Replacement warranty. Upon arrival, system is operating in heating mode. Shut system down to inspect door switch. Door switch is good. Checked code history and found codes for limit trip. Test ran unit and checked gas pressures. Both high and low stage pressures were about the range. Set low to 1.3inwc and high to 3.2inwc. Test ran both stages. Both stages operating within range at 45F temperature rise. No other issues found or suspected.