Arrived for AC MAINTENANCE. Ran static pressure test and found it to be operating above designer max static. We opened up vents in the home and installed a clean filter. Static pressure dropped some but is still failing. With the inspection camera we found a crack in the heat exchanger. Showed home owner the crack and signed a red tag. Called out supervisor to finish diagnosis on static pressure. Ran amp draw on outdoor unit and everything passed. Good charge on refrigerant. Performed coil cleaning. AC is operating well at this time, furnace is disabled due to unsafe operating conditions.