Water supply systems can be monitored and controlled by various parameters - water level, pressure, temperature. The most common is pressure control. One of the simplest and most popular elements of home automation in this case is the PM-5 pressure switch.

This relay is designed to control electric pumps for supplying water to the house. With the help of the RM-5 relay, the pump will work clearly in the set pressure mode. At the minimum pressure, the contacts close and the pump turns on, and when the maximum pressure is reached, the contacts open and the pump turns off.

The RM-5 pressure switch is produced by different manufacturers. Because of this, such relays may have slight differences in the type of housing and the location of the cable connection points.

There are varieties of pressure switches of this type with built-in pressure gauges, which simplifies their connection to the pumping station, since the number of threaded connections... Relays are also available with a special lever that allows you to manually open the contacts if it cannot turn off the pump on its own.

A general view of the RM-5 pressure switch is shown in the figure. Now let's see how it works.

This is a two-contact relay for switching electrical circuits, which is triggered by the pressure of the water in the system. Inside its body there are electrical contacts that are controlled by a membrane.

The pressure switch is most often connected to the pumping station using a special five-way adapter. In addition to the pressure switch, a pipe from a pump, a pipe from a water supply source, a hydraulic accumulator and a pressure gauge are connected to the adapter.

The pump pumps water into the accumulator. According to the readings of the pressure gauge, one can observe how the water pressure increases. The pressure switch automatically controls the activation and deactivation of the pump.

When the relay is connected to the adapter (connection size - 1/4 "), water presses on the membrane, which presses on the springs that control the electrical contacts. The relay contacts are connected in series with the pump motor and supply voltage to it.

The cable to the relay is connected through special sealed contacts. The operating voltage is 220 V. On the relay itself there are terminals marked "L" (Line), so it connects to them electrical cable that comes from the mains. A cable from the pump motor is connected to the terminals marked "M" (Motor). The terminal block also has grounding contacts for connecting the grounding conductors of the cables.

When connecting a water pressure switch to the pump, it must be remembered that the maximum switched current of its contacts is 10A (for some models - 16A).

The principle of operation of the PM-5 pressure switch is very simple. If the pressure in the system has dropped below the switch-on level (1.4 bar or a preset value), then the contacts will close and the relay will switch on the pump, and if the pressure in the system is higher than the switch-off level (2.8 bar or also a preset value) , the membrane presses on the springs, the contacts open and the pump will automatically turn off. When the pressure drops below the set value, the process is repeated.

Thus, the PM-5 pressure switch is used in order to automatically maintain the water pressure in the water supply system in the operating range of 1.4 - 2.8 bar (factory pressure settings) or 1 - 5 bar (manual settings).

These relays are configured at the factory to existing standards and norms. The settings, as a rule, do not need to be changed, because they are the most optimal. Sometimes it becomes necessary to configure the relay to its own, different from the factory parameters of operation. You can achieve the desired result in the adjustment by rotating the two clamping nuts in different directions.

To do this, you need to remove the cover from the relay. There are two nuts in the body - a large and a small one. The large nut can be used to set the cut-off pressure of the pump. To increase the response threshold, turn it clockwise and check the pressure. With the help of the second nut, you can change the difference between the pressure on and off the pump, both up and down.

All of these adjustments must be made using a pressure gauge. After adjusting the relay, be sure to close the cover.

Pressure switch RM-5 with built-in pressure gauge

The disadvantages of the RM-5 relay are that it has a rather complicated adjustment of the pressure thresholds. In addition, the water pressure in the water supply system is maintained in steps (the relay is activated only at the lower and upper limits). If the water in the well or well runs out, then it will not be able to turn off the pump. In the absence of water, the relay will be turned on until it can build up pressure, which can lead to pump failure. Therefore, the RM-5 water pressure switch must be used in conjunction with a liquid flow switch to exclude a "dry run" of the pump and its breakdown.

Good day. Consider the connection diagram of the PM / 5 mechanical pressure switch to the network and the pump. Let's take a look at the diagram first.

When you unscrew the top cover, you will see the following. First, a large screw with a spring for. It is marked with a large “P”. Second, there is a small screw with a spring for adjusting the difference of this parameter in the on and off mode. It is called delta P. Then there are two terminals for connecting the electric wire, called the word "motor". Two - "line". At the bottom - two for the ground connection. This looks like PM / 5 inside. The pressure switch is inexpensively sold in this Chinese store.

