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How does a reed float switch work?
To complete a circuit, float switches utilize a magnetic reed switch, which consists of two contacts sealed in a glass tube. When a magnet comes close to the two contacts, they become attracted to each other and touch, allowing current to pass through.
Do float switches go bad?
As with any piece of equipment, a float switch will have a limited operating life. However, if the switch is used properly and maintained, there is no reason that it should not last for many years. Even the wrong type of switch may work in the short term, but it is going to be much more likely to fail or malfunction.
Do magnetic reed switches fail?
Reed switches or relays eventually fail in one of three ways . They do not open when they should (usually called “sticking”), they fail to close when they should (“missing”), or their static contact resistance gradually drifts up to an unacceptable level .
How do you fix a float switch?
- Replacing a Float Switch.
- Prepare the Sump Pump. Allow the sump pump to run until all water has been removed from the sump basin.
- Remove the Float Switch.
- Open the Switch.
- Replace the Sump Pump and Test.
- Prepare the Sump Pump.
- Bypass and Seal the Original Switch.
- Test the Pump.
How does a pump control circuit work automatically?
The bottom switch will be closed provided the liquid is above that switch point. The liquid rises until the top float switch closes and energises the relay. One set of relay contacts connects the pump to the supply and the other maintains the relay on-state, while the level falls towards the bottom switch.
What kind of Relay does a water pump use?
This system utilizes two levels of float switches, a 12V relay and a 120V relay to drive the pump. 12V DC is supplied to the float switches, which are normally open when not being floated. As the water level rises it lifts the bottom float (Float 1) and closes it.
How does the feedback loop work on a water pump?
However, a feedback loop is added between the NO pin and the + side of the relay coil. As the water level falls and the top float switch opens, current continues to flow through the bottom float switch, through the COM and NO pins and back to the relay coil, keeping the relay energized and the pump on.
What kind of diode should be used for pump control?
A 1A Silicon Diode (IN4006) should be connected across the coil terminals, if the control voltage is DC (see diagram below). These measures are to avoid back EMF, induced over voltage transients, which can cause damage to the reedswitch contacts.