How to Prevent Short Cycling from Floats Out of Sequence
Are you having problems with short cycling or your panel alarm activating frequently? You could be experiencing a floats out of sequence issue.
In this article, we’re going to explain what happens when your floats are out of sequence. First, we’ll show you how a typical float sequence looks. Then we’ll explain what having floats out of sequence means and what causes it. Finally, we’ll walk you through some basic troubleshooting. Let’s get started!
Please use caution while handling your pump control panel. We have designed them with the highest safety standards in mind, however they are complex electronics and can cause death or serious injury if used improperly. Only follow the instructions provided here and contact our support team if you are unsure of what to do.
Typical Float Sequences
There are different float sequences depending on whether your panel is Demand Dose or Timed Dose.
In a demand dose simplex system, there are 3 control floats: stop, start and alarm. When the water level rises in the pumping chamber, it lifts the Stop and Start floats to the on position. Then the control panel calls the pump to run, lowering the water level. The pump continues to run until both floats lower back down to the off position.
If the pump is unable to keep up with the liquid demand and the level continues to rise, the alarm float will rise to the on position, activating the audible horn and visual beacon. The alarm will remain active until the alarm float lowers down to the off position.
In a demand dose duplex system, you can use either a 4 or 3 float system. The 4 float system has stop, lead, lag and alarm control floats. When the water rises in the pumping chamber, it lifts the Stop and Lead floats to the on position. Then the control panel calls pump 1 to run. The pump continues to run until both floats lower back down to the off position. The next time the pump is called to run, the control panel will call pump 2 to run. It alternates between the two pumps every other cycle, equalizing pump wear.
If one pump is unable to keep up with the liquid demand and the water level continues to rise, lifting the Lag float to the on position, the panel will then call both pumps to run simultaneously. Once all the floats lower down to the off position, the control panel will reset itself to a single pump alternating mode of operation.
The position of the alarm float in this system depends on the application. For septic pump stations or lift stations, it is recommended to have the alarm float level lower than the Lag float level, as this will provide alarm notification before your panel goes into Lag mode. In certain situations, it may be appropriate for the Lag float to be below the Alarm float. Please note that using this set up will not provide alarm notifications unless both pumps are unable to keep up with the liquid demand and the liquid level continues to rise. Neither of these situations will cause a floats out of sequence condition.
The 3 float system has stop, lead, and lag/alarm floats. Using the 3 float setup will have the Lag and Alarm functions activated simultaneously with the use of a single float.
In a timed dose system, both the simplex and duplex panels can use the same float sequence, with the difference being that the duplex system alternates between the 2 pumps every other cycle. The two floats in this sequence are the Timer Enable/Low Level Cutout float and the Alarm float. The dosing schedule always starts with the Off cycle. The Off cycle is the rest period in which the pump is not activated. It is the minimum amount of time between the On cycles. Once the Off cycle has stopped, the On cycle will start. The On cycle is the duration in which the pump is called to run. If the Timer Enable/Low Level Cutout float is still lifted up after a completed On cycle, the panel will call for another dosing sequence, starting with the Off cycle.
If the liquid level in the tank rises faster than the dosing schedule can accommodate, the alarm float will rise and activate the audible horn and visual beacon. The alarm will remain active until the alarm float lowers down to the off position, clearing the alarm condition.
With a timed dose system, there are two additional floats that can be added: Redundant Off and Timer Override. The optional Redundant Off float is designed to ensure the pump turns off when the tank does not have enough liquid to warrant a dosing sequence. This float is mounted below the Timer Enable/Low Level Cutout float. It is the lowest float in the tank.
Timer Override is the other optional float. It is designed to bypass the dosing schedule and call the pump to run regardless of current Off or On cycle state. This float is generally installed above the alarm float to provide alarm notification before timer override is activated. In certain situations, it may be appropriate for the timer override float to be mounted below the alarm float. Please note using this setup will not provide alarm notification unless the pump is unable to keep up with the liquid level demand.
What Happens in a Floats Out of Sequence Condition?
When your floats are out of sequence, it means that the float sequence order is incorrect, which can cause significant problems for your system. A common incorrect sequence is to have the lead float on the bottom, followed by the stop float. This means that your floats are doing the opposite of what they should. When the water rises, the pump runs for a few seconds, shuts off and then repeats the cycle again. This is called short cycling, and it has critical implications for your system. It shortens the life of your pump and puts extra wear and tear on the panel and floats. This can make it an expensive problem.
How can you tell if your floats are out of sequence? In our Installer Friendly Series® and older versions of the EZ Series panels, the panel will show an FE error and a combination of “o” and “c” from the float circuit that’s engaged. In newer EZ Series panels, the controller shows “float error”, with abbreviations for “opn” for open and “cls” for closed. In panels with our newest duplex controller, an indicator light will come on when the floats are out of sequence. However, in many instances there may be no indication other than short cycling.
How do floats become out of sequence? It could be that the float is no longer in the correct position in the tank. This can happen if the float cable detaches from the float bracket, cable weight or cable clamp. It also happens if the float was installed using an insecure method, such as a zip tie, which will corrode over time. The floats could also be wired incorrectly in the control panel. This can be as simple as mixing up the start and stop floats. In our next section, we’ll show you how to identify which problem you may be facing.
Troubleshooting Your Panel
How you troubleshoot your panel will depend upon what kind of problems you’re experiencing. We’ll walk you through a few common scenarios.
If your pump is short cycling on the second float, your Stop and Lead floats may be wired out of sequence or your Stop float may be stuck in the engaged state. Panels with a display such as our IFS or EZ Series will show a Float Error code. In addition, the alarm will activate if one of the other circuits is triggered out of sequence, which is typically bottom to top. If this is the case, you should check your floats.
If your alarm activates before the pump starts, the alarm float may be wired into the wrong float circuit. This will activate the alarm out of turn. If this is an existing panel that has 2 pumps, there may be an issue with one of the pump circuits.
If your pump is not activating on a Timed Dose Panel in auto, check if you’re using the Redundant Off float. On SJE Rhombus timed dose panels, if the Redundant Off float (or the optional lowest float in the tank) is not being used, it will need to be bypassed with a jumper wire. Panels with a display such as our IFS or EZ Series will show a Float Error code. In addition, the alarm will activate if one of the other circuits is closed while the OFF circuit is open.
If these scenarios don’t match the problem you’re having, please contact our tech support team for further assistance by calling 1-800-746-6287.