Pump connection to the mains

How do we connect the pump to the pressure switch and the mains? Three wires come out of it different color... Blue is zero worker or just "zero". Brown - "phase". Yellow-green - zero protective or simply "Earth".

Now let's see how they will "enter" the relay and how to "exit" from it. We push all three wires through a special hole in the case. We connect. Brown and blue in terminals labeled "motor". Yellow-green to ground. Then we bring the same wires to the power plug. Brown with blue, respectively, from the “line” terminals. Yellow-green from ground. All is ready. The PM / 5 pressure switch is connected to the pump and to the mains.

When organizing a water supply system at home, not only a pump is needed, but also automation to ensure its operation. One of the necessary devices is a water pressure switch. This small device turns on the pump when the pressure in the system drops and turns it off when the threshold value is reached. The magnitude of the on and off parameters can be adjusted. How this device works, how to connect it and how to regulate it - in the article.

Purpose and device

In order to maintain a constant pressure in the water supply system of a private house, two devices are needed - a hydraulic accumulator and a pressure switch. Both of these devices are connected through a pipeline to the pump - the pressure switch is located in the middle between the pump and the accumulator. Most often it is located in the immediate vicinity of this tank, but some models can be installed on the pump body (even submersible). Let's take a look at the purpose of these devices and how the system works.

A hydraulic accumulator is a container divided into two halves by an elastic bulb or membrane. In one there is air under some pressure, in the second water is pumped. The water pressure in the accumulator and the amount of water that can be pumped there is regulated by the amount of pumped air. The more air there is, the higher the pressure is maintained in the system. But at the same time, less water can be pumped into the container. Usually it is possible to pump no more than half of the volume into the container. That is, it will be possible to pump no more than 40-50 liters into a 100-liter hydroaccumulator.

For normal operation of household appliances, a range of 1.4 atm - 2.8 atm is required. To maintain such a framework, a pressure switch is required. It has two operating limits - upper and lower. When the lower limit is reached, the relay starts the pump, it pumps water into the accumulator, and the pressure in it (and in the system) rises. When the pressure in the system reaches the upper limit, the relay turns off the pump.

In a circuit with a hydraulic accumulator, water is consumed from the tank for some time. When enough has flowed out for the pressure to drop to the lower response threshold, the pump will start. This is how this system works.

Pressure switch device

This device consists of two parts - electrical and hydraulic. The electrical part is a group of contacts that closes and opens by turning the pump on / off. The hydraulic part is a diaphragm that exerts pressure on the metal base and springs (large and small) with which the pump on / off pressure can be changed.

The hydraulic outlet is located on back side relay. It could be an issue with external thread or with an American-style nut. The second option is more convenient during installation - in the first case, you either need to look for an adapter with a union nut suitable size or twist the device itself, screwing it onto the thread, and this is not always possible.

The electrical inputs are also located on the back of the case, and terminal block, where the wires are connected, is hidden under the cover.

Types and varieties

Water pressure switches are of two types: mechanical and electronic. Mechanical ones are much cheaper and are usually preferred, while electronic ones are mainly brought on order.

The difference in prices in different stores is more than significant. Although, as usual, when buying cheap copies, there is a risk of running into a fake.

Water pressure switch connection

The water pressure switch for the pump is connected to two systems at once: to electricity and water supply. It is installed permanently, since there is no need to move the device.

Electrical part

To connect a pressure switch, a dedicated line is not required, but desirable - there is a greater chance that the device will work longer. A cable with a solid copper conductor with a cross-section of at least 2.5 square meters must go from the shield. mm. It is desirable to install a bundle machine + RCD or difavtomat. The parameters are selected according to the current and depend more on the characteristics of the pump, since the water pressure switch consumes very little current. The circuit must have grounding - the combination of water and electricity creates an area of ​​increased danger.

Wiring diagram of the water pressure switch to

The cables are led into special glands on the rear side of the case. There is a terminal block under the cover. It has three pairs of contacts:

• grounding - the appropriate conductors are connected from the shield and from the pump;
• line or "line" terminals - for connecting phase and neutral wire from the shield;
• terminals for similar wires from the pump (usually on the block located above).

The connection is standard - the conductors are stripped of insulation, inserted into the connector, tightened with a clamping bolt. Pulling on the conductor, check whether it is securely clamped. After 30-60 minutes, the bolts can be tightened, since copper - soft material and the contact may loosen.

Pipeline connection

There is different ways connecting the water pressure switch to the plumbing system. The most convenient option is to install a special adapter with all required outputs - a five-way fitting. The same system can be assembled from other fittings, simply ready-made version always use flatter.

