The device isn't "seeing" a good AC input. This could be, most likely, for one of three reasons. The plug isn't good (and not supplying AC, or the plug is wired backwards), also, the cord could be bad (same thing, no AC), or the device, for some reason, is faulty, internally. Try plugging it in to another outlet and see what you get. If you still get the message, the problem is either a bad cord or unit. If the unit's still under warranty, I would have it checked out that way. Otherwise, the unit will have to be serviced, and that can be a bothersome experience, plus costly. If you do choose to have it looked at, make sure you get an estimate first, since repair can often be more than the new replacement cost. Since both parties (electrician and pool man) are tending to think it's the other's mistake, I'm thinking the unit is possibly bad. As an afterthought, most AC control systems use relays to drop the line power. There is a chance that the relay's contacts are corroded or oxidized, and not making good contact, thus not providing the AC input across the relay. If you can get to the relay, often you can take the cover off and clean the contacts with a very fine emory cloth, and electrical contact cleaner. Good luck, and hope this helps

Hello,

truly, its an electrician error, or error from the unit itself. According to the error code ("check AC line"), there is something wrong with the connection of your electrician, maybe he did not do the connections properly. There is something wrong about his connection that is prompting the error.

You can also check the electricity entering into the unit. Maybe the voltage is to high or too low.

Also, did you just buy the unit? If the electricians connection he correct has he claimed, then the unit itself need to be check. I believe the electrician should help out with this, or you can call another electrician.

Take care.