came out to a no cool on a 1999 R410a system. After a full diagnostic check. I found that the indoor unit was extremely dirty and needs to be cleaned. The filter was restricted and needs to be changed. I found that the unit did not have any Indoor Air Quality products on it. I found that the outdoor unit was also really dirty as well. I found that the capacitor and compressor were testing out of range. The refrigerant levels and pressures were good. The inside of the home is cooling but the thermostat is not registering the proper temperatures. We will need to change out the thermostat, clean the entire system and add a hard start for the compressor and a capacitor that will fail any day now.