Fixing an ABB/Solar One Aurora Uno inverter with Int. Error E031

Our Power One Uno with the fatal "Error! Int. Error E031"

A couple of days ago our ABB/Power One Aurora Uno inverter stopped working. It starts up, clicks relays and display "Error! Int.Error   E031". Nothing more happens. It's six years old, so just out of the five year manufacturer's guarantee period. Not a good sign.

Searching on the internet suggests that this is a very common fault and people claim it's a faulty relay. However, no-one seemed to be offering advice on how to fit the fault.

I didn't want to replace the entire inverter. A repair is preferred because the whole reason to have a solar energy system is to conserve resources. Throwing out a huge device like this because of a minor fault goes completely against our reasoning for installing the product in the first place.

ABB offered absolutely no help at all. Their reply to me was useless even to the extent of not bothering to get my name right: their swiftly cut and pasted reply to say "we won't help at all" was addressed to someone called "Emmanuel".

The company which installed the inverter in the first place did offer a reasonable price for a replacement (from a different manufacturer and with a ten year guarantee) but that would cost us €1000 and of course it would still mean throwing out a mostly good existing unit. It turns out that the failed part is nothing more than a €5 relay on one of the printed circuit boards within the inverter.

Discolouration about the relay shows that it's failed.

The other side of the PCB has a crater in it from the pin on the relay melting/burning away.

Anyway, long story cut short, if you want to know how to repair one of these inverters click on the following line:

I've repaired my inverter and it now works perfectly again

Hopefully the repair will be good for another five years. If I find myself buying a replacement inverter in a few years time, it won't be bought from ABB as their customer service is absolutely useless.