Installing automatic switch to well pump

[thaisail]

I want to instal an automatic level control switch to a new 1000 liter water tank so that I can fill the tank using a 1.5 HP submersible well pump in a 40 meter deep well. The pump control box is in my garage which is about 10 meters from the float switch on the 1000 liter storage tank. The on/off switch for the pump is a two pole switch on the side of the control box that will open and close the line and the neutral at the same time when turning off and on the manual switch.

 

I bought a magnetic contactor with a 220 volt coil so that I don't have to have 7 amps of current running through the wires to the tank and back. I also see that the control box is opening the circuit to the line and the neutral when turned off which will prevent the wire to the run capacitor from being energized. Since my tank level control switch will be operating the magnetic contactor and the contactor is for 3 phase, I was thinking of connecting the line and the neutral going into the pump switch through two of the three sets of contacts on the contactor and when the coil is energized, the line and the neutral will bypass the switch and connect to the opposite side of the switch and start the pump by having the contactor run in parallel with the manual switch. When the contactor coil is energized the pump will start and stop with the contactor but if I want to manually turn on the pump, I can just turn on the manual switch and the pump will start if I want to fill up our pond. In this case I would shut the valve for the supply pipe to the 1000 liter tank and open the valve to fill up the pond. Don't know if this will make sense to anyone but photos of all the componants are attached.

[OneMoreFarang]

I am not sure if I understand everything you write. But my initial idea is: Why don't you use i.e. 12V on that switch and switch with that a 220V relay. The voltage and current through that switch is minimal and not critical as long as it's good enough to activate the relay.

 

Something like this:

https://th.aliexpress.com/item/33055432389.html

 

[Thorgal]

I use a timer switch on my pump to fill the tank of 1500L during peak moments of the day. I don’t use a level switch. Maximum water consumption/day for my family is 1200L. I always have minimal 300L reserve in case of extreme consumption.

 

You can add a pressure switch (Danfoss type 3 phase) on your well pump to operate any bypass lines like your extra water supply to your pond by opening the valve.

[thaisail]

3 hours ago, OneMoreFarang said:

I am not sure if I understand everything you write. But my initial idea is: Why don't you use i.e. 12V on that switch and switch with that a 220V relay. The voltage and current through that switch is minimal and not critical as long as it's good enough to activate the relay.

 

Something like this:

https://th.aliexpress.com/item/33055432389.html

 

Thanks for your idea. But I already bought the contactor with the 220 volt coil. I think there is very little risk to use 220 volts for the contactor coil which will be easy to run through the level control switch. But my real concern is about the best way to wire the pump control box to the contacts in the contactor. 

[Crossy]

@thaisail what you are suggesting sounds fine.

 

Use two of the contacts on the contactor to bypass the pump switch, mind you don't accidentally bypass the thermal overload trip too.

 

Alternatively, you could use the contactor to feed the existing supply input to the pump (leaving the pump switch "on") and bypass the float switch at your contactor box for manual control, may prove easier to get all the wires in.

 

[MajorTom]

Yeah, i would leave the control box as it is and control the existing mains with the contactor. Leave the internal switch on.

There is not a lot of space there, you would have drill and pull a couple of more cables into that purple box and force double wires into the screw terminals.

I assume you have an external box for the contactor. Just buy a simple switch and put it there for manual bypass of the float switch.

[thaisail]

5 hours ago, MajorTom said:

Yeah, i would leave the control box as it is and control the existing mains with the contactor. Leave the internal switch on.

There is not a lot of space there, you would have drill and pull a couple of more cables into that purple box and force double wires into the screw terminals.

I assume you have an external box for the contactor. Just buy a simple switch and put it there for manual bypass of the float switch.

Crossy agrees with you on this one! I will run the line and neutral from the CU to new contactor box. Then run the wires to the pump control box and leave the switch on the pump control box on all the time when I am connected to the float switch. When I want to fill the pond I will bypass the float switch control wire with a manual/auto switch.