It is screwed onto a branch pipe on the back of the body, a hydraulic accumulator is connected to the rest of the outputs, supplying a hose from the pump and a line that goes into the house. You can also install a sump and a pressure gauge.

A pressure gauge is a necessary thing - to control the pressure in the system, monitor the relay settings. Mud sump - too desired device, but it can be installed separately on the pipeline from the pump. There is generally desirable a whole

With this scheme, at a high flow rate, water is supplied directly to the system - bypassing the accumulator. It starts to fill up after all the taps in the house are closed.

Adjusting the water pressure switch

Consider the process of adjusting the most popular instance - RDM-5. It is produced by different factories. The limits of the adjustments change, since different pressures are required in different sized water pipelines. This device leaves the factory with a basic setting. Usually it is 1.4-1.5 atm - the lower threshold and 2.8-2.9 atm - the upper threshold. If you are not satisfied with some parameter, you can reconfigure it as required. Such a procedure is usually necessary when installing a jacuzzi: a standard pressure of 2.5-2.9 atm is not enough for the desired effect. In most other cases, reconfiguration is not required.

The RDM-5 water pressure switch has two springs, which regulate the pump off / on threshold. These springs differ in size and purpose:

• large adjusts the limits (upper and lower at once);
• a small one changes the delta - the gap between the upper and lower boundaries.

The parameters are changed by tightening or unscrewing the nuts on the springs. If the nuts are tightened, the pressure increases; if they are loosened, it decreases. It is not necessary to turn the nuts strongly one revolution - this is a change of about 0.6-0.8 atm, and this is usually a lot.

How to determine relay thresholds

The pump activation threshold (and the lower pressure threshold on the water pressure switch) are related to the pressure in the air part of the accumulator - the minimum pressure in the system should be 0.1-0.2 atm higher. For example, if the pressure in the tank is 1.4 atm, the shutdown threshold is desirable at 1.6 atm. With these parameters, the tank membrane will last longer. But in order for the pump to work under normal conditions, look at its characteristics. He also has a lower pressure threshold. So, it should not be higher than the selected value (lower or equal). Based on these three parameters, you select the activation threshold.

By the way, the pressure in the accumulator must be checked before adjustment - there are significant deviations from the declared parameters. Under a removable cover (in different models it looks and is located in different places) the nipple is hidden. Through it, you can connect a pressure gauge (you can car or the one that you have) and see the actual pressure. By the way, it can be adjusted through the same nipple - increase or decrease if necessary.

The upper threshold - pump shutdown - is set automatically during adjustment. In the initial state, the relay is set to some kind of differential pressure (delta). This difference is usually 1.4-1.6 atm. So if you set the switch on, for example, at 1.6 atm, the shutdown threshold will automatically be set at 3.0-3.2 atm (depending on the relay settings). If you need more high pressure(raise water to the second floor, for example, or the system has many taps), you can increase the shutdown threshold. But there are limitations:

• The parameters of the relay itself. The upper limit is fixed and in household models usually does not exceed 4 atm. It just won't work anymore.
• The upper limit of the pump pressure. This parameter is also fixed and the pump should be turned off at least 0.2-0.4 atm before the declared characteristics. For example, the upper pressure threshold of the pump is 3.8 atm, the shutdown threshold on the water pressure switch should be no higher than 3.6 atm. But in order for the pump to work for a long time and without overloads, it is better to make a larger difference - overloads have a too bad effect on the operating time.

That's all for the choice of water pressure switch settings. In practice, when setting up the system, the selected parameters have to be adjusted in one direction or the other, because everything must be selected so that all the draw-off points work normally, including household appliances... Therefore, it is often said that the parameters are chosen by the "scientific poke" method.

Setting the water pressure switch for a pump or pumping station

Setting up your system will require a reliable pressure gauge that you can trust. It is connected to the system near the pressure switch.

The adjustment process consists in twisting two springs: a large and a small one. If you need to raise or lower the lower threshold (pump activation), twist the nut on a large spring. If you turn it clockwise, the pressure rises; counter-clockwise, it falls. Turn a very small amount - half a turn or so.

The sequence of actions is as follows:

• The system is started, the pressure gauge is monitored at what pressure the pump turned on and off.
• Apply or release a large spring.
• They turn on and check the parameters (at what pressure it turned on, at which it turned off). Both values ​​are shifted by the same amount.
• Make adjustments if necessary (re-adjust the large spring).
• After the lower threshold is set the way you want it to be, they begin to adjust the pump shutdown threshold. For this, a small spring is pressed or lowered. Do not turn the nut on it too much - half a turn is usually enough.
• Turn on the system again and look at the results. If everything suits you, they stop there.

