I resently put together a dual fuel system with these as my system components : TWZ9048 XL19i Heat pump, 2TXC049 Indoor coil, TUH100V4 XV95 furnace. Trane technical support states that the unit will be overcharged in heat mode if properly charged in cooling mode. Appearently it comes down to a coil volume issue. The XL19i has way too much volume as compared with the 2TXC049 so that in heating mode you would have too much liquid refrigerant for the condenser to properly handle. Appearently the properly matched coil for a 4 ton XL19i is a TXC060 (five ton indoor coil) My questions are : What problems (if any) have you guys seen out there from a system set up this way? Also What would one do when installing a 5 ton XL19i (or XL20i as is now the case), and what do you think about just running my system on 1st stage (1/2 capacity) only? My thinking is that at 2 tons capacity maybe the indoor coil volume discrepency wouldn't be a significant factor given a reduction in refrigerant flow. Id rather not adjust my system charge seasonally if I don't have to. Any input is appreciated.