2017 Nortek Checked system and found blown fuse in air handler. Checked all wiring and did not find any exposed wires or anything that could of caused a short blowing the fuse. Customer said there have been 3 power outages over the past few days, which could have caused fuse to blow. Replaced fuse and started system. Checked pressures and amp draw. System is working at this time. Customer signed up for membership.