Automation unit pressure adjustment adjustment. How to adjust the water pressure switch for the pump? Dry running protection

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It may need to be adjusted - adjust the on and off pressures. By default, it has factory settings, you can clarify them in the device passport, usually they are set something like this: turning on the pump at a pressure below 1.4-1.8 bar and turning it off at a pressure above 2.5-3 bar.

To adjust the pressure switch, you first need to know the desired settings for its operation. They must be determined at the calculation stage plumbing system and selection of pump and accumulator. To configure, you need to remove the relay housing.

Two springs are responsible for adjustment:

The larger one regulates the response pressure and is marked on the relay itself as P
The small one regulates the difference between the cut-in and cut-out pressures and is designated as ΔP

The regulators are two nuts that set the degree of compression of each spring: rotating the nut clockwise (twisting) compresses the spring and increases the value. To increase the activation pressure, you need to tighten the nut of the large spring, and to decrease it, loosen it. To increase the difference between the on and off pressures, you need to tighten the nuts of the small spring, and to reduce it, loosen it.

A pressure gauge is used to monitor how much pressure is produced by the adjustment.

How to set up a pressure switch?

Open the tap to start drinking water. The pressure gradually drops until the pump turns on. The pump activation pressure can be recorded using a pressure gauge.
Close the tap and wait until the pump turns off. The pressure switch will turn off the pump when the pressure reaches maximum. Using a pressure gauge you can determine this value.
If it turns out that the switching pressure that is required in the relay settings is not set, adjust it by rotating the nut of the large spring. You need to increase it - tighten it, you need to reduce it - loosen it. It is better not to turn the nut more than one turn at a time.
Repeat steps 1, 2 and 3 until the desired cut-in pressure is set.
If it turns out that the shutdown pressure does not correspond to the desired one, then adjust it by rotating the nut of the small spring. To increase the shutdown pressure, tighten the nut; to decrease, loosen it.
Repeat steps 1, 2 and 5 until the desired shutdown pressure is set.

After completing the settings, put the relay housing back on.

How does a pressure switch work?

The pump pressure switch is spring block, providing transmission of the signal received from the membrane receiving water pressure to electrical contacts that close and open the electrical circuit.

During operation of the pump, the accumulator is filled, the pressure in it increases, which leads to stretching of the pump relay membrane. The membrane presses on the spring block, the springs are compressed, which leads to the opening of the contacts of the electrical circuit. The pump is disconnected from the network and stops.

As water is consumed, the pressure in the accumulator decreases, which leads to a decrease in the deformation of the membrane and a decrease in its pressure on the spring block. The springs weaken and close the contacts of the electrical circuit. As a result, the pump turns on and the process repeats completely.

The standard pressure switch setting is in the range from 1.4 to 2.8 bar. At the lower limit (1.4) the pump is switched on, at the upper limit (2.8) it is switched off. Such a wide pressure range results in the pump being turned on frequently. You can increase the rest period of the equipment by adjusting the pump relay. But you will have to start work with a hydraulic accumulator.

Adjusting the pressure in the accumulator

The operation of the pump relay directly depends on the pressure in the hydraulic accumulator installed in the system. Therefore, before changing the settings in the relay, the battery is disconnected from the water supply network, having previously de-energized it. Then the water is completely drained from it and only then the pressure is measured. To measure, you can use a car pressure gauge, which is used to check tire pressure.

The pressure norm is 1.5 atm. If this indicator for the hydraulic accumulator is lower, the pressure level is increased by pumping up the hydraulic accumulator with the same car pump.

The hydraulic accumulator is ready, you can change the relay settings.

Relay settings

To do this, the pumping station is reassembled and put into operation. Pressure adjustment is carried out with the equipment running. To do this, use two adjusting screws located under the cover of the device’s automation group. Adjustment of the switching pressure level and switching pressure is carried out separately.

The sequence of actions is as follows.

The activation of the pump is detected. In this case, the pressure in the water supply system is measured.
The station is disconnected from the power supply network
Removing the relay cover
The screw with the corresponding marking is adjusted (loosened or vice versa tightened)
The pressure in the water supply network decreases (you need to open the tap and drain some of the water)
The pumping station is put into operation. In this case, the new pressure at which the pump starts working is measured.
If the switching pressure does not correspond to the desired one, the process is repeated again.

As you can see, you can adjust the pump relay yourself, without the help of specialists.

Another device that provides the nominal pressure in your water supply is correct work pump, water supply, is a pressure switch. Based on the name, we can directly conclude that this node provides control over the pressure in the system and reacts by turning on and turning off electrical contacts in case of deviation from the nominal set pressure, within the limits established when setting it up. In this article we want to talk in more detail about the purpose of the pressure switch, the features of its installation, settings and characteristics.

