A packaged terminal air conditioner unit (PTAC) includes a sealed system having an outdoor heat exchanger and an indoor heat exchanger fluidly coupled through a line filter assembly. The line filter assembly includes a housing defining an indoor port having a first cross sectional area and being fluidly coupled to the indoor heat exchanger, a bypass port having a second cross sectional area smaller than the first cross sectional area, and an outdoor port fluidly coupled to the outdoor heat exchanger. A line filter is coupled to outdoor port for filtering the flow of refrigerant passing in one direction and a check valve within the housing prevents flow through the line filter in the opposite direction. A bypass conduit provides fluid communication between the bypass port and the outdoor conduit to bypass the line filter.