If you intend to rent it out once the work is complete (and you actually do rent it out) you can leave it classified as a rental. Of course, depreciation on existing assets will continue. Me personally, I would convert it to personal use to stop depreciation. But you don't have to. Not stopping the depreciation would only be a "potential" issue if you changed your mind and didn't rent it out once the work was complete.
As for the new appliances purchased during this time along with the cost of any other improvements/renovations, you wouldn't start deprecating them until all work is complete and the property is once again move-in ready.
Your maintenance cost are deductible so long as the property is classified as a rental.
The reason I would convert to personal use for such a long period of "down time" would be to stop the depreciation on the existing listed assets. Remember, depreciation is not a permanent deduction. You will have to recapture and pay taxes on it in the tax year you sell the property.
