INSTRUCTIONS AND PROPHECIES OF THE Blessed MOTHER ALIPIA GOLOSEEVSKY, Kyiv...
The water pressure switch is a water supply system automation device that provides automatic switch on and turn off the pump or pumping station when the water pressure changes. The relay has upper and lower thresholds. When the water pressure drops to the lower threshold, the pressure switch closes its contacts and energizes the pump. When the pressure reaches the upper threshold, the relay opens the contacts and de-energizes the pump.
Water pressure switch device
The sensitive element of the pressure switch is a flexible membrane, which bends under the action of water pressure in the pipeline, which leads to switching contacts. The resistance to water pressure is provided by a minimum pressure spring: its effect is regulated using a nut - the more the nut is tightened, the more the spring is compressed, and the more pressure is needed to trigger the relay. Another spring, the pressure differential spring, is responsible for the difference between the upper and lower pressure thresholds. In the same way, the degree of its compression is regulated by a nut, the more the spring is compressed, the greater the difference between the power-on and power-off thresholds. These nuts are used to.
Pressure switch device
Two pairs of contacts are used to connect the relay to the mains and to the pump. The pressure switch is connected to the plumbing system using a threaded hole, usually ¼ inch in diameter.
The principle of operation of the relay
When the pressure drops below the minimum threshold, the pressure switch closes the circuit and supplies power to the pumping station. The pressure in the system begins to rise, and when it reaches the maximum, the relay turns off the power.
What is a hydraulic accumulator for? This is a device that is used in water supply systems to store a certain amount of water under pressure and, when the pump is turned off, provides water pressure and the ability to consume water for a while.
First, let's look at why you need to install a water pressure switch for a borehole pump. In another way, such a relay is also called a water pressure sensor in the water supply system. The pressure switch is a small device that measures the water pressure in the system and, depending on the values obtained, turns the pump on or off.
Pressure switch ACR RM/5 represents simple design consisting of: a base, two adjusting springs, below we will consider what they are for and how to adjust, a group of contacts and a protective cover.
The principle of operation of the pressure switch for is as follows, we set the required pressure on and off. When the water pressure in the system decreases to the pressure set on the relay, at that moment the relay contacts close and the pump starts up, thereby pumping water into the accumulator, the pressure in the system rises to the level set on the relay, at which the relay opens the contacts and de-energizes our pump.
How to connect a pressure switch to a water supply system
The connection of the deep pump to the pressure switch is carried out anywhere in the water supply system, but as a rule, all automation is mounted next to the accumulator so as not to pull long wires.
To connect the pressure switch, a special tee is used, which has three fittings: for water supply, a fitting for the pressure switch and a third for water drainage.
Relay connection diagram
The electrical circuit for connecting the pressure switch was discussed earlier in the article on the dry-running switch, so go to to study it in detail.
How to set up a pressure switch for a pump
Now let's talk about how to adjust the pressure switch. Consider the example of a Chinese relay ACR PM/5. As mentioned above, the relay has two adjusting springs. A large spring is designed to adjust the shutdown pressure of the pump, i.e., the more it compresses the spring, thereby increasing the shutdown pressure, see an example in the figure
And vice versa, by decompressing the spring, we reduce the pressure at which the relay contacts open.
A small spring is designed to adjust the pressure range at which the pump will turn on and off, i.e. when the spring is compressed or released, we reduce the difference between the cut-off pressure and the cut-in pressure.
For example, we had a pump cut-off pressure of 3 bar, a turn-on pressure of 1 bar, when the spring is compressed, we reduce the pressure difference, thereby increasing the pump turn-on pressure to 2 bar.
With such simple manipulations, with adjusting springs, the pressure switch is adjusted and we achieve the pressure values \u200b\u200bthat we need, at which our pump is turned off or turned on.
Types of pressure switches, advantages and disadvantages.
On the Russian market There are two types of relays:
- mechanical
- electronic
Mechanical pressure switches wateris the simplest automation device. Its main advantage is its cheapness, the cost ranges from 300 to 3500 rubles, plus it is very easy to install.
