BR1200 AVR boost unstoppable

[BillP]

This question was originally posted by Michele on APC forums on 7/30/2015

---

In the last month I've had several undervoltage events at home, and that is giving troubles to my ups.

Input voltage should be 230V, but during this summer it's floating around 200-220V

This is what happens:

- input voltage stable around 205-210, ups stays quiet and doesn't work at all

- input voltage drops to 190 or less

- ups kicks in

- avr boost on

- input voltage slowly rise again to 205-210 but avr boost remains in function, I can ear the sound coming from the ups.

Even though the voltage rise to decent values the avr boost doesn't stop itself, there's no way to shut down this thing. After few hours I decide to turn off/on the entire unit and the avr boost is gone.

Is it intended or the ups is not working as it should? Hysteresis? or something broken?

Warranty is over, is there any diagnostic or reset procedure I can try?

I've tried changing the sensitivity but that doesn't help, it's doing the same.

[BillP]

This reply was originally posted by Jordan on APC forums on 7/30/2015

---

Michele,

There is a hysteresis factor in regards to AVR so that the AVR does not trip on and off rapidly due to strange voltage flucuations.  This is normal behavior.

Regards,

[BillP · Accepted solution]

This reply was originally posted by Michele on APC forums on 7/30/2015

---

ok, so if it's this hysteresis what 's waiting for to stop avr boost?

that input voltage rises to "X" Volts? 

3 hours have passed, in the meantime input voltage has slowly rised to 212-213V stable and the avr boost it's still on, non stop.

Let's see this night if it will stop when input goes up to 220V, in that case I assume it's not hysteresis anymore, but a fault.

If only I could find some numbers to understand better how this hysteresis works