This study is on the compressor test rig for refrigerant change test. Increasing the production temperature is one of the main research topics of heat pump and for that compressor plays the key role. To ensure the reliability of compressor, both analytic and experimental approaches would be used. This study takes the experimental approach to check the reliability. Steam generation is the target operation condition. R245fa is selected as working fluid since it has good characteristics under the temperature range for steam generation. For effective experiments test rig based on bypass cycle is constructed. Long term experiment on refrigerant change is under operation. Change of lubricant will be scheduled later.