Application of pressure switch

So, we have already briefly mentioned what a pressure switch can be used for. However, if we talk about specific application cases, these include the use of a pressure switch to prevent the “dry running” mode of the pump, which we wrote about in our other article (“Protection against “dry running” for a well pump using a relay pressure").
The pressure switch also maintains pressure in the receiver pumping station. As a result, at the outlet, in our tap, we have a stable, constant flow of used water.

Pressure switch characteristics

The main characteristic of a pressure switch is its nominal operating pressure. Yes, there is a certain tautology in the previous phrase, but it is precisely this that is fully accurate for describing main characteristics relay, since dimensions, weight, connecting threads are additional parameters. So, the operating nominal pressure of a pressure switch is an indicator selected from a possible range. So today, according to GOST 26005-83, there is the following operating range (controlled pressure mPa (kgf/cm)) for pressure switches:
- 6,3 (63),
- 10 (100),
- 20, (200),
- 32 (320).

In fact, based on market needs and other standards, you may well find pressure switches with other operating (control) pressure characteristics. The characteristics of the pressure switch also include:

Connecting thread;
- dimensions;
- mass;
- moisture and dust protection class (IP);
- rated current and voltage for switched contacts;
- requirements for the working environment (water, refrigerants, etc.);
- temperature working environment;
- pressure switch version (built-in sensor or remote)

All this must be taken into account when selecting a pressure switch for each specific case.

Installation (installation) of a pressure switch

Here, so as not to be “sprayed” on possible options and conditions, of which there can be many, we will give an example for a specific case, for the RDM-5 relay. Installation and installation of the relay can be divided into two stages. The first is a mechanical connection and the second is an electrical connection. The mechanical installation of the RDM pressure switch is carried out using a tee fitting, a control pressure gauge and a FUM tape, which is used for sealing threaded connections(on the relay there is a 1/4 inch internal thread). A photo of the assembly ready for installation in the pipeline is shown below...

Electrical connections aren't that complicated either. The first step is to remove the relay protective cover. Under it you will find 4 contacts, two “input” and two “output”. In the figure below, the electrical supply input is (L1,L2) and the pump output is M

The cross-section of the supply wires must correspond to the power of the electric pump. The socket must be grounded. Grounding must be connected.
As a result, we get the following diagram connections for electrical and mechanical parts...

Let’s say right away that such a connection scheme for a pressure switch does not provide protection against “dry running”. Protection against “dry running”, in case all the water is pumped out of the well, will only work when the pump is positioned higher than check valve, that is, it enters the pressure control circuit of the relay. But for this case, not a submersible pump is required, but a surface one. In general, this is a slightly different option, although it also has the right to be implemented. See picture below...

Design of a pressure switch (principle of operation)

Structurally, most pressure control relays are contacts spring-loaded by a plate, which is subject to the operating pressure of the medium. The influence of the plate, the switching on and off of the contacts is regulated by changing the stiffness of the spring, which is a direct link that ensures the dependence of the switching on of the contacts. This screw and spring provide a lower limit for the relay to operate. Also, in most cases, there is an adjusting screw with a spring, which provides a spread in the operation (switching on) of the contacts. This screw adjusts the upper limit of the relay operation. Next we will talk about setting up the pressure switch after installation in the water supply system.

Setting (adjusting) the pressure switch

Based design features, which we talked about earlier, we actually have to configure the relationship, the rigidity, between the platform that is affected by the working pressure and the contacts that should be turned on. These adjustments are made by changing the stiffness of the spring, which is actually either compressed or weakened by adjusting nuts. So the factory settings for the RDM 5 relay (as, by the way, for many others) will be as follows. The minimum response pressure is 1.4 atmospheres, the maximum, which is set using a differential nut, is 2.8 atmospheres. If you need other relay response parameters, then to increase the level of the lower limit of contact pressure response, tighten nut 2 clockwise.
Please note that as the lower level increases, the upper shutdown level automatically increases. The difference between them will be 1.4 atmospheres. When setting up, it is necessary to comply with the condition that the switch-off of the pressure switch must always be lower than the maximum possible pressure produced by the pump. Otherwise, the pump will never turn off, and in the end it will simply burn out. For example, it turned out that the shutdown pressure became 4 atmospheres. This means that the lower one will be 4 - 1.4 = 2.6 atmospheres, that is, we raised it from 1.4 to 2.6. Nut 1 is designed to adjust the difference between the minimum and maximum response pressure. In our case, with factory settings, this difference is 1.4 atmospheres. If we tighten the nut, we will increase the difference (for example, instead of 1.4, it will become 2). As a result, differentiated pressure will need to be added to the lower limit, that is, 2.6 + 2 = 4.6.
It turns out that together with the adjustment differential pressure We are also changing the upper pressure cut-off limit. Take this into account when making adjustments. Remember that the maximum pump shut-off pressure should not be higher than the maximum produced by the pump itself. The settings for reducing the minimum pressure and reducing the differential pressure are directly opposite, that is, nuts 1 and 2 must be unscrewed.
If you try to describe the setting and adjustment of the pressure switch using graphs, you will get the following diagram...

