thank your contracter for selling you a outdated system. I hope they gave you a price cut since Trane was almost giving those away recently.
*** Compared to normal price ***
Now that's the last thing the customer wants to hear. Just because the XL20i is now available doesn't render the XL19i outdated as a product, just as the XR13 units come in both R-22 and R-410A still. Still active in the AHRI directory. We also don't know when exactly the system was installed: "just" may mean a month ago to the OP.
I have replaced check valves in Trane coils to a spring loaded valve to prevent a banging or load knocking sound coming from the air handler in the heat mode before. Also just a couple days ago we had another complaint and I found out that the new coils now use a non-bleed TXV valve with internal check valve. They sent use a new pressure bleed valve type with internal check valve. You have to soldier in a access valve that the TXV valve equalizer tube screws to, customers happy so far.