Unfortunately, it has a number of disadvantages:
- there is no overload protection - i.e. if we have a water blockage between the pump and the pressure switch, for example, freezing in the pipe, then the pump will work until it burns out;
- absence soft start- the pump starts immediately at full power, thereby reducing the time between failures of the pump;
- cannot be used without a hydraulic accumulator - if the system is faulty or missing, and due to the fact that the pump starts at full power, the pipes in the water supply system tremble and this can lead to a rupture of the system with all the sad consequences of flooding the room.
Electronic water pressure switchfor the pump, in comparison with the mechanical one, it has finer settings for the water pressure in the system. As a rule, a flow sensor is also built into such a relay, which protects the pump from “dry running” and thereby eliminates the installation.
Electronic water pressure switch for pump
Pressure switch overview
The cheapest relay on the Russian market is a Chinese-made relayACR PM/5. Has no protection against dust and water, has two groups of contacts.
The German relay, under the brand name Condor MDR5 / 8, has proven itself very well. It has a dust and moisture-proof housing, gold-plated contacts, the contact group is bipolar, i.e. open and phase, and zero. Very easy adjustment, no effort required. It has two groups of contacts: normally closed and normally open, therefore it can be used both as a pressure relay and as a dry-running protection relay. There is a hole on the body for installing a pressure gauge.
Another high-quality relay Tival FF4-8 (Grundfos), made in Germany, has an index of protection against external environment IP52. It has a high-quality case and a dense cable outlet. The positive aspect of this relay is the pressure adjustment without a pressure gauge, inside the relay there is a calibrated pressure scale and a pressure delta scale.
The disadvantages include a single-pole contact group, it opens only the phase.
Another representative of a quality relay is the Danfoss KPI relay, made in Denmark. It has gold-plated contacts, which eliminates the burning of contacts. Like the previous relay, it can be adjusted without a pressure gauge on a scale. Can serve as a dry run relay.
Of the minuses - single-pole.
The pressure switch is a small but indispensable unit of a large and small pumping station. And if all its other elements just need to be connected correctly, then it will also have to be additionally configured. It is this device that is responsible for automating the pumping process. It turns on and off the equipment according to the pressure in the hydraulic tank.
Properly performed adjustment of the pressure switch for the pump is a guarantee of comfort and long service life equipment. About how it is performed, what actions need to be taken and what data to know for fine-tuning, we detail in the article. You will find out why and in what situations it is produced.
Except step by step description we provide adjustment procedures valuable advice reported by hydraulic engineers. To optimize perception, the text is supplemented with photo collections, diagrams, video guides.
Numerous varieties, which are equipped with almost all pumping stations, are arranged in approximately the same way.
Inside the plastic case there is a metal base on which the rest of the elements are fixed:
- membrane;
- piston;
- metal platform;
- electrical contact assembly.
On top, under the plastic cover, there are two springs - large and small. When the diaphragm is under pressure, it pushes the piston.
He, in turn, raises the platform, which acts on a large spring, compressing it. A large spring resists this pressure, limiting the movement of the piston.
The small distance that separates the large and small adjusting springs is enough to regulate the operation of a whole range of devices. The platform under pressure from the membrane gradually rises until its edge reaches the small spring. The pressure on the platform at this moment increases, as a result, its position changes.
Image gallery
This causes the contacts to switch, which changes the mode of operation of the pump, and it turns off. To switch contacts there is a special hinge with a spring.
When the platform overcomes the level at which this hinge is located, the electrical contacts change position, breaking the power supply circuit. At this point, the pump is switched off. After that, the water stops flowing and the pressure exerted on the membrane decreases as the water is consumed from the accumulator.
Accordingly, the platform smoothly lowers. When its position is lower than the spring hinge of the electrical contacts, they rise, turning the power back on.
The pressure switch is a small device that allows you to turn the pump on and off depending on the presence or absence of water in the accumulator
The pump pumps water into the hydraulic tank, the relay membrane presses on the platform, it rises, reaches a large spring, etc. The cycle resumes and is performed automatically.
With the help of a large spring, the pressure indicator is set at which the pump unit must be turned on, and the small one determines not the “ceiling” of the allowable pressure in the system, as you might think, but the difference between these two indicators. it important point, which is useful when learning the procedure for doing your own pump.
