North Star MD40 Logging Oil
Good Evening All,
Been working on a Northstar MD40 flaker with a Bohn condensing unit (404) running two Copeland compressors. When I arrived the unit was off on oil pressure switches. No oil in comps or reservoir. Filled comps with oil. The unit ran but comps pumped oil out to system and no oil returned. Checked oil filter - ok, checked oil separator - ok. Finally checked for oil at the evaporator and I was able to pull out a five gallon bucket of oil before I had to leave (im sure there is more). The oil returns off the bottom of the unit and is supposed to run through a heat exchanger, which uses heat from liquid line to boil refrigerant from oil. The installing contractor did not install a heat exchanger.. Instead, the oil line comes out of the bottom of the evaporator rises to an elevation about three feet above the top of the ice maker and then stabs into the side of the suction line. I guess they were thinking that the refrigerant/liquid would enter suction line and be separated at the accumulator. That is all fine and well but I don't understand how the oil would ever be able to flow from the bottom of the exchanger (suction pressure) to the suction line which is at the same pressure. There is a sight glass in the oil return line and I do see oil in the glass but no movement. I checked for restrictions and didn't find any from the evaporator to the suction line. Anybody ever seen an ice flaker installed this way? Any help would be appreciated.