To find out which is stronger - a water hose, pipes or a pump, you can assemble a water supply system without a pressure switch. In all other cases, when supplying water to a house, a device is built into the system that replaces the manual switching on and off of the supply voltage of the submersible pump.

Individual water supply at home cannot be imagined without a relay that allows you to automatically turn off the pump as the water supply system is filled with water and turn it on after the water is consumed.

Fig. 1 Constructive execution pressure switch

Structurally, a standard pressure switch for pump control is as follows. The plastic case contains terminal blocks for connecting the power cable and the mechanical control system of the device with adjusting spring struts, outside there is a 4-inch pipe for connecting to the water main. The supply cable enters and exits the pressure switch through two wide inlets, the wires are clamped with a plastic ferrule nut.

In the normal state, the contacts are normally closed and the connected device powers the pump motor. With an increase in the pressure in the system, water acts on a rubber membrane with a piston installed at the inlet of the water pipe of the device. In turn, the diaphragm piston presses on a movable metal platform, which is hinged inside the device body at one point. The platform plate rises and opens the electrical contacts, when the pressure drops, it returns to its original state, closing the contacts.

A screw with a spring and a nut is installed in the center of the device, which sets the distance of the contact plate to the diaphragm piston - if it is less, the device is triggered at a lower pressure, the increased distance will require more movement of the piston with the diaphragm to affect the contact pad, which is equivalent to an increase in pressure in the system.

At some distance from the main adjusting screw, a second adjusting screw with a smaller spring is placed. It sets the range of movement of the contact metal pad, setting the difference between the pressure, making and breaking contacts. Thus, the large adjusting screw sets the lower response threshold of the device (pressure to turn it on), the small one adjusts the range of the device response to shutdown (adjustment depth).

Rice. 2 Connection diagram

Relay adjustment

Upon purchase, the relay is configured for a certain switching mode, the standard values ​​are 1.4 and 2.8 atm., That is, at 2.8 atm. the pump will be turned off and turned on if the pressure is less than 1.4 atm. Usually, when installing a device in a system, a selection of the response threshold is needed - for this you need to know what pressure the pump gives in the well.

If the pressure borehole pump 2 atm., And the standard value of 2.8 atm remained in the relay, then the pump will never turn off (it physically cannot create a pressure that reaches the response threshold) and after intensive work will go to eternal rest. A less tragic situation is when the pump can deliver a head of 5 atm., And the relay turns it off at 2.8 atm. In this case, the system works ineffectively and it is desirable to install a device corresponding to the pressure of the borehole water pump.

For measurements when adjusting the relay, a pressure gauge is required, the work consists of the following stages.

• Water is being drained from the system, and the pump activation pressure is recorded on the pressure gauge.
• The taps are closed and the pressure gauge readings are recorded at which the pump is turned off.
• Adjust the device with a large screw, periodically turning on and off the water until you get desired value lower pressure.
• Then proceed to adjust the range that sets the upper pressure with a small screw. Water is also periodically turned on and off until the required value is obtained.

Connecting the pressure switch to the water supply system

When installing a relay in a water intake system, the following rules should be observed.

Rice. 3 Wiring diagram of a submersible pump to a hydraulic accumulator

• The accumulator for water supply systems and the point of connection of the device to the water supply are located nearby - this will avoid switching the pump during sudden short-term surges in pressure.
• When installing, take into account temperature regime- some models function only in warm conditions.
• To simplify installation in modern pumps a surface type fitting is installed, to which a relay and a pressure gauge can be directly connected.

Connecting the pressure switch to submersible pump can be done in two ways:

1. The device connects to water pipes through a tee by means of an adapter fitting.
2. Before connecting the accumulator to the submersible pump, a five-way fitting, connected devices (accumulator, pressure gauge, relay) and water main connect at one point.

Review of popular models

Pressure switches are of two types: mechanical and electronic, the latter are much more expensive and rarely used. A wide range of devices from domestic and foreign manufacturers is presented on the market, making it easier to choose the required model.

RDM-5 Dzhileks (15 cu) is the most popular high-quality model from a domestic manufacturer.

Fig. 4 RDM-5

Specifications

• range: 1.0 - 4.6 atm .;
• minimum drop: 1 atm.;
• working current: maximum 10 A .;
• protection class: IP 44;
• factory settings: 1.4 atm. and 2.8 atm.

Genebre 3781 1/4 ″ ($ 10) - budget model Spanish production.

Rice. 5 Genebre 3781 1/4 ″

Specifications

• body material: plastic;
• pressure: top 10 atm .;
• connection: threaded 1.4 ";
• weight: 0.4 kg.

Italtecnica PM / 5-3W ($ 13) is an inexpensive device from an Italian manufacturer with a built-in pressure gauge.

