These devices buffer any pressure wave fronts
These devices buffer any pressure wave fronts coming to the sensor but will not alter your system. Just unscrew the transducer, screw one of these in, and screw the transducer back in. Make sure you get one rated for 4000psi. I've used Mid-West Instrument's model 200 "Gauge Minder" because it has spring loaded/adjustment for the shutoff pressure, rather than a floating ball the requires some amount of flow to move the ball to the shut-off position.
It's saved many a transmitter or mechanical gauge from overpressure spikes.
Another possibility along the lines of what itsmoked suggested:
It's possible that someone ran the transducer wires parallel to a 480V cable or wires feeding the pump and as soon as the pump turns on, it is inducing a voltage onto the sensor leads. But if you measure the voltage when the pump is not running, you will not see anything abnormal.
Are you using a diode to prevent any type of back feed into this circuit?(If not try anyway).Cheap low maintenace easy to fit and if its not a problem at least you have eliminated it from any assumptions later????
2011-07-24
