Is the TXV valve installed on this unit at the factory? Or to be installed at time of installation?

ARUF37D14 does not come with a TXV by default. It uses a flowrater instead. The TXV would be installed with the air handler on site. The correct TXV kit for this air handler is the TX3N4, which as of 8/28/23 we will have in stock in about 1-2 weeks. If you cannot wait that long, our salespeople can help you explore your options for alternatives. Please give us a call if that is the case.