Rice. 6 Italtecnica PM / 5-3W

Specifications

• maximum current: 12A;
• working pressure: maximum 5 atm .;
• bottom: adjustment range 1 - 2.5 atm .;
• upper: range 1.8 - 4.5 atm.

Pressure switch - essential element in the water intake system, which provides automatic individual water supply to the house. It is located next to the accumulator, the operating mode is set by means of adjusting screws inside the housing.

More details electrical circuit the connection of the pressure switch and everything connected with it has been considered by us.

So, as you can see from the diagram, a three-wire supply cable is connected to the pressure switch single-phase network (phase, zero and ground), and a similar cable is already coming out of the relay to the pump that pumps water into the system. Of course, there are also three-phase devices and a water pressure switch is used appropriately, but in everyday life, a single-phase one is usually sufficient.

In the water supply of a private house, single-phase surface or submersible pumps are most often used, pumping water from a well or a well. Electric power pumps vary greatly depending on the required performance of a particular device under specific operating conditions.

Usually, the power of such a domestic pump does not exceed 1.5-2 kW, accordingly, to connect it, a cable with a cross-section of 1.5 sq. mm is required. and a 10 Ampere line circuit breaker.

Connecting the pressure switch to the mains is usually one of two options., each of which has its own strengths and weaknesses:

1. Near the place of installation of the pressure switch, on the wall, an electrical outlet is mounted for it. A cable is connected to the relay itself with electric plug at the end.

This is a universal, most often the most convenient, connection option. The main disadvantage of this method is the need extra costs to the outlet device itself, as well as possible problems at the junction, in the vicinity of the water supply system of the house.

2. The second option is the simplest and therefore the most reliable. At the place where the pressure switch is installed, a power cable is led out of the wall, with which the relay is connected to the network. In this way, maximum connection reliability is achieved, since The housing of the pressure switch, like the cable entry into it, is usually hermetically sealed and they reliably protect the point of contact from possible adverse effects.

The main disadvantages of this method include increased requirements for the accuracy of the choice of the location of the output and the length of the cable, as well as some possible complexity in subsequent maintenance. It is always easier to unplug the appliance than to disassemble and disconnect the wires.

In our installation example, the second option is selected - a cable coming out of the wall. The maintenance problem was solved by installing a separate circuit breaker for the pressure switch in electric board boiler room.

Before connecting the power cable to the relay, make sure that there is no voltage at the installation site!

We proceed directly to connecting the pressure switch to the network, on the example of the Italtecnica TYPE PM / 5G model.

First of all remove the protective plastic casing, for this you need to use a straight screwdriver (slotted), unscrew the fasteners, as shown in the image below

Then In the pressure switch, the supply cable and the cable leading to the pump are laid through the cable glands.

This model uses standard sealed cable glands familiar to many. To fix the cable in them, you must first unscrew the plastic nut, then insert the cable first into it, and then through the input, inside the relay and at the end tighten the nut to the stop.

Then, having previously prepared - removing the protective insulation, we connect the cores of the cables to the relay terminals pressure according to the following diagram.

Do not pay attention that one of the connected cables in the diagram ends with an electric plug, in our case, instead of it, a power cable is connected, which goes continuously to the electrical panel.

After connecting the wires and checking all the terminals, you should get something like this:

This completes the connection., it remains only to carefully put the protective cover back on and fasten it.

Now, by turning on the electricity supply, you can check the operation of the water pressure switch and adjust its operation.

As you can see, there is nothing difficult in installing a relay, especially if you clearly understand the principle of its operation.

If you still have any questions about connecting the pressure switch to the mains, for example, you have a more powerful pump or it is three-phase, or just another relay model, or do not know how to connect and which cable and outlet to use, be sure to leave them in comments to the article, I will try to answer everyone promptly.

The PM / 5-3W pressure switch is made in Italy. Used to create automatic water supply systems both in the private sector and small industrial production... Has excellent performance characteristics and a number of innovations that make it possible to successfully use this device to control the water pressure in the system.

Peculiarities
- Applicable for single phase pumps.
- Long term service
- Durable plastic housing
- The presence of a built-in pressure gauge
- The presence of three 1 ”outlets allows you to connect a pump, a hydraulic accumulator and a water outlet line.

Specifications

• Mains voltage - 230 V, 50 Hz.
• The maximum power is 1500 watts.
• Maximum switched current - 12A.
• The maximum working pressure is 5 bar.
• Switch-on pressure regulation range - 1 - 2.5 bar.
• Switch-off pressure regulation range –1.8 - 4.5 bar.
• Hydraulic connection - 1 "np x 1" time x 1 "time.

Connection diagram

This pressure switch is in great demand due to its high quality and successful design - the possibility of connecting three unions and the presence of a pressure gauge. Maximum effect operation of the device is achieved with the presence of a hydraulic accumulator. Which avoids sharp changes pressure.
We recommend using to create automatic system water supply at home or summer cottage.

