Why are clients home to confirm outdoor TXV had failed. Client updated us on diagnostics that had been performed earlier today. We further discussed the design and ductwork of the indoor air handler. We proceeded to diagnose the outdoor unit and confirm that the outdoor TXV was not threaded, but it was in fact missing O-rings on the TXV component. I showed this to our client and we confirmed the brass fitting was not cross threaded. We discussed options for repairs and potentially wiring the indoor equipment to run only 1 thermostat. Will send options and let client decided how he wants to move forward.