Maruson TAC-LV1K, User Manual

Maruson | Tacoma 1KVA-3KVA User Manual 

26 

EPO 

EPO function is 
active.   

Connect the EPO switch to disable this function and ensure the 
connection is secure. If connected to EPO cable, check if EPO 
cable needs to be replaced. Replace with one no more than 
350 feet or has a resistance greater than 10 ohms.     

bLOW 

Batteries 
disconnected. 

Check the battery connections are properly connected.   

End of battery 
lifespan. 

Replace the batteries with the same type and quantity. All 
batteries should be replaced at the same time. 

HIGH 

Battery over 
voltage or 
charger failed. 

Check the charger output, battery input. 

5.2.

LCD FAULT CODE 

Fault Code  Possible Cause  Action 

SHOR 

Output short 
circuit occurred 

Remove all equipment. Turn off the UPS. Check whether the 
output of UPS and equipment have short circuited. Make sure 
the short circuit is removed, and the UPS has no internal 
faults before turning on again. 

INVL 

Internal voltage 
too low.   

Internal fault. Contact your local authorized dealer or 
Maruson. 

INVH 

Inverter voltage 
too high. 

Inverter voltage is too high. Contact your local authorized 
dealer or Maruson. 

ISFT 

Inverter failed. 

Internal fault. Contact your local authorized dealer or 
Maruson. 

OVLd 

Overload 

Remove non-critical loads until total capacity is within UPS 
capacity range. 

OVTP 

Internal 
temperature too 
high. 

Check whether the UPS is overloaded, the air vents are 
blocked, a fan has failed, or if the ambient temperature is over 
104



F / 40



C. Remove any restrictions around the UPS. Clear 

the vents and remove any equipment that is causing an 
overload. Allow the UPS to cool down for at least 15 minutes 
before restarting the UPS.   

bUSH 

Bus voltage too 
high. 

Internal fault. Contact your local authorized dealer or 
Maruson. 

bSFT 

Internal fault. 

Contact your local authorized dealer or Maruson. 

Note:

 When the UPS fails, the Fault/Warning icon will appear on the LCD and 

backlight will change to red while the alarm beeps continuously.   

Note: 

When the UPS detects a fault, it will stop the power conversion of mains 

and battery. 

5.3.

ADDITIONAL TROUBLESHOOTING CONDITIONS 

Condition 

Possible Cause 

Action 

UPS not supplying 
power to connected 
equipment 

UPS is in Standby 
Mode. 

Change UPS to Line Mode.   

EPO switch is open. 

Check the back of the UPS EPO tab to 
ensure it is securely in place. If this is