Imagine that to get water at your dacha you can simply open the tap. That there is no need to fill containers with buckets for basic hygiene procedures, cooking, and cleaning. To do this you just need to install pump equipment with a pressure sensor, but first you should understand its structure, don’t you agree?

Our article will introduce you in fine detail to the pressure switch for the pumping station. You will learn how the device works, how it activates and stops pumping. We describe in detail the popular options for pressure sensors and how to adjust them.

The material lists technological nuances and relay configuration methods. The information presented is ideally complemented useful diagrams, photo and video applications.

The device, small in size, belongs to the group of automation systems servicing pumping equipment. Its functionality is only possible in conjunction with a hydraulic accumulator.

Despite its small size, the relay performs a number of important functions:

allows all devices to function in the specified mode;
Reacts sensitively to changes in on/off thresholds;
activates and stops the pump when critical values are reached.

Simply put, it regulates the automatic process of pumping water in independent water supply schemes with membrane tank. The adjustment is made during the switching of electrical circuits when two pressure parameters are reached in the system, accepted as the upper and lower limits.

Design and principle of operation

The pressure control relay has a simple dismountable design, thanks to which the user can independently adjust the operation of the accumulator, narrow or expand the parameters.

Internal parts are arranged in a durable plastic case, resembling an irregularly shaped box. It has a smooth surface and only 3 external working elements: two coupling clamps for electrical cables coming from the network and the pump, and a ¼, ½, 1 inch metal pipe for connecting to the system. The thread on the pipe can be either external or internal.

The contacts of two electrical circuits, closed when the maximum pressure parameters are reached, are located under the springs, which are fixed to metal plate. When the pressure increases, the membrane of the hydraulic tank is deformed, the pressure inside the bulb increases, and the mass of water presses on the plate. That, in turn, begins to act on a large spring.

When compressed, the spring is activated and opens the contact that supplies voltage to the motor. As a result, the pumping station is switched off. With a decrease in pressure (usually in the range of 1.4 - 1.6 bar), the plate returns to its original position and the contacts close again - the motor begins to work and pump water.

When purchasing a new pumping station, it is recommended to test the equipment to ensure that all components. Examination performance qualities the relay occurs in the sequence outlined below. As an example, the Haitun PC-19 model.

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Dry running alarm

Mechanical models do not have an indication or control panel, but they can be equipped with a forced activation button. It is necessary to make it function.

Criteria for selecting a relay for a pump

There are many universal models that are sold separately from pumping stations and can be used to assemble a system with your own hands. When purchasing a relay or automation unit, you must rely on the characteristics of the device. They can be found in the technical documentation.

It is important that the relay’s capabilities match the characteristics of the rest of the equipment.

The pump stopped turning off

In this case, we forcibly turn off the pumping equipment and proceed in the following order:

We turn it on and wait until the pressure reaches its maximum level - let's say 3.7 atm.
We turn off the equipment and lower the pressure by draining water - for example, to 3.1 atm.
Lightly tighten the nut on the small spring, increasing the differential value.
We check how the cut-off pressure has changed and test the system.
Setting it up best option by tightening and loosening the nuts on both springs.

If the reason was due to incorrect initial settings, it can be solved without buying a new relay. It is recommended to regularly, once every 1-2 months, check the operation of the pressure switch and, if necessary, adjust the on/off limits.

Situations that do not require adjustment

There can be many reasons when the pump does not turn off or turn on - from clogged communications to engine failure. Therefore, before you start disassembling the relay, you should make sure that the rest of the pumping station equipment is working properly.

If everything is fine with the other devices, the problem is in the automation. Let's move on to inspecting the pressure switch. We disconnect it from the fitting and wires, remove the cover and check two critical points: the thin pipe connecting to the system and the contact block.

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If cleaning measures did not help, and adjusting the position of the springs was also in vain, most likely the relay is not subject to further use and should be replaced with a new one.

Suppose you come across an old but working device. Its adjustment occurs in the same order as setting up a new relay. Before starting work, make sure that the device is intact, disassemble it and check that all contacts and springs are in place.

Conclusions and useful video on the topic

Practical video tips will help you better understand how to adjust a new pressure switch at a pumping station if the parameters do not suit you for some reason. You will also learn how the dry running device differs.

Professional tips for proper adjustment:

Comparative characteristics of two types of relays:

Specialists are usually not invited to correct the operation of the pressure switch, since this is a simple procedure that takes little time. You can leave the factory settings, but even minimal adjustments will help extend the life of the pump and hydraulic tank, and also optimize the operation of the station.

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