Relay for turning on the well pump. How to adjust the water pressure switch for the pump? How a relay works

17.06.2019

The pump pressure switch is a device that allows you to control the operation of pumping equipment in automatic mode.

How a pressure switch works

The pump pressure switch is a spring block that transmits a signal received from a membrane that receives water pressure to electrical contacts that make and break an 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 membrane deformation 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 is completely repeated.

The standard pressure switch setting is between 1.4 and 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 frequent pump activation. 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 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 water is completely drained from it and only then the pressure is measured. For measurement, you can use a car pressure gauge, with which you can check tire pressure.

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

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

Relay setting

To do this, the pumping station is reassembled and put into operation. Pressure adjustment is carried out on the working equipment. To do this, use two adjusting screws located under the cover of the automation group of the device. The cut-in and cut-out pressure levels are adjusted separately.

The sequence of actions is as follows.

The inclusion of the pump in operation is fixed. At the same time, the pressure in the water supply system is measured.
The station is disconnected from the power supply
Removing the relay cover
Adjustable (loosened or vice versa tightened) screw with the appropriate marking
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. This measures the new pressure at which the pump will start working.
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.

The principle of operation of all products in this category is identical. The algorithm is the simplest: the pressure in the system has dropped below the critical one - the relay turns on the pump; increased to the maximum set value (during setting) - breaks the circuit of its power supply with contacts.

1. Unipump

Good domestic development, characterized by high quality and reasonable cost. It is supplied to the market in various modifications.

Peculiarities

Designed to work with pumps up to 1.5 kW.
Pressure gauge built into the pressure switch housing. Therefore, it is not necessary to install the measuring device separately.
Connections - a quarter of an inch.

2. Grundfos

Reliable pressure switches from a Danish manufacturer with an impeccable reputation "GRUNDFOS".

Peculiarity

High degree of security (IP52). Such products are suitable for installation even in places with excessive humidity (damp basements, caissons, and so on).
Reliability at work.
Some modifications (for example, FF 4-4 or 4-8) are low-current devices. They cannot be connected directly to the industrial / voltage network, only through an “intermediate link” in the form special device(converter).
Impressive assortment. Relays differ mainly in the value of the upper limit of operation.

Many experts are unanimous in their opinion - most of the cost of the Grundfos pressure switch falls on the "recognition" of the brand. An analysis of the operation of such automation shows that domestic analogues are in no way inferior to the "Danes", although the price for them is much lower.

3.Condor

This is an example of German industry, which has won a lot of sympathy due to its uptime.

Peculiarities

The pressure switch is bipolar. That is, when triggered, both circuits (phase and zero) open at the same time, which makes the operation of the system safer.
Adjustment is made by rotation.
Versatility of settings.
It is possible to connect a manometer.
The cost is high.

4. Danfoss (KP1 series)

Pressure switch from a well-known Danish manufacturer. It is expensive, but the high price is justified.

Peculiarities

Gold-plated contacts. Therefore, "sticking" is excluded.
The presence of a tuning scale allows you to do without an indicating device (pressure gauge).

This Chinese product is often confused with a dry-running relay, although its purpose in the circuit is completely different. The only plus is the low cost.

But such "cheapness" has also reverse side. Here are just the main shortcomings that are noted by users on thematic forums.

Contacts are not silver plated (normal). Therefore, due to their burning, the circuit may not open at the right time.
Moisture and dust resistance - zero.
They do not work out the guaranteed service life - they break quite quickly.

6.ITALTECNICA

Relay made in Italy. Together with pumps modification PM/5 is used. Attracts not a high price with excellent quality and reliability. It is mounted in the control circuits of the cold water circuit. Pressure control limits ( bar) – from 1 to 5 (lower/upper). The warranty is small - only a year.

If not a pump, but a station is installed in the water supply system, then it is equipped with a modification G. Its main difference is within the setting - from 1.4 to 2.8.

Contact group - copper lamellas.
Non-stick coating– Ag-Ni layer.
Plastic housing with insulating gasket.

