Customer is selling home and first floor zone not working, furnace a 33 error code for high limit code, checked all venting which was clear, pulled trap to make sure it wasn’t clogged, roll out switches not tripped, took temperature reading of heat exchanger and furnace would cut out at 125 degrees, tried this 4 times and each time right around 125-130 degrees furnace would shut down, high limit is set for 210-20, jumped out high limit switch and furnace stayed on supply temperature at 130 degrees, delta t at 70 degrees, ordered correct part furnace needs will need to call customer when it comes in, customer paid full balance.