economizer shutoff valves 54 are placed on each of the economizer return lines 52 as is known the economizer flow is returned from manifold 38 through return line 52 and the valves 54 into economizer compressor ports 55 as is known this refrigerant is returned at an intermediate point in the compression cycle of the compressors 22 and 24 if the valves 54 are closed and the unloader valves 50 are open then refrigerant can move from the economizer ports 55 outwardly of the compression chambers through the lines 48 and into the lines 46 this allows either one or both of the compressors 22 and 24 to operate in an unloaded mode also as is known a pressure equalization line 56 can connect the low pressure side of the compressors 22 and 24 for proper oil management further an oil equalization line 58 may separately connect the compressors to additionally improve oil management for the tandem compressors when operating the refrigerant cycle 20 the compressors can be operated in economized mode non economized mode unloaded mode and economized unloaded mode either or both of the compressors can be operated in any of those modes and thus several levels of capacity control are provided fig2 shows an alternative embodiment wherein a first economizer shutoff valve 60 is placed on the common manifold 38 a second economizer shutoff valve 62 remains on the return individual economizer line 64 for the compressor 22 and controls refrigerant flow from the manifold 38 to the economizer port 63 the other economizer return line 56 leading to the compressor 24 and the economizer injection port 67 does not have an individual shutoff valve when control 100 controls the economized operation between the compressors 22.