Liberty Pumps Engineered Pump Systems (EPS) - Manual (Page 7)

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Pump not turning on
1) Check that control floats are unobstructed and operate properly
Most EPS systems come with control panels to operate the pumps. These panels commonly make use of float
switches to send a signal back to the panel. The floats will be positioned at various levels to accomplish the
intended pump cycle. As the water level raises, the floats will rise as well on their tether and activate a switch
located inside the float. If something inside the tank obstructs the float from rising, it would not be able to activate
and the control panel would not operate the pumps. This would usually result in the high level alarm triggering or
flooding. Likewise, if a float switch is trying to drop and it cannot because it is resting on another object, it would
not signal the control panel to disengage the pumps and they would run continuously. This would result in
overheating or damage to the system. Always check for proper float operation throughout the cycle. Take care
to notice if the float has the ability to hang up on anything inside the tank including the pumps themselves or the
power cords.
2) Check that panel has control power
Control panels utilize a complex series of circuits to properly control the duty cycles of the pumps. These circuits
must be powered, commonly with 120 V, single phase electric. The circuit powering the controls should be
separate from the circuit powering the pumps. There will be a dedicated set of terminals to connect power to the
control circuitry. Failing to power the controls will result in the pumps not operating automatically. Most panels
have an LED light that will turn on when control power is properly installed.
3) Attempt to run pump(s) manually with control panel
All control panels should come equipped with HAND-OFF-AUTO switches (H-O-A) that can be used to change
the operation of the control panel. The HAND mode is another name for manual. If the control panel is set to
HAND mode it will automatically run the pump no matter what the current liquid level is. The OFF mode does the
opposite. When the control panel is set to OFF mode it will not run the pumps no matter what the current liquid
level is. The AUTO mode is the normal operation mode. In AUTO mode the floats (or in some cases transducer)
will trigger the control panel to operate the pump, turning “On” when the liquid level reaches a certain height, and
turning “Off” when the liquid level falls to a certain height. If the pump(s) is not turning on in the AUTO mode, you
may troubleshoot the system by temporarily changing the control panel to HAND mode. If the pumps operate
and pump down the liquid level, this would signify that the problem is with sensing the water level, most likely one
of the floats is not working correctly. It could be out of position, obstructed, or defective.
4) Attempt to run pump(s) automatically by hand or by adding water to the tank
All of our systems are meant to run automatically. The pump(s) would be controlled by an automatic float switch
or through a control panel which would utilize either float switches or a pressure transducer. After installing a
pump system, it would be a good idea to run the pump(s) through a cycle by adding water into the pit in order to
operate the pump. If adding water is not an option, raising the float switches by hand in the order that they would
normally raise would simulate water entering the pit. If the pumps turn on, evacuate the water, and turn off, then
you would know that they system is working properly. This same method can be used to troubleshoot a pump
that is not turning on some time after installation. An advantage of using a control panel is that commonly each
float would have its own LED light inside the panel. By raising the floats by hand or with water, you could easily
tell if a float was not functioning by whether or not it turns on its corresponding LED light.