Can anyone tell me a procedure for draining the POE oil out of a carrier m/n 30hxc271nz-640ka chiller ? I have the refrigerant charge ( 134A ) isolated in the evap bundle. I have tried to pressurize the condenser bundle with nitrogen and drain the oil from a fitting on the oil pump suction line. I have only managed to remove about a gallon of oil. The spec says it holds 5 gallons. Any suggestions would be appreciated.