One of essential elements control of the water pumping station is a pressure switch. It provides automatic switch on and turning off the pump, controlling the water supply to the tank according to the specified parameters. There are no clear recommendations on what the values of the lower and upper pressure limits should be. Each consumer decides this individually within allowable norms and instructions.

The device and principle of operation of the water pressure switch

Structurally, the relay is made in the form of a compact unit with maximum and minimum pressure springs, the tension of which is regulated by nuts. The membrane connected to the springs reacts to changes in the pressure force. Upon reaching the minimum value, the spring weakens, at the maximum level, it is compressed more strongly. The force exerted on the springs causes the opening (closing) of the relay contacts, turning the pump off or on.

The presence of a relay in the water supply system allows you to provide a constant pressure in the system and the necessary water pressure. The pump is controlled automatically. Properly set, they ensure its periodic shutdown, which contributes to a significant increase in the period of trouble-free service.

The sequence of operation of the pumping station under the control of the relay is as follows:

The pump pumps water into the tank.
The water pressure is constantly increasing, which can be tracked on the pressure gauge.
When the set upper pressure limit is reached, the relay is activated and turns off the pump.
As the water pumped into the tank is used up, the pressure decreases. When it reaches the lower level, the pump will turn on again and the cycle will repeat.

Device diagram and components of a typical pressure switch

The main parameters of the relay operation:

Lower pressure (switch-on level). The relay contacts that turn on the pump are closed, and water enters the tank.
Upper pressure (off level). The relay contacts open, the pump turns off.
Pressure range - the difference between the two previous indicators.
The value of the maximum allowable shutdown pressure.

Setting the pressure switch

During the assembly process of the pumping station, special attention is paid to setting the pressure switch. The ease of use, as well as the terms of the trouble-free service of all components of the device, depend on how correctly its limiting levels are set.

At the first stage, you need to check the pressure that was created in the tank during the manufacture of the pumping station. Usually, at the factory, the on-off level is set to 1.5 atmospheres, and the off level is 2.5 atmospheres. This is checked with an empty tank and the pumping station disconnected from the mains. It is recommended to check with an automotive mechanical pressure gauge. It is placed in a metal case, so the measurements are more accurate than using electronic or plastic pressure gauges. Their readings can be affected by both the air temperature in the room and the level of battery charge. It is desirable that the scale limit of the pressure gauge be as small as possible. Because on a scale of, for example, 50 atmospheres, it will be very difficult to accurately measure one atmosphere.

To check the pressure in the tank, you need to unscrew the cap that closes the spool, connect a pressure gauge and take a reading on its scale. The air pressure should continue to be checked periodically, for example once a month. In this case, water must be completely removed from the tank by turning off the pump and opening all taps.

Another option is also possible - carefully monitor the shutdown pressure of the pump. If it has increased, this will mean a decrease in air pressure in the tank. The lower the air pressure, the more water can be created. However, the pressure spread from a completely filled to a practically empty tank is large, and all this will depend on the preferences of the consumer.

Having chosen the desired mode of operation, you need to set it by bleeding excess air for this, or pump it up additionally. It must be borne in mind that one should not reduce the pressure to a value of less than one atmosphere, and also pump it too much. Due to the small amount of air, the rubber container filled with water inside the tank will touch its walls and be wiped. And excess air will not make it possible to pump in a lot of water, since a significant part of the tank volume will be occupied by air.

Setting the pump on and off pressure levels

Which are supplied assembled, the pressure switch is pre-configured for the best option. But when it is installed from various elements at the place of operation, the relay must be configured. This is due to the need to ensure an effective relationship between the relay settings and the volume of the tank and the pump head. In addition, it may be necessary to change the initial setting of the pressure switch. The procedure for this should be as follows:

In practice, the power of the pumps is chosen such that it does not allow pumping the tank to the extreme limit. Typically, the cut-off pressure is set a couple of atmospheres above the turn-on threshold.

