I have a problum with a walk-in cooler with a McQuay RLC-200C-M_11 evaporator and a Tecumseh AgA4534Axa condensing unit and a sporlan Cfe-3-c valve runing 10 degree superheat and 18 degree saturation temp. Coil freezes up in an hour. I think it is because the txv is too large. I need some feed back. O,THE frost is even.