control 2 switching wells

[Thomas Schuett]

have a well for use domestic water and irrigation in operation but the water is to iron. So I have to filter the water.
One way to realize this, is to use the earth as the filter.
Therefore I need to add oxygen in a subset of the pumped-up water and bring it back into the well (which is no problem).
In the well it is distributed in the earth, where it starts a chemical process that the iron is bound there.
This regeneration phase use some times and is too long in my case for using only 1 well (the water requirement >40 m3/day).
So I need 2 wells with 2 pumps, 2 back water pipes and (hopefully) 1 control.

The principle is simple:
odd days: well „A“ is the working; well, „B“ is regenerating
even days: well „A“ is regenerating; well „B“ is working

At present, the deep well pump with 2.2 kW, 400V is switched directly via a pressure switch MDR-5 and a contactor.
The irrigation is controlled via Opensprinkler AC (HW 2.1).
So the back water pipe could be (time)controlled via 2 valves connected to the OS and programmed as two separated stations.

But how can I control the two pumps in conjunction with one pressure switch ?
Here I am still looking for a solution and hope for some hints & tips.

[Ray]

Hi, I need some more explanations about the system setup. My understanding is that you want to have one pressure switch to work with two pumps. I am not sure how the pressure switch works, and how it’s wired to the pump. A picture or drawing would be ideal to visualize the setup.

[Thomas Schuett]

I hope I found a solution:

The pressure switch switches at present directly the well pump.
The idea is that it will turn on 4-phase impulse switching relay.
To this relay both pumps are connected (4-wire, 380V, each connected as a group).
In addition, this relay is connected via the 24V control line directly to the Opensprinkler.
For the OS, the relay is an irrigation section, which e.g. is turned off on even days, and on on odd days.

If the pressure switch now detects a vacuum the current is switched through to the switching relay.
The relay drops the stream then passed to the respective pump.
If the pressure switch detects no vacuum, the relays is without electricity.
In this case (it´s a failure of the supply voltage for the relay) the switch power off defined.
Here, the circuit state could be changed.
But next time the relay is switched on, the OS control would work again and switch to the correct circuit/pump.

The impulse switching relay is a Eltako ESR12Z-4DX-U

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