A steam trap monitor includes a process variable sensor configured to sense a process variable related to operation of a steam trap. A memory contains information related to a baseline parameter of the process variable. Diagnostic circuitry calculates a current parameter of the process variable sensed by the process variable sensor and compares the current parameter of the process variable with the baseline parameter. Based on the comparison, the diagnostic circuitry responsively provides a diagnostic output based upon the comparison. The baseline and current parameter are based on a time period during which the steam trap is open or closed.

A valve control apparatus including: an operating time measurement unit that measures an operating time of a valve based on an operation pressure of the valve and whether the valve is open or closed; and a command control unit that receives an opening command directed to the valve and transmitted from a control apparatus, and transmits the opening command to the valve in a delayed manner based on the operating time and a predetermined reference time.