How to buy pressure switch PM / 5-3W

You can buy a pressure switch by making a purchase directly on the website of the online store, or by calling the phone in the Contacts section. Our manager will contact you and arrange delivery or reserve the goods for pickup.

If you need a pressure switch in Moscow, delivery within the city and in the nearest Moscow region is at your service. For buyers from other regions of Russia - delivery of any transport company or the postal service as agreed.

Payment for goods is carried out in the following ways:

1. Payment in cash.

When picking up from the store, or when receiving the goods to the courier.

2.Bank transfer - payment according to the invoice for payment as for legal and for physical persons.

When placing an order, select a payment method: "Bank Transfer".

After confirming the order, our specialist will contact you and after agreeing on all organizational issues you will be sent an invoice by e-mail, which you can pay at any bank or via an internet client.

1. Pickup.

Pickup time and terms:

PVZ metro Sokol: you can pick up the order the next day after ordering from 10 to 18 on weekdays. The order is stored at the pick-up point for 3 business days.

Pickup cost:free of charge when ordering from 1,000 rubles. (when ordering less than 1,000 rubles - the cost of pickup is 80 rubles.)

Attention! At the point of issue of orders there are only pre-reserved goods!

The employee of the pick-up point does not give any advice on the goods!

Driving directions to the pickup point is located on the page CONTACTS

2. Delivery in Moscow within the Moscow Ring Road

The following items are delivered free of charge:

Kerosene heaters of the "Sengoku" trademark

Cost of delivery:

If your order weighs more than 20 kg - the manager will calculate and inform you the cost of delivery additionally!

Time of delivery:

Delivery is carried out on weekdays from 10:00 to 20:00.

Per 30-90 minutes the courier calls you and agrees exact time arrival.

Exact delivery address (city, street, house number, apartment or office number, intercom code)

The contact person

Contact phone numbers

3. Delivery outside the Moscow Ring Road and further across the Moscow region

Cost of delivery:

If the WEIGHT is not indicated in the product card, you can check it with the manager.

If your order weighs more than 20 kg - the manager will calculate and inform you the cost of delivery additionally!

Time of delivery:

Delivery is carried out within 1-3 working days from 10:00 to 20:00 without reference to half a day.

Per 1-2 hours before delivery, the courier will call you and agree on the exact time of arrival.

What is important to indicate when ordering:

Exact delivery address ( city, district, settlement, street, house number, apartment or office number, intercom code)

The contact person

Contact phone numbers

4. Delivery to the regions of the Russian Federation

We can send you goods from any of the following companies.

CDEK - www.cdek.ru

First Forwarding Company (PEK) - www.pecom.ru

The estimated cost of delivery of goods can be found on the websites of these companies or contact our specialist.

What is important to indicate when ordering:

Passport series and number, date of issue

Full Name

Receiving city

If none of the above methods suits you, we will send the goods to your address in another way - as agreed with you.

Good afternoon, dear readers of the blog site

In the "Accessories" heading, we will consider a pressure switch, which controls the operation of automatic pumping stations as well as superficial , or, if they are used in conjunction with... By using pressure switch you can configure an autonomous water supply system, an irrigation system or fire extinguishing system for the required tasks.On sale presented pressure switch RM-5, RM-5G, RM-12 made by an Italian companyItaltecnica.The main difference between the product PM-5 from PM-5G in that the latter uses a union nut with a connecting size 1/4 ″. The RM-5G relay is more convenient for installation.

The main characteristics of RM-5 and RM-12 are shown in Table 1.

Specifications	RM-5	RM-12
1. Working pressure range (bar)	1-5	3-12
2. Factory setting of on and off pressure (bar)	1,4-2,8	5-7
3. Minimum pressure drop (bar)	0,6	1,5
4. Working environment temperature up to (° С)	55	55
5. Maximum working current (ampere)	16 (10)	16 (10)
6. Voltage (volts)	250	250
7. Connection internal thread(inch)	1/4	1/4

Table 1

Note: When using a pressure switch to control pumping equipment, the maximum switching current is 10 A.

Recently, the product RM-5G (25 A) with maximum switching current to control pumping equipment constituting 16 A.

Relay design

Structurally, the relay is assembled in a plastic case and closed with a cover. Figure 1 shows the main elements. To remove the top cover from the product, unscrew the plastic plug at its end using a slotted screwdriver.

