Mainfloor Lennox air handler/ heat pump was freezing up. I Found the breaker for the air handler (on the air handler is loose and staring to fail). The system is short on air flow. Needs another 10” return run and an additional supply run. I also found that the outdoor unit is a 3.5 ton indoor unit and the outdoor unit is only a 3 ton system. I used the Lennox app and verified the equipment sizes. I recommend that the indoor unit and the outdoor unit get replaced. Additional ductwork should be added on the return and supply side of the system. System will never run right and will continue to freeze up and be a potential water hazard until replaced. Homeowner said he would contact the builder.