I arrived at our clients home to the unit not cooling properly. He had recent power outages due to storms in the area. I proceeded to the outdoor unit fist and tested all the electrical components. Everything passed inspection. I then went inside and found the zone control board blinking with a low pressure error. I removed the discharge air temperature sensor and diagnose it to have failed. I showed my findings to our clients and we discussed how I would need to replace the sensor before I could further test the unit. I had a replacement sensor and tested the unit. I let the unit run for 20 minutes without any other lockouts or issues. I checked the refrigerant pressures and measured the temperatures at the indoor unit. The pressures were reading abnormal. Indicating low Freon pressures and I was only getting 13° drop at the indoor unit. We discussed how the unit may be low on Freon due to a leak. Our client had to get ready for work and he elected to monitor the unit for now. I w