I need the design of a water level control system involving two tanks (an upper tank and a lower tank).
I have a float switch to control the level of the upper tank. But I have a floatless switch (Omron 61F-GP) with a 3-prongs sensor probe for the lower tank. I have a water pump in-between the two tanks. The pump should be automatically turned on when the upper tank reaches the lower level (as indicated by the float switches). It pumps water from the lower tank and only switches off when lowest level of lower tank is reached is reached. The pump should also switch off if the upper level of the upper tank is reached, though with a little delay of some 30 seconds to enable water reach the top of the tank. kindly assist in designing the circuit for this pictorially. In short, how do I connect a float switch for supply tank and floatless relay switch for drainage tank in a water level control circuit involving two tanks? The components to include contactor, MCB (as isolator switch), auto/manual override switch, on/off indicator lamp(s), power source, etc.

 

What does the pump do exactly?
Pump water from the lower tank to the top tank?


When

 

You've indicated the upper tank's float switch reads both high and low, what about the lower tank?

 

It sounds like you would connect the two level switches in series.
That way both have to be ON for the motor to run, and the motor is OFF if either one is open.

But I don't understand this requirement(?):

if the upper level of the upper tank is reached, though with a little delay of some 30 seconds to enable water reach the top of the tank

 

What does the pump do exactly?
Pump water from the lower tank to the top tank?


When

yes. pumps water from lower tank to a top tank such that the lower tank doesn't experience "dry running" and the upper tank doesn't experience overflow.

 

You've indicated the upper tank's float switch reads both high and low, what about the lower tank?

A floatless switch is connected to the lower tank to prevent "dry-running".

 

It sounds like you would connect the two level switches in series.
That way both have to be ON for the motor to run, and the motor is OFF if either one is open.

But I don't understand this requirement(?):

that requirement is just to prevent the float switch from cycling on and off with the slushing of the water as it is feeling.

 

that requirement is just to prevent the float switch from cycling on and off with the slushing of the water as it is feeling.

So the two float switches in series would control a 30s off-delay timer to the motor.

 

The components to include contactor, MCB (as isolator switch), auto/manual override switch, on/off indicator lamp(s), power source, etc.

What is the supply voltage and current required for the pump and what voltage is the 61F-GP sensor using? Does the sensor have upper and lower probes in use for the lower tank?
Voltage and current rating on the float switch and/or any links to the pump and float switches.

 

The thirty second delay is a fallacy because the tank is already at the set level to trip the float switch.
This is a classic design problem, and with the required list of components it seems like a class level assignment.
There will be no level switches in series, but rather the classic two switch start/stop control for each pump. The bad news is that with that non-float switch " a floatless switch (Omron 61F-GP) with a 3-prongs sensor " we will need to do research to discover how that switch functions. But I do not do that research for this forum site.

 

There will be no level switches in series, but rather the classic two switch start/stop control for each pump.

You sure about that?
The TS needs the upper pump to stop when the lower tank becomes empty or the upper tank is full.
How would you do that without connecting the two level sensors together?

Although I do realize that just connecting them in series won't necessarily work.
May have to add a relay so that the upper pump stops if the lower pump is on (indicating the lower tank has reached empty and is filling).

 

What is the supply voltage and current required for the pump and what voltage is the 61F-GP sensor using? Does the sensor have upper and lower probes in use for the lower tank?
Voltage and current rating on the float switch and/or any links to the pump and float switches.

The supply voltage for the pump is 220v. It is a 1Hp pump, so perhaps maximum current is 10A to compensate for inductive surge. The 61F-GP sensor is also using 220v (primary voltage). It has upper and lower probe in use for the lower tank. The secondary voltage is 8VAC. Other details on the floatless switch can be found here
https://www.aliexpress.com/item/32673117955.html?spm=a2g0o.cart.0.0.736a38dasziVGA&mp=1

 

The thirty second delay is a fallacy because the tank is already at the set level to trip the float switch.
This is a classic design problem, and with the required list of components it seems like a class level assignment.
There will be no level switches in series, but rather the classic two switch start/stop control for each pump. The bad news is that with that non-float switch " a floatless switch (Omron 61F-GP) with a 3-prongs sensor " we will need to do research to discover how that switch functions. But I do not do that research for this forum site.

The details on the floatless switch can be found on this site:
https://www.aliexpress.com/item/32673117955.html?spm=a2g0o.cart.0.0.736a38dasziVGA&mp=1

 

You sure about that?
The TS needs the upper pump to stop when the lower tank becomes empty or the upper tank is full.
How would you do that without connecting the two level sensors together?

Although I do realize that just connecting them in series won't necessarily work.
May have to add a relay so that the upper pump stops if the lower pump is on (indicating the lower tank has reached empty and is filling).

There is only one pump. No upper pump or lower pump. There is upper tank and lower tank in any case.

 

OK,I did not get the details right on the installation. This is not the classic two pump system.
The floatless level sensor switch needs to feed one pilot relay to switch off the pump when the lower tank becomes empty. A second pilot relay is required to switch off the pump when the upper tank becomes full. So the normally closed (NC) contacts of those relays will need to be in series in the stop control for the pump starter contactor. The single start command will be from the pilot relay operatad by the EMPTY float switch of the upper tank. Starting the pump will be prevented by the operation of the lower tank "empty relay.

One serious caution is that there does not seem to be any thing that stops the lower tank overflow if the upper tank is already full.

 

There is only one pump. No upper pump or lower pump. There is upper tank and lower tank in any case.

Are there two float switches in the upper tank for high and low detection?
Are the switches open or closed when submerged?
What's the mechanism for refilling the lower tank?

 

I am guessing that the switches have "form C" contacts, that is SPDT configuration. AND, no mention of any control of the filling of the lower tank was mentioned. We were both considering the classic control problem, this one is a bit different. The two pumps and two tanks classic is way to well known. This version is different.

 

My understanding is that to this basic layout, we need to add in 'lower tank not low'. You might get by without a timer, if you shroud the floats/sensors, which would be just good practice. I recall a couple of instances where sensors were placed under a dome with a metering hole in the top, which acted as snubber.

You might get away with the float switch interrupting the motor contactor.

 

Post #18 is a wiring diagram, it is not a circuit schematic. I already described the system in post #15.It includes inhibiting the start of the pump when the lower tank is empty, as well as stopping it when the upper tank is full.

 

Post #18 is a wiring diagram, it is not a circuit schematic. I already described the system in post #15.It includes inhibiting the start of the pump when the lower tank is empty, as well as stopping it when the upper tank is full.

except that the floatless is latched, being empty until it's full, and full until it's empty. Will that work in this application? I have no idea.