Septic Tank Float Switches

Overview

Float switches are an integral part of your septic system they tell your septic pump to turn on and off, they also let you know when there is a problem and the water level is too high. There are a couple of different float switches, and they serve various functions.We will go over that briefly below.

Control duty floats control alarms, and pumps in some cases and are not directly tied to the pump. They are wired directly to the control panel, and then the control panel has a relay that activates anything that needs to be done. The control duty floats or sensor floats have a maximum amp rage rating of five amps and are mercury activated. The basics of the operation are the float come up closing contacts and that in turn hit the relay switch which enables and takes the load of whatever was turned on.

Pump duty or pump floats are wired directly to the pump wires and are designed to take on the amp load of a pump motor running. The electrical charge that powers the pump runs through the float switch. Pump floats have an amp rating of 13-15 amps and have a lock amp rotor rating of 50-96 amps. Pump duty floats should always be changed when a new pump is installed if not you run the risk of ruining your new pump. The old pump on the system would have pulled more amps due to age as they get older they start drawing more amps and eventually that's why they fail. Because of this, they damage the float, so that is why it is necessary to change the float switch at the same time.

Float switches are an addition to an electrical circuit that allows for autonomous detection of fluid levels. Their primary use is to close a circuit when the fluid level reaches a particular height or depth. A closed circuit means that electricity is able to flow through the circuit’s components and power them. On the other hand, an open circuit is one that will not allow current to pass through the components. As fluid levels rise, a float switch will be lifted up with the water level. This means that the float switch will go from facing downwards to facing upwards. The upward orientation will typically cause a float switch to close, but the direction in which a float switch closes depends on the specific float switch.

There are a few terms that will tell you if a float switch will close a circuit if it is in the up or down position. The normal position of a float switch is hanging down. A float switch will hang down from where it is mounted when the fluid level is low. Septic systems typically want to close a circuit and turn on a pump when the fluid level gets to a certain height. This means that float switches in septic systems will spend a lot of time in the down position waiting to detect a high-water level.

A normally open float switch will open a circuit when it is in the normal position. This means the circuit is effectively turned off when the fluid level is low. A normally open system will have a closed circuit when the water level is high. This orientation makes the normally open float switch a good fit for most septic systems. A typical septic system will want to pump out effluent when too much of it builds up in the tank. The rising effluent level will lift up the float switch and cause the circuit to close. The closed circuit will turn on the effluent pump and return the effluent to the desired height.

A normally closed float switch will operate in reverse of a normally open float switch. Normally closed means current will flow with a low fluid level, and current will not flow when the fluid level is high. This system may be used when the user needs the fluid level in a system to be above a minimum height

There are two general types of mechanisms that a float switch may use to close the electrical circuit. The first type of mechanism is mercury. The mercury within the float switch will move as the fluid level changes, and that movement with open or close the system.

The second type of mechanism is more mechanical in nature. A mechanical float switch will contain a ball bearing. As the fluid level changes, the ball will roll within the float switch. The ball will then push on the internal components of the float switch and cause the circuit to open or close.

Float switches can also come in the wide angle or narrow angle varieties. A wide-angle float switch has to move a relatively far distance to engage the system. These types of float switches can be used if a fair amount of change in fluid level is acceptable or to be expected. Narrow angle float switches will move a relatively shorter distance before they engage the system. These types of float switches should be considered if the user wants to maintain a more constant fluid level.

In the case of septic systems, the float switch is used to detect the level of effluent in a septic tank. The effluent pump will begin to pump when the float switch is closed. This will cause the effluent level to drop and will eventually open the circuit when the level gets low enough. This system will allow your septic system to regulate the level of effluent in the tank without requiring the user to look inside of the tank to determine if the pump should be engaged.

It is a good idea to change out the float switch in your septic system when you change your effluent pump. If an effluent pump stops working, the level of effluent in your tank will rise above acceptable levels. Your float switch will notice the high-water level and will try to turn on the pump. However, a broken pump will not empty your tank. This can lead to a situation where your float switch is kept on for an extended period of time. A constant current may cause the float switch to become stuck in the on position. This situation could cause your new effluent pump to be run continuously. This is because the float switch has been damaged and is still telling the pump to empty an already empty tank. This situation can cause your pump to burn up or simply shorten the overall life of your new pump. Replacing the float switch when you get a new effluent pump will keep your system running smoothly for a longer amount of time.

Keep in mind that many systems require more than one float switch. Systems that use a timer may have an override float switch. This override switch is to activate the pump when the fluid level becomes too high. Some systems may use an array of float switches to regulate the fluid level, override, and an alarm. It is important to know the number and types of float switches that your septic system requires.

• Float switches are used to turn things on and off based on fluid level
• Know if you need a normally open or normally closed float switch
• Know if you need a wide-angle float switch or narrow-angle float switch
• Change out the float switch when you change your effluent pump