I need the design of a water control system involving moving water form a well to an overhead tank using a pump. There are two concerns I have: (1) I want to prevent "dry-running" of the pump by not allowing it to empty all the water in the well. (2) I want to prevent overflow of the tank when it is full so that water doesn't waste.
I have a ball-type float switch to control the level of the overhead tank. But I have an automatic water level controller (DF-96DK) that is designed with a 3-prongs sensor probe which I will use for the well to prevent "dry running". Because the pump is heavy and will surge, I have a CAD32M7C contactor which I intend to use for the power switching. I also bought a CNC SUL181d timer switch. This is to allow the water to still pump for a preset time to the overhead tank after the float switch has switched off. I believe this is necessary because when the float switch turns off, the tank is still not full and still requires substantial amount of water to fill it. I bought a green panel mount indicator lamp to indicate when the pump is on. I have a 2-position, self locking knob switch to mounted on the panel for "off" (manually override to switch pump off) and "Auto" (put control back into automatic working mechanism). I also have a 2-position key knob for panel mounting. It will have a "On" (manually override to switch the pump on no matter the poistions of the sensors), and "Auto" (put control back into automatic working mechanism).

Basically the mechanism is: 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 well and only switches off when lowest level of the well 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 (programmable by the timer) to enable water reach the top of the tank.

Kindly assist in designing the circuit for this pictorially. See the materials attached.

 

Is this a homwwork or course projevt or are you actualy building this project ? Do you want to use relay logic or logic ICs with a semiconductor device to switch the power to the contactor coil ?
Les.

 

Is this a homwwork or course projevt or are you actualy building this project ? Do you want to use relay logic or logic ICs with a semiconductor device to switch the power to the contactor coil ?
Les.

I want to actually build this project. I want to build it in a metal panel. No ICs. Just components like contactor, timer, float switch, indicator lamps, etc.

 

Hi Cuteajax,

you can start design your control circuit from this sample :

https://www.sumpalarm.com/blogs/sum...ystem-well-high-level-on-cistern-low-level-on

 

"sump pump float switch" There are many kinds. I use this on my well pump. When the well is dry the float switch falls down and turns off the electrical. Then there is water the float switch is up and connects the electrical. The length of the wire sets the on/off points.

Some low pressure pumps come with a float switch.

From the manual.

I have one switch like these that turn off then the well is too low. Then there is a second kind that turns on the power when the water is low that is used in storage tanks.

 

This is the third thread from the TS on basically the same concept.

 

I think that the timer is a bad idea. You Either need need a second level sensor in the overhead tank or you need to move the existing ball valve switch to the maximum fill level point. Adding a second level sensor would mean that the pump started when the water was at the lowest required level in the overhead tank. It would continue untiol ite reached the maximum required level then stop. If you just moved the existing sensor to higher level the pump would run every time some water was lost from the overhead tank.
I don't understand your reasoning for adding a contactor with a contact rating of 10 amps when the contacts in the DF-96DK are rated at 20 amps.
I have not been able to find a full datasheet on the DF-96DK but I did find this website with some useful informationn on the DF-96DK
This information suggests that the DF-96DK can do what you require without any other parts.
Les.

 

Kindly assist in designing the circuit for this pictorially. See the materials attached.

I got a chuckle out of the PB shown, appears to be a knock-off of the Group Schneider line??!
Sweideer !!??
I used them back when they were made be by Telemecanique Co.

 

check over here. Maybe you guys can strike up a deal.

water pump controller

 

The sump pump float switch shown in the post is in my evaluation the very worst choice for control of anything!
For the control of the water level in the tank, two conditions need to be sensed, which are almost full, to switch off the pump, and almost empty, to switch on the pump. For the well, only one condition needs to be sensed, which is LOW LEVEL, to prevent the pump from running or starting.
Adding a timer to keep the pump running after the tank upper level switch triggers is a poor choice at best.
AND, if possible, exchange the sensors so that the single float switch is located in the well, since only the lower level needs to be detected. Then the dual setpoint sensor can control the tank filling side of the system.

The bad news is that this post is too very similar to at least two other posts that are quite recent. So I suggest not simply re-posting the same question with different wording. That is a great scheme for assuring no answers at all.

 

I tend to go with these types of float switches where possible, https://www.pic-gmbh.com/fileadmin/user_upload/datasheets_en/pls041b3ppi_ds_e_5.4.pdf

 

Certainly those are very nice food grade switches, Max. Most of the float switches that I specified were for use in hot oil, often hot hydraulic system oil. A few were for either gasoline or Stoddard solvent. Not nice stuff at all.
For the well and tank question, electric pumps have been used with water wells for over 100 years now, both in the US and in many other parts of the world. So there should be a very large volume of literature someplace as to how others have made it work.