What Can Gauges
Tell You About Your Centrifugal Pump?
A gauge is one of the best ways to troubleshoot when your centrifugal
pump isn't quite working as it should, or simply isn't operating
at optimal efficiency. Here are 6 things a gauge can tell you
about the state of your centrifugal pump, so you can stay on
top of problems before they occur and save on expensive downtime.
1) The Total Dynamic Head (TDH)
The Total Dynamic Head (TDH) is the total height that the fluid
is to be pumped, taking friction into account. If water is the
fluid, TDH is the difference between the inlet and outlet of
the pump when measured at the same elevation. You will notice
that there is a high reading on the discharge gauge if TDH is
too high, and a low reading if TDH is too low.
2) Why Your Pump Isn't Running
If the pump is not running, you can perform a static reading
to discover if there is a suction leak. A suction leak is when
one of your pipes is sucking in air rather than water. Check
the length of the pipe to make sure that all fittings are airtight.
There could also be a discharge check valve problem. This might
occur when the valve is shut and the pressure generated is not
enough to overcome the shut valve.
3) If your pump has a plugged suction line
If you have a plugged or clogged suction line, the vacuum gauge
reads very high. Clear the suction line of debris, otherwise
you'll have low flow out of the pump.
4) The pressure of your self-priming pump
For self-priming pumps, the gauge can provide unique information
such as whether there is enough pressure before the pump comes
to prime. Should your pump not be able to dispel air from inside
the pump, create a low-pressure area at the impeller eye, or
be improperly sized, failure to prime is an inevitable result.
5) The pump's ability to pull a vacuum
Gauges allow for a maximum vacuum test, which provides information
on the centrifugal or self-priming pump's ability to pull a
vacuum. Low vacuum is an indicator of trouble on other parts
of the machine, which must be attended to immediately.
6) Whether vortexing or entrained air is occurring
Gauges allow you to determine if vortexing is occurring, which
is an issue that all centrifugal pumps experience. This problem
refers to when water is drawn into a suction line and a depression
then forms in the water. The vortex can lead to the pump entraining
air because the pump will want to pump air, since this is easier
to pump than water. This can cause the pump to operate less
efficiently. With vortexing or entrained air, gauge readings
will be lower than normal and vibrating.
Gauges will only provide accurate readings if they are properly
installed, so make sure your pump is fitted with the right gauge
and that gauge taps are as close to the pump inlet and outlet
By using gauges to provide enough information, you will be
able to make sure that your pump is highly efficient, while
prolonging its lifespan. If you have any questions about gauges
and implementation, please call our toll-free number 1-800-
367-4180. We have experts on hand to help you choose, install,
and maintain a variety of equipment.