What else do you need to know about adjusting the water pressure switch? That not all models have the ability to change the delta, so take a closer look when buying. There is a pressure switch for the pump in a moisture- and dust-protected housing. They can be installed in a sump, some models can be installed directly on the pump housing if it has such an outlet.

In some water pressure switches there is also an idle (dry) switch; in general, this device is in a separate case, but there are also combined ones. Idling protection is necessary so that the pump does not break if suddenly there is no water in the well or well. Some pumps have built-in protection of this type, for others they buy and install the relay separately.

Pressure switch Aquario type PC-5- a device that turns the pump on and off at certain pressure levels, the main control element for pump operation.

Principle of operation

The pressure switch is a block with springs responsible for the pressure limits. Adjustment is carried out with special nuts. The force of water pressure is transmitted by the membrane. It can weaken the spring (at a minimum) or withstand its resistance (at a maximum).

The impact on the spring leads to the opening and connection of the contacts in the relay.

The drop in pressure to the minimum limit closes the electrical circuit, energizes the motor and turns it on. The pump runs up to the maximum pressure, then the relay opens the circuit, the voltage is cut off and the pump is turned off.

The conventional pressure switch is adjustable from 1 to 8 bar.

Factory setting operates at 1.4 bar (minimum) and 2.8 bar (maximum) to switch off the pump.

Pressure regulation

There is a direct relationship between the volume of the accumulator, the settings of the pressure switch and the pressure of the water supply. Before setting the relay, check the air pressure in the accumulator.

1. The pumping station must be disconnected from the electricity.
2. Drain the accumulator.
3. Unscrew the side cover on the accumulator.
4. Check the pressure with the vehicle tire pump. The norm is about 1.5 atm.
5. At lower values, raise the pressure with a pump to the required level.

Instructions for setting the pressure switch Aquario type PC-5

The adjustment of the pressure switch sensor is carried out under pressure, in the operating system. Before adjusting, the pump must be turned on to raise the pressure in the system until the relay is activated and the electric motor is turned off.

Pressure adjustment is carried out with two screws, which are located under the cover of the automation. To change the relay operation limits, you need:

1. Record the on and off pressure with the pump running (take the pressure gauge reading).
2. Disconnect the pump from the power supply.
3. Remove the relay cover (after unscrewing the screws) and loosen the clamping nut of the small spring.
4. Adjust the minimum pressure by tightening or releasing the large spring marked P by turning the screw in the correct direction along the “+” (increase) signs clockwise and “-” (decrease) counterclockwise.
5. Open the valve, reducing the pressure in the system and controlling the activation of the pump.
6. Remember the pressure gauge readings, turn off the power and adjust further, approaching the optimal value.
7. To adjust the cut-off pressure, you need to tighten or release the small spring marked "ΔP" and signs "+" and "-", which shows the difference between the cut-in and cut-off pressure and is usually 1-1.5 bar.
8. Turn on the pump and wait for the relay to work. If the result is not achieved, drain the water and adjust further.

As the switch-off pressure increases, ΔP increases. In the factory version, P on = 1.6 bar, P off = 2.6 bar with Δ = 1 bar. When changing settings, for example Poff to 4 bar, the difference (differential) can be made to 1.5 bar by setting P off to 2.5 bar.

With an increase in the differential, the pressure drop in the system is higher and the pump turns on less often. But this is not comfortable for cranes.

When adjusting, the capabilities of the pump must be taken into account. If with all the losses in the passport there is 3.5 bar, then it is necessary to adjust to 3 bar, otherwise overload is inevitable, and the motor will work without shutdown.

When adjusting, the capabilities of the pump must be taken into account. If with all the losses in the passport there is 3.5 bar, then it is necessary to adjust to 3 bar, otherwise overload is inevitable, and the motor will work without shutdown.

The choice of relay must be taken seriously. Examine which environment it is intended for, the range of settings, additional functions... Relay cost is influenced by additional features pressure range and manufacturer.

Main characteristics of quality pressure switch Aquario type PC-5 manufacturer

• Available installation.
• Easy to adjust.
• Pressure switch waterproofing.
• Matching the contact group of the motor power
• Reliability and durability.

