Basic Electrical Circuit: Auto Flush on Pump

Just finished something I was working on and decided to look at a circuit you could have a use for. I will call it the Auto Flush on Pump and here is why:

You have a submersible pump and the sump does get some solids into it which, at times, blocks the intake on the pump. This results in the pump running, but not pumping. This has two bad results for you. First one is that it is not good for the pump to run dry and the second, you end up with the sump overflowing and creating a flood.

When you turn up to fix the problem, you simply turn the pump off for a few seconds and let the water that runs back in the pipe clear the blockage. Turn it back on and away it goes. With that in mind, let’s automate that function!

What the circuit needs to do is monitor the level once the pump has been started. If the level does not go down with the pump running, we simply make it stop for a pre-set time and then back on again. Now for this first circuit, I have not added any additional frills like alarms etc. Thought you will work that out and add them

Here is where we will start with the circuit. We have two float switches in the sump. One at low level where the pump will stop, and one at high level that will start the pump. Now we add the first timer to the circuit. This timer will start timing as soon as the start instruction is given by the high level float. The timer is set to a time that will be long enough for the high level float to change state. In other words, the contact will open. If this happens, it means the pump is working as the level is dropping.

Should the timer time out and the switch has not changed state, the pump will be turned off and the second timer starts timing. This timer is set for a short time to just allow water to run back and flush the pump. Once the second timer has timed out, the circuit will reset and the pump will start again. This is where you can start adding additional items to the circuit. Maybe you only want this operation to take place once only and if it is still not pumping trigger the alarm. Have a play with it and see what other suggestions you have.

Below is the circuit and this time I have not written the “walk through” of the circuit. Have a look at it and see if you can follow it all the way through. Feel free to comment on it. I have not wired this circuit with relay and timer combinations as shown. This is something that I would normally use a little programmable relay for.

Again, hope you find a use for something like this. Till next time, stay safe and think creative!

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  1. Pingback: Basic Circuit on Pump « sparkyhelp

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