Stop, Look and Listen Vacuum Gauge. One of the most important pieces of equipment a milker should observe is the vacuum gauge. Vacuum gauges should be located in the vacuum line above the trap or even the balance tank, where milkers can see it from any position in the milk barn. Vacuum level, as indicated on the gauge, should remain steady. If vacuum level fluctuates more than an inch at any time during the milking operation, there may be a problem.
Vacuum fluctuation can have many sources.
Along with watching the vacuum gauge, a milker should be aware of the hissing sound the controller makes during normal operation . Sluggish response to vacuum changes may be caused by a faulty or dirty controller. Air entering the controller decreases when machines are attached or detached. The hissing will increase in pitch when air flow in the system is being restricted. If the hissing sound from the controller changes and remains at a higher or lower pitch, the controller may be dirty or sticky.