It is also possible to set pressure limits that differ from the recommended values. In this way, you can set your own version of the operating mode of the pumping station. Moreover, when setting the pressure difference with a small nut, one must proceed from the fact that the starting point of reference should be the lower level set by the large nut. You can set the upper level only within the limits for which the system is designed. In addition, rubber hoses and other plumbing also withstand pressure, not higher than the calculated one. All this must be taken into account when installing the pumping station. In addition, the excessive pressure of water from the tap is often completely unnecessary and uncomfortable.

Pressure switch adjustment

Adjustment of the pressure switch is practiced in cases where it is necessary to set the levels of upper and lower pressures to the specified values. For example, you want to set the upper pressure to 3 atmospheres, the lower - 1.7 atmospheres. The adjustment process is as follows:

Turn on the pump and pump water into the tank to the pressure on the pressure gauge of 3 atmospheres.
Switch off the pump.
Open the relay cover and slowly turn the small nut until the relay operates. Turning the nut clockwise means an increase in pressure, in the opposite direction - a decrease. The upper level is set - 3 atmospheres.
Open the tap and drain the water from the tank to the pressure value on the pressure gauge of 1.7 atmospheres.
Close the tap.
Open the relay cover and slowly turn the large nut until the contacts actuate. The lower level is set - 1.7 atmospheres. It should be slightly higher than the air pressure in the tank.

If high pressure is set to turn off and low to turn on, the tank fills with more water and it is not necessary to turn on the pump frequently. The inconvenience arises only because of the large pressure difference when the tank is full or almost empty. In other cases, when the pressure range is small, and the pump often has to be pumped up, the water pressure in the system is uniform and quite comfortable.

In the next article, you will learn the most common connection schemes.

The operation of pumping equipment in the autonomous water supply system is 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 of 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 of various factories can be equipped with 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.

The preparation of the 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 pumping stations, manufactured in the factory, 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?

Choosing a place to connect the pressure switch to submersible pump, possible turbulence and head surges must be avoided. The best option is to install 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 electrical 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. Everything threaded connections nodes need sealing, for this purpose a sealant or FUM tape is used.

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 impairs its 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 to which the equipment is currently set 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.
Turns on pump equipment and the tuning result 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, the wiring diagram is used well pump with 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

For a stable supply of water with the required pressure values, it is not enough just to buy a pumping station. The equipment still needs to be set up, launched and properly operated. Admit it, not all of us are familiar with the intricacies of customization. And the prospect of spoiling devices with incorrect actions is not very attractive, do you agree?

You will learn about the causes of pressure drops and learn how to eliminate them. Graphic and photo applications will explain how to properly configure pumping equipment.

A ready-made pumping station equipped with the manufacturer is a mechanism for forced water supply. The way it works is extremely simple.

The pump pumps water into an elastic container located inside a hydraulic accumulator, also called a hydraulic tank. When filled with water, it expands and presses on that part of the tank that is filled with air or gas. The pressure, reaching a certain level, causes the pump to turn off.

During the intake of water, the pressure in the system drops, and at a certain moment, when the values \u200b\u200bset by the owner are reached, the pump starts working again. The relay is responsible for turning the device off and on, the pressure level is controlled using a pressure gauge.

Violations in the operation of a household pumping station can cause breakdowns of plumbing equipment

The article we recommend will acquaint you with the principle of operation, varieties and proven installation schemes in more detail.

Causes of hardware problems

The statistics of malfunctions in the operation of domestic pumping stations says that most often problems arise due to a violation of the integrity of the membrane, pipeline, water or air leakage, and also due to various contaminants in the system.

The need to intervene in its work may arise due to many reasons:

sand and various substances dissolved in water can be corrosive, lead to malfunctions and reduce equipment performance. To prevent clogging of the device, it is necessary to use filters that purify the water.
The decrease in air pressure in the station causes frequent operation of the pump and its premature wear. It is recommended to measure the air pressure from time to time and adjust it if necessary.
The lack of tightness of the joints of the suction pipeline is the reason that the engine runs without turning off, but cannot pump liquid.
Improper adjustment of the pressure of the pumping station can also cause inconvenience and even breakdowns in the system.

