I have a bryant 310AAV048135 furnace. What is the max size A/C unit I can install without having problems? The furnace and the A/C unit is about 7years old. My house is 2,800 square feet and have a 4 ton A/C unit, sales people are telling me that is the upper limit of a 4 ton A/C unit and recommend a 5 ton unit. I live in Michigan, can this furnace handle a 5 ton A/C unit?? Thank you