Is there a need for a setting at all?
Of course, on your own or with the help of a specialist, but everyone who has assembled their pumping station from individual elements will need to set up the pressure switch.
There is an opinion that ready-made pumping stations purchased assembled are equipped with a pressure switch already configured and prepared for operation. In practice, this is not always the case.
Before connecting and adjusting the pressure switch, carefully study technical documentation provided by the manufacturer to find out the pressure limits
Each plumbing system has individual characteristics. And the needs of the residents of the house may be different.
How to set the relay correctly?
There is a cover on the pressure switch housing, and under it there are two springs equipped with nuts: large and small. By rotating these springs, the lower pressure in the accumulator is set, as well as the difference between the cut-in and cut-out pressures. The lower pressure is regulated by a large spring, and a small one is responsible for the difference between the upper and lower pressure.
There are two adjusting springs under the cover of the pressure switch. The large spring regulates the activation of the pump, and the small spring regulates the difference between the activation and deactivation pressures.
Before starting the setup, it is necessary to study the technical documentation of the pressure switch, as well as the pumping station: the hydraulic tank and its other elements.
The documentation indicates the operating and limiting indicators for which this equipment is designed. During the adjustment, these indicators should be taken into account so as not to exceed them, otherwise these devices may soon break down.
Sometimes it happens that during the adjustment of the pressure switch, the pressure in the system still reaches the limit values. If this happens, you just need to turn off the pump manually and continue tuning. Fortunately, such situations are extremely rare, since the power of domestic surface pumps there just isn't enough to push a hydraulic tank or system to its limits.
On the metal platform where the adjusting springs are located, the signs “+” and “-“ are made, which allow you to understand how to rotate the spring in order to increase or decrease the indicator
It is useless to adjust the relay if the accumulator is filled with water. In this case, not only the water pressure will be taken into account, but also the parameters of the air pressure in the tank.
To adjust the pressure switch, follow these steps:
- Set the operating air pressure in the empty accumulator.
- Turn on the pump.
- Fill the tank with water until the lower pressure is reached.
- Switch off the pump.
- Turn the small nut until the pump starts.
- Wait until the tank is full and the pump is turned off.
- Open water.
- Rotate the large spring to set the cut-in pressure.
- Turn on the pump.
- Fill the hydraulic tank with water.
- Correct the position of the small adjusting spring.
You can determine the direction of rotation of the adjusting springs by the signs “+” and “-”, which are usually located nearby. To increase the switching pressure, the large spring must be rotated clockwise, and to decrease this figure, it must be rotated counterclockwise.
The adjusting springs of the pressure switch are very sensitive, so they must be tightened very carefully, constantly checking the condition of the system and the readings of the pressure gauge
The rotation of the adjusting springs when adjusting the pressure switch for the pump must be done very smoothly, about a quarter or half a turn, these are very sensitive elements. Pressure gauge at re-enabling should show low pressure.
With regard to indicators when adjusting the relay, it will be useful to remember the following points:
- If the hydraulic tank is filled, and the pressure gauge remains unchanged, it means that the maximum pressure in the tank has been reached, the pump should be turned off immediately.
- If the difference between the cut-off and turn-on pressures is about 1-2 atm, this is considered normal.
- If the difference is greater or less, the adjustment should be repeated, taking into account possible errors.
- The optimal difference between the set lower pressure and the pressure determined at the very beginning in an empty accumulator is 0.1-0.3 atm.
- In the accumulator, the air pressure should not be less than 0.8 atm.
The system can turn on and off properly in automatic mode and with other indicators. But these boundaries make it possible to minimize the wear of equipment, for example, the rubber lining of a hydraulic tank, and extend the operation time of all devices.
For normal operation, it is recommended to measure the air pressure in the accumulator every three months. This measure will help maintain stable settings in the operation of the equipment. A sharp change in indicators may indicate some kind of breakdown that needs to be fixed.
In order to quickly monitor the status of the system, it makes sense to simply record the readings of the water pressure gauge from time to time when turning the pump on and off. If they correspond to the numbers set when setting up the equipment, the system can be considered normal.