One of the management solutions autonomous water supply- connect to the pump a pressure switch RDM 5, adjustment, the instructions of which are not always clear to the user. In the same time given type devices from the Jileks brand are considered quite reliable and affordable. The setup problem can be solved, if desired, if you spend a little time studying the operation of the device.

What functions does the device perform?

In private houses, where the water supply is not connected, the issue of providing drinking quality water is solved in 2 ways:

• installation of a container or device of a pool filled with imported water;
• drilling a well to an aquifer.

Water is supplied to the house using a pump required power... But the amount of water pressure during its operation is too great to connect pumping unit to internal water supply networks directly. Therefore, an intermediate tank with a membrane is installed in the house - a hydraulic accumulator, and required pressure in the network supports the pressure switch RDM 5. The device allows you to automate the process of supplying water to autonomous systems ah water supply.

Operating principle

The device consists of a brass body with fittings for connection to the water supply network, spring valves and an electrical relay. Outside, the elements are closed with a plastic cover. The scheme of operation of the pressure switch RDM 5 is as follows:

1. The manufacturer sets the device for the lowest pressure limit of 1.4 bar, the highest - 2.8 bar. When the pressure in the accumulator is less than the lower limit, the relay contacts are closed, and the pump pumps water into the intermediate membrane tank.
2. When the pressure rises to the upper limit (2.8 bar), the spring-loaded valve is activated and opens the relay contacts. The water supply stops.
3. When a water drawdown appears in the house, the accumulator begins to empty, the pressure decreases, and when the lower threshold of 1.4 bar is reached, the relay contacts close again and the pump resumes its work.

As a rule, the RDM 5 device is completed with ready-made pumping stations, consisting of a pump, a water reservoir and a control relay itself. The station is set up at the factory and is completely ready for operation; all that remains is to connect it to the pipe and the mains. But finished goods are not suitable for everyone for the following reasons:

• the accumulator capacity is insufficient;
• the head of the standard pump is small to ensure the water supply to the required height;
• used by submersible pump lowered into the well.

In these cases, the automatic water supply system will have to be assembled from individual elements, and adjust the pressure switch accordingly, coordinating its operation with the storage tank. Before purchasing and connecting a device, it is recommended to study its technical characteristics:

• pressure regulation range in the water supply system - from 1 to 4.6 bar;
• ambient temperature range - from 0 to +40 ° С;
• minimum pressure drop - 1 bar;
• supply voltage - 220 V;
• diameter of fittings - DN 15, connection - G ’’.

If any of technical characteristics the RDM 5 relay does not suit you, you will have to look for another regulator. But practice shows that the parameters of this device meet the requirements of the overwhelming number of autonomous water supply systems.

How to adjust the device?

The pressure switch is set up after the installation of the internal and external water supply network of the house and connection to the electrical network.

Connections for outdoor and internal pipelines must be verified by tests so that subsequent leaks do not interfere with the adjustment process. Due to the leakage of the joints, the pressure before or after the pump will spontaneously decrease, which will also affect the operation of the relay.

Before adjusting, you should determine the required head value. In order to supply water to all points of water intake located on different floors, it is necessary to provide the necessary pressure in the accumulator. The efforts of the tank membrane should be sufficient to push the entire volume of water to the required height and overcome all local resistance... At home, this pressure value is most often determined experimentally.

The calculation is simple: 1 m of the lifting height is equal to 10 m of the horizontal section and corresponds to a pressure of 0.1 bar. The farthest branch of the water supply is taken into account. Having approximately determined the required pressure, it is necessary to create such a pressure from the side of the air chamber of the accumulator. To do this, remove the plastic cap from the spool (usually located at the end of the tank) and pump the air chamber with a conventional automobile pump, controlling the pressure with a pressure gauge.

1. Without connecting the branch pipe of the internal water supply network, check how the relay works in conjunction with the pump at the factory settings. At the same time, check the tightness of the external pipeline.
2. Remove the plastic relay cover covering the adjusting screws.
3. The large screw adjusts the upper limit (pump shutdown), the small screw adjusts the differential pressure. Adjust the lower limit so that it is 0.2 bar more than you pumped into the accumulator.
4. To reach the exact values, you will have to adjust several times, opening the faucet taps and draining the water from the accumulator. At the same time, record the pressure gauge readings when the pump is turned off and on and correct them with the adjusting screws.

As a result of the settings, the difference between the lower and upper limit should not be less than 1 bar. Practice shows that the optimal pressure drop is about 1.5 bar, then the pump will not turn on too often. At the end of the adjustment, do not rush to put the cover back in place, follow the system for 1 day. Minor adjustments may be needed.