A combined accumulator and receiver tank of a refrigeration system is described. The tank may have an accumulator portion positioned above a receiver portion. An accumulator/receiver pipe (AR pipe) connects the accumulator portion to the receiver portion. The AR pipe may have a valve that allows liquid refrigerant to flow from the accumulator portion to the receiver portion during a heating and/or defrost, and prevent the fluid flow when the refrigeration system is in a cooling cycle. In some embodiments, a side opening that is connected to the AR pipe is above an oil pick up orifice of an accumulator suction line pipe.