Choosing a Standard Pressure Switch for Submersible Pump Without Reservoir: Omnigen vs Alledrogo

Good day.
I would like to use a pressure switch for a submersible pump not equipped with a hydrophobic tank and I have a problem with choosing this switch.
I noticed that for pumps without a hydrophobic tank there are other switches that protect against dry running.
I have a sensor in the pump installation that protects it from working when the water level drops below a certain level. In this situation, can I use a standard pressure sensor without dry running protection?
Let's say omnigen with alledrogo for 20-30 PLN.

Why don't you install even one of the smaller diaphragm tanks? You will have greater comfort of use.

Is the submersible pump built into a traditional dug well or is there a borehole? If it is a dug well, it is possible to install a float switch. during installation in the switching station, such a configuration that the pump, when the water level falls and the float drops to a certain position, switches off when the float switch is activated and the pump should be switched on manually after some time.

Kierbedz4 -Ariel N. has a dry-running protection installed.

I have installed probes immersed with a pump - why a float?
I have a tank at home for the needs of a house tube to be an extra leg. I don't want to go into details, the whole installation is too extensive.
I would like to find out if the switch mentioned above in the section without a tank (because the section operated by him does not have one) will be fine.
And find out if the only difference between cheap switches and those dedicated to installation without a tank is that the dedicated ones have a water flow sensor and protect against dry running, because if that's the only difference, I already know everything I wanted.
Btw the well is not dug, it is drilled. I dipped 3 probes with the pump. One under the pump, the second one a bit above and the third one much above.
When the mirror drops below 2, it cuts the power to the power supply until it reaches 3.

And what is the pressure stored in by a switch dedicated to work without a tank?
Pump - pipe - sensor - tap?

The point is that when the timer opens the solenoid valve for irrigation, the pump is to start. When the timer closes the solenoid valve, the pump is to stop. The start signal for the pump is to be a pressure drop. Why the pressure drop and not the valve opening impulse?
Because when the valve jams, the pump will work without draining.
Why without a hydrophobic tank - because the capacity of the bed is sufficient for continuous pump operation and there is no room for a tank in the coils.
Not ready set because the supply pipe is 1 1/2 inch and sets usually max 1 inch.

I would just like to avoid a situation where the pump starts every second every second.

The question is posed in the last paragraph: Can I use an ordinary sensor without dry running protection in this situation? The answer is short. No, the dry-running sensor must turn off the pump when the water drops to a minimum of half a meter from the water inlet to the pump and if the sensor you write about will work with a delay, in this case I do not know what bearings work in the pump because for 30 years of work with the above-mentioned pumps, There were bearings in the form of rubber, where the hole in the rubber sleeve in which the rotor sleeve worked was hexagonal due to the quick lubrication with water. When the pump was running on dry running, the sleeve installed on the rotor shaft was seized because the rubber bearing on the sleeve melted and the details were vulcanized. you shouldn't check without lowering it into the water.

I know so much about the pump:
Submersible Pump SDM Premium - PLN 679 gross (diameter 99mm) IBO
Construction
Rotors, diffusers: - Reinforced polymer - (much better rotors)
better shaft sealing.
Pump housings: - stainless steel
Pump shaft - stainless steel
Filter mesh - stainless steel
longer cable 18m (longer cable)
Cable sheath - stainless steel
Mounting screws - stainless steel
Clutch - stainless steel (new clutch model)

- capacity max - 105 l / minute = 6.3 m3 per hour
-pressure max 6 bar

Added after 6 [minutes]:

Okay, and what protects the pump from running dry if I have a tank and a cheaper switch?

The second probe is more than one meter above the third pump 6 meters

Ok, I agree - the pump cannot run dry.
Therefore, in the configuration, the pump without a tank has a switch with a flow analysis function.
But why then the second set is a tank with a simple contact?
Now what, throw the probes in the trash?
Because I can not understand why this more expensive switch if the probe cuts off the pump? These switches operate for a few seconds and the probes for a few ms

Ariel N. wrote:

Now what, throw the probes in the trash?

Absolutely not. Just put that extra pressure switch (it's not expensive) on this "leg". If it turns out that it meets the requirements you expected, it is good. If not, you will install a more expensive hydrophore machine.

The problem of this hydrophore unit is not only the price, because it will get over the PLN 80 more. The worst thing is that they have a 3/8 inch connection and this is a failure with this number of sprinklers.
So I will put on the cheaper one and lead the wires to the bulb above the wells. Its lighting will signal the operation of the pump, if I have a disco at night, I will break the contact.
You drew my attention to a quite important point - the water is not springy, I will also give a tee that the blind tube points upwards.

If you give the tank, the pump will switch on depending on the pressure on the tank on which the pressure switch is built-in with the appropriate parameters switch on-switch off. You can problem with these probes on one probe. with a long enough cable built into it i After installing the tank, the pump will turn on periodically as the pressure in the tank decreases. Note that the motor of the submersible pump runs at 2800 rpm

Ariel N. wrote:

The problem of this hydrophore unit is not only the price, because it will get over the PLN 80 more. The worst thing is that they have a 3/8 inch connection and this is a failure with this number of sprinklers.

Why are there 1 "even on Ale ...

The output goes 1 1/2 inch and reducing this diameter in front of the divider is not an option.

The author of the post is making a stir on the forum once again.