Problem with ES500

[Anonymous user]

My 2+ year old ES500 was working fine until today when the relay started to switch on and off erratically. I powered it off and left it for a few hours. When I tried to powered it on again, it started to beep 4 times every 30 secs even though there is AC power. During the beeping, the Power-ON LED would be off. From diagnostic, this seemed to imply that the UPS is supplying battery to the load but it should not be the case when it is on AC power is available. I confirmed that the AC power is available and have tested the UPS at various AC outlet around my house. All my testing is yielding the same result. Can you explain why my UPS fail to switch to AC power when it is available ?

[Techie_apc]

John,

If the UPS's input breaker is tripped, then the input power will not pass through the circuit. Try resetting the circuit breaker which is located near the UPS input power cord and then check if the unit works off AC power.

[Anonymous user]

I checked the circuit and noted that the input circuit breaker only control the "Surge Protection" outlet. The other 3 outlet powered by the battery is not control by the input circuit breaker so I am not surprise that there was not effect when I reset the circuit breaker. Any idea what else can I do ?

[Techie_apc · Accepted solution]

hmm..the UPS should work online if the input power is normal. If you have Power Chute software installed on your Computer to monitor the UPS, then please check the input power quality. And also adjust the UPS sensitivity to Low through Power Chute Personal Edition software and check if that helps. If the UPS does not work online even though the input power is normal, then there should be an issue with the UPS internal circuitry.