A noticeable difference indicates that it is necessary to check the air pressure in the hydraulic tank and, possibly, reconfigure the pressure switch. Sometimes you just need to pump some air into the accumulator, and the performance will return to normal.
The accuracy of the pressure gauge has a certain error. This may be partly due to the friction of its moving parts during measurements. To improve the process of readings, it is recommended to additionally lubricate the pressure gauge before starting measurements.
The pressure switch, like other mechanisms, tends to wear out over time. Initially, you should choose a durable product. An important factor in the long-term operation of the pressure switch is correct settings. do not use this instrument at the maximum allowable upper pressures.
If there are problems and inaccuracies in the operation of the pressure switch, it may need to be disassembled and cleaned of contaminants
A small margin should be left, then the elements of the device will not wear out so quickly. If it is necessary to set the upper pressure in the system to sufficient high level, for example, in five atmospheres, it is better to purchase a relay with a maximum allowable value of work in six atmospheres. Finding such a model is more difficult, but it is quite possible.
Serious damage to the pressure switch can be caused by contamination in. This is a typical situation for old water pipes made of metal structures.
Before installing the pumping station, it is recommended to thoroughly clean the water supply. Doesn't hurt and complete replacement metal pipes on plastic structures, if possible.
When adjusting the relay, the adjusting springs should be treated with extreme care. If they are compressed too much, i.e. twisted during the setup process, errors will very soon begin to be observed during operation of the device. Relay failure in the near future is almost guaranteed.
If during the check of the operation of the pumping station a gradual increase in the shutdown pressure is observed, this may indicate that the device is clogged. You don't need to change it right away.
It is necessary to unscrew the four mounting bolts on the pressure switch housing, remove the membrane assembly and thoroughly flush the inside of the switch, where possible, as well as all small openings.
Sometimes it is enough just to remove the relay and clean its holes from the outside without disassembly. It also does not hurt to clean the entire pumping station. If water suddenly begins to flow directly from the relay housing, it means that particles of pollution have broken through the membrane. In this case, the device will have to be completely replaced.
Conclusions and useful video on the topic
An overview of the pressure switch device is presented here:
This video details the process of setting up the pressure switch:
Setting up a pressure switch is not always easy. We need to act carefully and carefully. But understanding the principles of operation of the device and the features of its settings allows you to cope with this task quite satisfactorily.
We are waiting for your stories about the experience of installing and configuring pressure switches, operation pumping system equipped with the device. Do you have any questions while reading the material? Ask them and comment on the article in the block below.
Operation of pumping equipment in the system autonomous water supply regulated by special automation. One of the main parts that control network parameters is a pressure switch. This device is factory set to a low and high limit at which the pump will turn on. If it is necessary to change the indicators, the pressure switch of the pumping station is adjusted. Such an operation does not require the involvement of specialists, knowing the settings rules, it can be carried out independently.
Water supply network with relay
How the pressure switch works
Regardless of the manufacturer, the water pressure switch in the water supply system is a compact unit with two springs and electrical contacts. The hydraulic part of the device is a membrane with a piston and two springs. different sizes. The electrical part is a contact group, opening / closing network for turning the pump on / off. All structural parts, including the terminal block, are attached to the metal base. The device has several terminal groups:
- for connecting voltage 220V;
- for grounding;
- terminals for the pump.
On the back side there is a nut for connecting to the fitting. From above, the device is covered with a plastic cover, fixed to the screw of a larger spring. Products from different factories can be equipped additional elements, have a characteristic shape and arrangement of nodes, but they all have a similar design. The sensor can be mechanical or electronic. Mechanical devices are more popular due to their low cost.
Relay design
Attention. To remove from the device plastic cover screwdriver or wrench required.
The principle of operation of the relay
The pressure switch device of the pumping station does not require human intervention in the process of turning the pump on and off. The principle of its operation is based on changing the degree of impact on the piston responsible for closing the contacts. A large spring mounted on a stem with an adjustment nut counteracts the movement of the diaphragm and piston. When the pressure in the system decreases due to water parsing, the contact platform lowers and closes the contacts. The pump turns on and begins to pump fluid.
