Fans constantly on

[G37xman]

I have a Pro 1500 S UPS. I've had it for 2 years. Since I first got it the fans are constantly running. I thought it was normal, but I see now it is not. It is very frustrating. I've tried to brain dead the UPS, but that changes nothing. I've disconnected and re connected the battery, the fans will not shut off. I need help. 

[Teken]

The unit comes with a three year hardware warranty as such you may consider submitting a RMA with APC Technical Support. Have ready the serial number, purchase receipt, and brief description of the problem / error codes if applicable.

Generally speaking at a high level there are three fan behaviours depending upon UPS Series, firmware, and environmental conditions present.

All enterprise Double Conversion (Online) Smart-UPS the fan runs continuously at a lower speed in normal operations and ramps up when a defined threshold have been met.

Line Interactive UPS depending upon Series and output class either have no fan or turn on when different conditions have been met which I’ll detail later below.

Back-UPS: The vast majority of Back-UPS do not incorporate a fan in the lower output class. Higher output systems incorporate a fan and generally speaking the internal fan will come on when the following conditions are present:

Charging, Inverting, High Load, High Temperature, Power Loss.

As such you should review and provide the following logs here and to APC Technical Support from Power Chute: Event, Data, UPS, Diagnostics.

The vast majority of times the internal fan is on because the physical location lacks proper spacing and cooling. Other times it’s because the unit is subjected to external heat from the sun, HVAC, equipment.

The remaining conditions are due to high output load or the system is inverting (AVR) for extended periods due to dirty power.

NOTE: There are specific instances where a Back-UPS Series units fan runs continuously at a lower speed and this is by design. As such there is no problem as this is intended by the manufacturer.

You will find this behaviour even in the exact same model. The only difference is the firmware installed in the system! 🤦‍♂️

You can test if it’s by designed by simply removing the power. If the fan increases in speed at some point especially during charging than it’s by design.

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