SubMonitor Pump Protection: Much More than an Overload Sensor

As all water systems professionals know, a submersible installation can be a tough environment for both pump and motor. Sometimes, no matter how professional the installation, things out of an installer’s control can severely damage a customer’s investment. The answer to such problems is the SubMonitor pump protection system, which offers state-of-the-art protection for Franklin 3- phase installations all the way from 5 through 200 Hp. The SubMonitor system keeps track of voltage and current, as well as motor temperature in motors equipped with Subtrol heat sensors. Introduced in 2004, SubMonitor protection will shut down a motor in the event of a variety of fault conditions including high voltage, low voltage, overload, underload, false start, current unbalance, overheating, phase loss and phase reversal. The unit is easy to set and read. And, one model covers all ratings – without rating inserts.

SubMonitor Setup

For all of the protection described above, SubMonitor set-up is easy and accomplished with a simple display and turn-and-push knob. When installing the unit, simply select the motor frequency (50 or 60 Hz), voltage and service factor amps (from the motor nameplate or AIM Manual). At that point, the unit is ready to run using factory-default settings. To accommodate individual installations, the user can easily adjust the factory defaults. See the chart on the reverse for a list of programmable options.

SubMonitor Operation

Once the SubMonitor system is operational, the readout on the display head shows voltage and current on each leg, as well as pumping status. The fault light can be seen from a distance, indicating that a trip has occurred and that a fault message is being displayed. The SubMonitor memory can recall a history of the past 500-plus events. When set to “Detailed Logging” mode, “events” may include normal starts and stops, fault trips and any changes made in parameters. The event history can be reviewed at any time via the Data Logging option on the SubMonitor menu. A handheld unit will soon be available that will allow the contractor to download the event history to a computer.


SubMonitor protection is available in three options: Standard, Premium and Panel-Mounted. SubMonitor Standard includes the SubMonitor base unit and display head only, while SubMonitor Premium adds a surge arrestor and is eligible for an extended warranty when installed with a new motor. The Panel-Mounted SubMonitor system is installed in a Franklin 3-phase control panel and also provides the extended warranty. For more information about how SubMonitor can protect your 3-phase installation, call the Submersible Service Hotline at 800-348-2420 or visit Franklin’s website,

 Programmable Options