Mechanical pressure controller
The flow of water into the accumulator leads to an increase in air pressure on the membrane of the device. The piston, overcoming the action of the spring, begins to displace the contact platform. This process causes the electrical contacts to open. The current is turned off not immediately, but when the platform is retracted to a distance determined by the setting of the small spring. This regulator is responsible for the pressure difference. After the contacts are completely open, the unit stops pumping water.
Information. A large spring is used to adjust the lower pressure level (on), a small spring is used to set the upper limit (off).
Preparation of the pumping station
When organizing individual water supply, special equipment is installed - a pumping station. It consists of two parts:
- submersible (surface) pump;
- hydraulic accumulator.
A sealed tank with a rubber membrane installed inside serves to store a supply of water and maintain a stable pressure in the system. Before you start setting up the pressure switch of the pumping station with your own hands, you should prepare the tank. The tank consists of a rubber pear into which water is pumped, and a chamber filled with air. The magnitude of the air pressure affects the operation of the entire water supply system, so it is necessary to set up a pumping station.
Training membrane tank begins with the complete draining of water from the pipeline and the tank itself. For this, the bottom tap of the system is used. Air is injected into an empty tank, its pressure must be less than the lower limit by 10%. The minimum pressure value is determined depending on the size of the accumulator:
- 20-30 l - 1.4-1.7 bar;
- 50-100 l - 1.8-1.9 bar.
After determining the pressure in the storage tank, the system is immediately filled with water; the rubber bulb must not be allowed to dry out.
Pumping station with hydraulic accumulator and sensor
Attention. Self-checking the pressure in the tank is necessary when assembling equipment from individual parts. Modern models factory-made pumping stations have ready-made settings specified in the documents.
In order for the tank membrane to serve for a long time, it is recommended to set the pressure in the accumulator to 0.1-0.2 atm. lower than the minimum level in the system.
Where to install a mechanical controller?
When choosing a place to connect the pressure switch to a submersible pump, possible turbulence and pressure surges should be avoided. The best option- installation near the accumulator. The operating conditions of the device should be taken into account; in the documents, the manufacturer indicates the permissible parameters of temperature and humidity. With a moisture-proof version of the sensor, you can install it together with the storage in the caisson. In order for the controller to start functioning, it must be connected to the electrical and water supply network.
For the relay, it is desirable to allocate a separate electric line, but this condition is not required. A cable with a cross section of 2.5 mm 2 is laid from the shield. For safety, it is recommended to install a circuit breaker, with parameters corresponding to the characteristics of the pump. The device must be earthed.
The terminal block has three groups of contacts: ground, phase and zero from the shield, wire from the pump. 
The connection is carried out as standard - the wire is stripped, inserted into the connector and fixed with a bolt
Attention. Connection to the electrical network is made according to the inscriptions indicated on the contact group.
A submersible pump with a pressure switch can be connected using a tee or a five-way fitting. The connection is made through the nut on the back of the device. In the first case, the device is installed directly on the highway. The second option is preferable when a five-part assembly is assembled:
- Submersible or surface pump.
- Pressure gauge.
- Hydraulic accumulator.
- Pressure meter.
- Pipeline.
Relay installation diagram
Advice. All threaded connections of the assembly need to be sealed; sealant or FUM tape is used for this purpose.
Mandatory elements of the water supply network at home are filters. These devices are necessary to purify the liquid from impurities that impair the operation of equipment, including pressure switches. After connecting the sensor to the water supply and the electrical network, all that remains is to adjust the pumping station with your own hands.
The filter can be installed before the accumulator and automation. It will trap all large particles that can damage relay systems, membranes and rubber gaskets. But in this case, it is necessary to clean it regularly - severe pollution worsens it. throughput. This increases the load on the pump, which can lead to premature failure. When installing a filter after the station, it will operate normally without increasing the load. By weakening the pressure, the consumer will understand that the filter element requires cleaning.
Relay setting
The manufacturer provides the setting of pumping stations for average indicators:
- lower level - 1.5-1.8 bar;
- upper level - 2.4-3 bar.
