 
decelerates and stops. 
Note:  Refer to the STP Control Unit Instruction Manual (C) for other error messages.