A method of monitoring a volume index valve of a screw compressor comprising: recording a first reading of an operating condition of the screw compressor when the volume index valve is in a first state that corresponds to a first position; switching the volume index valve to a second state that corresponds to a second position; recording a second reading of the operating condition of the screw compressor when the volume index valve is in the second state; calculating a difference between the first reading and the second reading; and comparing the difference to a predetermined threshold difference to determine if the volume index valve is moving between the first position and the second position in a desired manner; the method further comprising: verifying that the volume index valve is opening and closing in the desired manner if the difference exceeds the predetermined threshold; determining that the volume index valve has failed and is not opening and closing in the desired manner such that it is impairing operating efficiency if the difference does not exceed the predetermined threshold; wherein the method is automatically initiated based on a periodic timer to cause the method to be performed at a specified time interval, wherein upon initiation of the method, the method comprises waiting for stable operation conditions of the screw compressor to be met and/or stable operation conditions of the system that the screw compressor operates within. recording a first reading of an operating condition of the screw compressor when the volume index valve is in a first state that corresponds to a first position; switching the volume index valve to a second state that corresponds to a second position; recording a second reading of the operating condition of the screw compressor when the volume index valve is in the second state; calculating a difference between the first reading and the second reading; and comparing the difference to a predetermined threshold difference to determine if the volume index valve is moving between the first position and the second position in a desired manner; the method further comprising: verifying that the volume index valve is opening and closing in the desired manner if the difference exceeds the predetermined threshold; determining that the volume index valve has failed and is not opening and closing in the desired manner such that it is impairing operating efficiency if the difference does not exceed the predetermined threshold; wherein the method is automatically initiated based on a periodic timer to cause the method to be performed at a specified time interval, wherein upon initiation of the method, the method comprises waiting for stable operation conditions of the screw compressor to be met and/or stable operation conditions of the system that the screw compressor operates within. verifying that the volume index valve is opening and closing in the desired manner if the difference exceeds the predetermined threshold; determining that the volume index valve has failed and is not opening and closing in the desired manner such that it is impairing operating efficiency if the difference does not exceed the predetermined threshold; wherein the method is automatically initiated based on a periodic timer to cause the method to be performed at a specified time interval, wherein upon initiation of the method, the method comprises waiting for stable operation conditions of the screw compressor to be met and/or stable operation conditions of the system that the screw compressor operates within. <EOS>