Lower pressure threshold
If the consumer is not satisfied with such values, then knowing how to adjust the pressure in the pumping station, they can be changed. Having dealt with the installation of the correct pressure in the storage tank, proceed to adjust the sensor settings:
- The pump and relay are de-energized. All liquid is drained from the system. The pressure gauge is at zero at this point.
- The plastic cover of the sensor is removed with a screwdriver.
- Turn on the pump and record the pressure gauge readings at the time the equipment is turned off. This indicator is the upper pressure of the system.
- The tap farthest from the unit opens. The water gradually drains, the pump turns on again. At this point, the lower pressure is determined by the pressure gauge. The pressure difference, which this moment the equipment is set up, it is calculated mathematically - subtracting the results obtained.
Attention. To obtain the correct setting, you need a reliable pressure gauge whose readings can be trusted.
Having the opportunity to evaluate the pressure from the tap, select the required setting. Adjustment for increasing the pressure of the pumping station is carried out by tightening the nut on a large spring. If the pressure needs to be reduced, the nut is loosened. Do not forget that adjustment work is carried out after disconnecting the device from the power supply.
Attention. The setting is done carefully, the relay is a sensitive device. One turn of the nut changes the pressure by 0.6-0.8 atmospheres.
Upper pressure threshold
To set the optimal frequency of switching on the pump, it is necessary to adjust the pressure difference. A small spring is responsible for this parameter. The optimal value of the difference between the upper and lower pressure thresholds is 1.4 atm. If it is necessary to increase the upper limit at which the unit turns off, then the nut on the small spring is turned clockwise. When decreasing - in the opposite direction.
Tuning scheme
What effect does this adjustment have on the equipment? An indicator below the average (1.4 atm.) Will provide a uniform supply of water, but the unit will often turn on and quickly break down. Exceeding the optimal value contributes to a gentle use of the pump, but the water supply will suffer due to noticeable pressure surges. Adjustment of the pressure difference of the pumping station is carried out smoothly and carefully. The impact needs to be verified. The scheme of actions performed when setting the lower pressure level is repeated:
- All appliances are disconnected from the mains.
- Water is drained from the system.
- The pumping equipment is turned on and the result of the adjustment is evaluated. In case of unsatisfactory performance, the procedure is repeated.
When making pressure difference adjustments, there are limitations that must be taken into account:
- Relay parameters. You can not set the upper pressure threshold equal to 80% of the maximum indicator of the device. Data on the pressure for which the controller is designed is present in the documents. household models usually withstand up to 5 atm. If it is necessary to raise the pressure in the system above this level, it is worth buying a more powerful relay.
- Pump characteristics. Before choosing an adjustment, you must check the characteristics of the equipment. The unit must turn off at a pressure that is 0.2 atm. below its upper limit. In this case, it will function without overloads.
Features of adjustment "from scratch"
If both relay springs are weakened, the automation of the pumping station is adjusted according to the following algorithm:
- The unit is turned on to pump water into the system. The pressure level is controlled by observing the jet from a remote faucet. If the pressure is acceptable, then the pressure gauge reading is fixed, and the pump is turned off.
- Having disconnected the sensor from the network, open the cover and twist the nut of the large spring until the contacts close.
- The box is closed and the device is connected to the network again. The pump is turned on and left to work until the pressure on the pressure gauge reaches a mark equal to the previous value plus 1.4 atm.
- The unit and relay are disconnected from power, then tighten the nut on the smaller spring until the contacts open. The lower and upper threshold settings are now complete.
Pressure switch with pressure gauge
Using a sensor without a hydraulic accumulator
For some equipment models, a borehole pump connection diagram with a pressure switch without storage tank. A special automatic controller starts and stops the unit when the limit values are reached. The electronic unit has the function of protection against "dry running" and provides safe work systems.
Attention. The disadvantage of such a scheme is the absence of a minimum supply of water, which is provided by a membrane tank.
Electronic pressure switch for surface and submersible pump
Water pressure switch for pump Nowadays, it is widely used for water supply systems of a private house, cottage or other facilities where automatic water supply to the points of water intake is needed. Today, a water pressure switch is a necessary attribute for pumping equipment for an area where there is no centralized water supply system: personal plots, country houses, cottages, etc.
