I bought a new house and had the builder (subcontractor) swap out the standard unit for a XP16. When he put it in he said that they swapped the threading type in the air handler and he needed a different TXV, which he didn't have. He left the old metering system in (looked like just an inline piece with a small hole in it). Am I at risk of damaging the unit by running it withouth the TXV? Same installer also knew nothing about controlling the 2nd stage of the compressor. I'll open up a new thread about that.