Pressure switch device

1. Case - all elements of the pressure switch are located on it;

2. Connecting flange, used to connect the automation to the water supply system. The flange connection size is 1/4 "female thread. The flange contains the working chamber and the diaphragm. The flange and diaphragm are attached to the relay housing with four screws;

3. Nut for adjusting the pressure difference ΔP between the on and off pressure. The more we compress the spring (tighten the nut), the greater this difference will be;

4. Nut for adjusting the cut-out pressure of the relay. When tightening the nut, the shut-off pressure will increase, and when released, it will decrease. This rod also holds the top cover with a plastic plug;

5, 6. Terminals for connecting electrical wires;

7. Terminals for connecting ground wires from the power supply and the motor;

8. Cable clamping sleeves are used to rigidly fix the mains supply cable and the motor connection cable.

Pressure switch wiring diagram

In Fig. 2 shows a diagram electrical connection relay RM-5, RM-5G, RM-12.

Connection diagram for pressure switches PM-5, PM-5G, PM-12.

The circuit for connecting a relay to an electrical network is very simple. Wires are connected to terminals 5, 6 (see Fig. 1). Moreover, it does not matter which pair of terminals is input (connection ~ 220 V.), and which is output (connection to the motor). After connecting the wires, it is necessary to make sure that they are in reliable contact with the relay terminals, if necessary, tighten the contacts.

Operation, maintenance and adjustment of the relay

Pressure switch RM-5, RM-5G, RM-12 are very simple and reliable control devices autonomous system water supply. Subject to the operating conditions, they work without failures and failures for a long time and reliably. However, given the quality of our water, voltage fluctuations or high humidity, malfunctions occur. Incorrect operation of the automatics, as a rule, leads to the failure of the pump.

Let's consider the most common cases.

Hard water. In hard water or in water with a high iron content during operation, the passage to the working chamber is gradually "overgrown", or the chamber itself overgrows. The diameter of the passage is small, 5–5.5 mm. There may come a moment when the relay does not turn on or, on the contrary, does not turn off. To eliminate this defect, you need to clean the passage or the chamber itself by following these steps:

1. Disconnect the product from the power supply.
2. Relieve excess pressure by opening the water taps.
3. If the automatics are PM-5G, then using a 17 open-end wrench, unscrew the union nut and remove the relay. If the automatic equipment is PM-5, then it is necessary to remove the cover from the pressure switch by unscrewing the fixing cap with a slotted screwdriver, disconnect the cables from terminals 5, 6 and ground (Fig. 1), loosening the cable glands, disconnect the cables from the product using a wrench unscrew and remove the relay by 17.
4. Use a match or other blunt object to clear the blocked passage. You need to clean it carefully for two reasons: the first is from working chamber water can splash and the second reason is not to damage the rubber membrane. To clean the working chamber, it is necessary to unscrew the four screws securing the flange to the relay housing. Remove the flange and membrane (do not lose a special "penny" - a round metal plate with two ears during disassembly), rinse and clean the flange and membrane.
5. Assemble in reverse order. If the automatics are RM-5, then before installation, it is necessary to seal the threads with fum tape or special sealant.

High humidity. Very often, the station or automation is located in a pit. Lack of adequate ventilation leads to high humidity, and moisture leads to oxidation and burning of the contacts in the pressure switch. In this case, the automation starts to work unstably, turns on with a delay, or it turns on with a light tap on the body. If, when removing the cover, there is moisture on the surface of the product, and there are traces on the metal parts white bloom, the chances are high that the contacts are burnt. To repair such defects, you must contact the nearest service center, or call a service technician to the place of installation of the station or automation.

Voltage fluctuations also lead to unstable operation of the pressure switch. electrical network and entering the air supply system.

Pressure regulation. To adjust the pressure, there are two adjusting nuts and springs (Fig. 1). With nut 4 and a large spring, the system shutdown pressure can be adjusted. The more we compress the spring, the higher the pressure in the system, the automation will turn off. One of the most common causes of non-stop pump operation is an incorrect pressure switch setting. Before setting up the automation, you need to look at the operating parameters of the pump, namely, which maximum head he gives out. For example: the pump delivers a maximum head of 40 meters of water column or 4 bar (atmosphere). Theoretically, the maximum pressure for setting the relay can be 4 bar, but taking into account the fluctuations in the mains voltage, the gradual wear of the equipment, the maximum pressure for which we can set the automation is no more than 3.4–3.5 bar. Using nut 3 and a small spring, we adjust the difference ΔP between the pressure on and off the pump. The more we compress the spring, the greater the difference between turning the pump on and off. The smallest difference between the pressure on and off the pump is 0.6 bar for the PM-5 and 1.5 bar for the PM-12 relay - this is when the small spring is fully released. On the one hand, the difference between the on and off pressure must be set as small as possible in order to reduce the pressure drops. On the other hand, with a minimum range, the number of pump starts and stops increases, this problem is solved by increasing the volume of the accumulator. For optimal performance pumping equipment and an autonomous water supply system, it is necessary to choose the golden mean between the pressure on and off the pump and the volume of the accumulator. Additionally, you can see how to set up and adjust the pressure switch. If you have any questions, please write in the comments.

Thank you for your attention.