No, you have to treat it as a casualty loss with insurance. Form 4684 is confusing, but read each line carefully. Very carefully. If the heater and air conditioner were being treated as part of the building, you don't have any gain or loss. Although a LOSS is the lower of basis or unreimbursed drop in Fair Market Value, FMV is ignored for a GAIN. It is only taxable when excess reimbursement exceeds the basis of the property. So just reduce basis by $3000. You really don't even have to put any of it on the tax return.
On the other hand, heater and a/c are odd things to steal. Were they vandalized? If they were appliances instead of real estate, with no extra cost basis at purchase, the $3000 will end up on the last line and then go to Form 4797. No, I take that back. You have $10000 gain, and new depreciation on $7000.