I purchased a new Trane XLi14 seer heat pump system with variable speed handler in OCT 2004 to replace my 16 year old system "old faithful". This summer ,when set to cool mode the system, I noticed a freezing/frosting on the line going into the handler. After 4 weeks, about 10 visits from a senior tech, a replaced TXV valve and coil the system still frosts at a thermostat setting of "75 degrees". I this normal for a high efficiency unit that the company promises a comfort level never expierenced? I have a tech coming out this afternoon to look at the problem again. (thank goodness for the 10 year warranty) any insights from anyone would be apprteciated thanks.