Today we will analyze the device and the principle of operation, specifications and pressure switch settings, consider the differences and their application, as well as the main malfunctions, their causes and repairs.
Application features and price
The water pressure switch is intended for use with electric water pumps with a single-phase connection of 220 Volts in the water supply system:
- pumping stations for water supply and hydraulic accumulator;
— centrifugal surface pumps;
— borehole pumps;
- submersible;
- submersible vibration pumps type "Kid" or "Brook".
Pump pressure switch
As a rule, the pressure switch is already included in the package, and sometimes submersible pumps. In other cases, this device is purchased separately. The connection to the main line is made using a five-pin fitting. The relay is available with either external thread("male"), or with a nut with internal thread ("mother"). The thread diameter is usually 1/4'.
It is worth noting that the price of a water pressure switch directly depends on the manufacturer, for example, a pressure switch made in Denmark "Grundfos" or Italy "Speroni" - from 1000-2000 rubles, and Chinese ones can be bought for 200-300 rubles. Russian "Dzhileks" RDM-5 or RD-5 - from 700 rubles. But, if you choose quality, then it is better to buy automation under a European brand.
In addition, the pressure switch may have a built-in pressure gauge, or it may be part of the pump automation unit in conjunction with a dry-running protection relay. Accordingly, this is also reflected in the price in the direction of its increase.
The device and principle of operation of the water pressure switch in the water supply system
The pressure switch consists of a plastic case, under which a membrane is “hidden”, which controls the operation of a normally closed group of contacts. This membrane is connected to the pressure line of the water supply system.
In the operation of the relay, there are such concepts as the pump on pressure and the pump off pressure. When buying a pressure switch, you must remember that this mechanism has a factory setting of the on and off parameters.
The pump turns on when the pressure threshold for turning it on in the water supply system (2.6 atm) is exceeded and turns off when the turn-off pressure drops (1.3 atm). As a rule, switching on occurs at 2.6 atm, and switching off - when the water pressure in the system drops to 1.3 atm, but these parameters can also be configured by hand.
In the photo and connection diagram, you can clearly see the pressure switch device for the pump.
Water pressure switch device: connection diagram
1 - nut for adjusting the lower pressure limit;
2 - nut for adjusting the difference between the lower and upper pressure limits;
3 - terminals for connecting wires from the pump;
4 - terminals for connection to a single-phase electrical network;
5 - terminals for grounding.
In fact, a water pressure switch for a pump is a relay of a bundle of electrical circuits that has two contacts and responds to changes in pressure parameters in the water supply system. The pump pumps water while the contacts are in electrical circuit closed, but when they open, the power to the pump is cut off and it turns off.
The operation of the contacts in the electrical circuit directly depends on the set limits for the turn-on pressure and the turn-off pressure of the pump. After a certain period of time, these contacts may oxidize, requiring cleaning.
Setting the water pressure switch for the accumulator and pump
As we noted above, the relay initially has its own factory settings already set. But we can also configure the operation of this mechanism on our own to the values that are convenient for us. How to do it?
1. In order to increase the lower pressure limit, we need to turn the nut that regulates this limit clockwise (see diagram above) or counterclockwise to decrease this limit.
2. Both of these nuts have a mechanical effect on the pressure adjustment spring in the relay. With the help of the first, we set the lower limit, and the second - we set the necessary difference in pressure limits.
Specifications of the pressure switch
Relay specifications and settings
Malfunctions of the pressure switch for the pump and their solutions
1. The pump does not turn on.
It is necessary to check the presence of water in the suction section of the pipeline and the voltage in the mains. Turn off the power, then turn it back on after a while.
2. The pump frequently turns on and off.
Try lowering the shutdown pressure threshold, it may be too high.
3. The pump does not turn off.
Check the value of the maximum operating pressure of the pump. Normally, it should be 0.8 atmospheres higher than the switch-on pressure value. It is also worth checking the line for leaks and air accumulation in the water supply system.
Today we dismantled the device and the principle of operation water pressure switch for pump, its features, technical characteristics and application in everyday life. This is a convenient, modern and inexpensive mechanism that allows you to automate the operation of the entire plumbing system of a private house. Let's watch the video.
