How do I fix my High-Level Alarm on my Pump Station?

What is a high-level alarm?

Many pump stations include a high-level alarm as a standard function A high-level alarm panel incorporates a red light and audible alarm that activates when the liquid level in the pump station chamber reaches a particular height.

How does a high-level alarm work?

When set up correctly, a high-level alarm will be connected to a level sensor inside the pump chamber.  This could be a level float, or another kind of sensor such as a hydrostatic or ultrasonic level sensor (more commonly used in commercial applications).  When using floats, the high-level alarm float should be set as the highest float in the chamber. 

As the liquid level rises, the level sensor floats, a ball bearing inside the float will drop into place connecting an electrical circuit that causes the alarm to sound.

My pump station high level alarm is going off.  What should I do?

The first thing to do is determine whether the alarm is legitimate or if the system is malfunctioning.  The easiest way to understand this is to open the pump chamber and visually inspect the liquid level. 

If the liquid level is above the high-level float – the alarm is functioning properly and notifying you of an actual pump system fault.  To read more about these system faults, click here.

If the liquid level is not above the high-level float in the pump chamber (i.e. the float is hanging in the chamber) – it’s possible that the high-level alarm is sending a false signal. 

Some common causes are listed below:

1/ The high-level float is tangled on the pump lifting chains etc. Sometimes the liquid level is low, but the alarm level float is physically stuck in the upward position – keeping the high-level alarm sounding.  By untangling the float, the alarm will cease.

2/ The ball bearing is stuck inside the float. On occasion the ball bearing inside the float gets jammed in a position where it completes an electrical circuit sounding the alarm, even though the high-level float itself is no longer floating.  This can be fixed by giving the float itself a good shake to unlodge the ball bearing.

3/ The level sensors are wired incorrectly. If this is a new installation and you are finding that the high-level alarm is sounding before the pumps are engaging, its possible that the floats have been wired to the wrong terminals in the controller.

Double check this by individually lifting each float and seeing what activates in your pump station (as many pumps have automatic dry running protection, make sure there is sufficient water in the pump station for your pumps to run prior to doing this test).

If the highest float engages the pumps, and the lowest float sounds the alarm – the wiring in the controller is backward to how the floats are positioned. 

The two options here are to A) switch the position of the floats in the chamber so that the high-level float is highest in the chamber (usually about halfway up), or B) swap the float terminal connections in the controller.

4/ The float switch is faulty- Sometimes water ingress or a break in the internal wiring of the float cable can cause a false signal to be sent to the controller.  If the above causes have been ruled out, replacing the float switch may be the best solution.  Try disconnecting the float from the controller – if the alarm ceases and the above points don’t apply – then fit a new float switch to the controller and see if the problem is fixed.

If these common causes don’t solve your high-level alarm – you may need to seek expert advice.  

For more information, get in touch with a Pump Stations team member for assistance.