Inverter Problem "Freedom 458 Combi"

[Rick Daniels]

                Over the past few years I have had only minor issues with the electrical system in my coach but resolved them all with little effort, often with the help of this forum and it's many learned contributors.  Now I am stumped and must reach out for help.  In preparing for a road trip I glanced at the remote inverter/charger panel in the coach and noticed that the "AC in" led was blinking green and the "fault" led was solid on red.  Never seen that before.  Checked the front panel of the inverter itself and observed two led's blinking red. One labeled overtemp/overload, the other labeled low battery.  The remote panel in the coach showed battery state fully charged and indicated 13.0 volts.  I was in storage with a 30amp shore power.
      In checking the manual on the inverter I found no code for just the two blinking red led's.  The only fault with two fast blinking red led's also has a blinking green led. No blinking green. It did however reference (absent the blinking green) a backfeed and incorrect wiring fault. In checking the manual on the remote panel the above described led's indicate "AC backfeed (external AC power detected at inverter output". "Disconnect incoming AC power and correct wiring".
     All the while, the cooling fan on the inverter is running and even runs when AC power is cut off.  Also all electric lights, outlets and appliances work properly.  I cut the AC power to the coach as suggested and now I have no idea where to go to correct the wiring.  As you probably surmise, I need help so any suggestions will be more than welcome.  Thanks in advance. 

[Steve Huber Co-Admin]

Rick,
Suggest you disconnect the batteries for about 5 minutes, then re-connect and apply power to inverter. This should force the inverter to reset. Also check the shore power for for proper wiring (but if it worked previously should be OK. Same for coach wiring).
Steve

[Rick Daniels]

Well Steve Huber I cut shore power, cut battery power and waited five minutes and re-connected battery power and the inverter did re-set.  Both the remote panel and the inverter itself showed no fault codes.  I then applied shore power and the inverter went into fault mode right away.  I repeated the process and used generator power instead of shore power with same results-----instant fault codes.  The fault codes at the inverter hint at incorrect ac wiring.  AC wiring hasn't changed.  The fault codes at the remote panel also state "AC Back feed, external ac power detected at inverter output".  I thought that external ac power at inverter output was normal when hooked up to shore power or genset power.  Checked all connections into and out of inverter and all seem secure.  Checked all connections in inverter ac sub pan and all seem ok.  Totally baffled.  Far as I can tell, everything works normally even when the inverter is in fault mode.

[Fred Brooks]

    Rick,
I think your issue may be internal. Somehow the unit is detecting the output voltage is being fed back into the unit on the input side. If the wiring hasn't changed, the only place that could take place is inside the unit. To prove if that is the case, turn off the circuit breakers in the sub-panel located on the ceiling of #4 compartment on the passenger side. (this is the sub-panel that supplies 120 volt power to the microwave, front & rear tv, and the outlets in the kitchen and bathroom. If it still shows the same fault, you have isolated all of the outputs. Hope this helps, Fred

[Rick Daniels]

Problem solved . Yea.  Followed the advice of Fred and Steve. With shore power and battery power off, I unwired to two 120vac output lines from the inverter.  Checked all the connections and breakers in the inverter sub-panel making sure they were all tight and secure.  Restored shore and battery power and checked the output voltage on the two output wires that fed the subpanel and both showed 120vac and no fault  codes appeared.  With the breakers off in the sub-panel, I reconnected the the inverter output lines to the subpanel with no fault codes.  Turn on the subpanel breakers one at a time, no fault codes.  Everything is now working just fine, thank you.  Conclusion-----one, or more, of the several connections in and between the inverter and subpanel had, over time, become loose enough to create the back feed fault code.  Cant tell you which one but they are all tight now and I'm back in business.  Thank you, thank you, thank you.