To extend the life of the station, it is recommended to periodically audit. Any adjustment work must begin with disconnecting from the mains and draining the water.

Energy consumption and maximum head should be checked periodically. An increase in energy consumption indicates friction in the pump. If the pressure drops without leaks detected in the system, then the equipment is worn out

Correction of errors in work

Before embarking on a more serious intervention in the operation of the equipment, it is necessary to take the simplest measures - clean the filters, eliminate leaks. If they do not produce results, then proceed to further steps, trying to identify the root cause.

The next thing to do is to adjust the pressure in the accumulator tank and.

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The following are the most common malfunctions in the domestic pumping station, which the user can try to solve on his own. For more serious problems, contact the service center.

Violation of the rules of operation

If the station runs continuously without shutting down, the likely cause is incorrect relay adjustment - a high shutdown pressure is set. It also happens that the engine is running, but the station does not pump water.

The reason may lie in the following:

When first started, the pump was not filled with water. It is necessary to correct the situation by pouring water through a special funnel.
The integrity of the pipeline is broken or formed airlock in the pipe or in the suction valve. To find a specific cause, it is necessary to make sure that: the foot valve and all connections are tight, there are no bends, narrowings, hydraulic locks along the entire length of the suction pipe. All malfunctions are eliminated, if necessary, replace damaged areas.
The equipment works without access to water (dry). It is necessary to check why it is not there or to identify and eliminate other causes.
The pipeline is clogged - it is necessary to clean the system of contaminants.

It happens that the station very often works and turns off. Most likely this is due to a damaged membrane (then it is necessary to replace it), or the system is missing. In the latter case, it is necessary to measure the presence of air, check the tank for cracks and damage.

Before each start, it is necessary to pour water into the pumping station through a special funnel. She must not work without water. If there is a possibility of the pump running without water, you should purchase automatic pumps equipped with a flow controller

Less likely, but it can happen that it is open and blocked due to debris or a foreign object. In such a situation, it will be necessary to disassemble the pipeline in the area of \u200b\u200bpossible blockage and eliminate the problem.

Engine malfunctions

The household station engine does not run and does not make noise, possibly for the following reasons:

The equipment is disconnected from the power supply or there is no mains voltage. You need to check the wiring diagram.
The fuse has blown. In this case, you need to replace the element.
If you cannot turn the fan impeller, then it is jammed. You need to find out why.
Relay damaged. You need to try to adjust it or, if it fails, replace it with a new one.

Engine malfunctions most often force the user to use the services of a service center.

Problems with water pressure in the system

Insufficient water pressure in the system can be explained by several reasons:

The pressure of water or air in the system is set to an unacceptably low value. Then you need to configure the relay operation in accordance with the recommended parameters.
Piping or pump impeller blocked. Cleaning the elements of the pumping station from contamination may help solve the problem.
Air enters the pipeline. Checking the elements of the pipeline and their connections for tightness will be able to confirm or refute this version.

Poor water supply can also be caused by air being drawn in due to loose connections. water pipes or the water level has dropped so much that when it is taken, air is pumped into the system.

Poor water pressure can create significant discomfort when using the plumbing system

Revision of the storage tank

Starting work on adjusting the equipment, disconnect the system from the network, close the pressure valve on the side of the water intake. The tap is unscrewed and the water is drained, and the remnants are drained through the pressure hose, disconnecting it from. First, check the air pressure in the accumulator tank.

The role of the accumulator in the operation of the system

The membrane tank of the pumping station is, in fact, a metal container with a rubber pear located inside, which is designed to collect water.

Air is pumped into the free space between the rubber bulb and the walls of the tank. In some models of hydraulic accumulators, the tank is divided in half by a membrane that delimits the tank into two compartments - for water and air.

The accumulator tank maintains pressure in the system and creates a small supply of water. Once a month, the pressure in the hydropneumatic tank should be checked with the pump turned off and the water drained from the supply pipe.

The more water enters the device, the more it compresses the air, increasing its pressure, which tends to push the water out of the tank. This allows you to maintain a stable water pressure even when the pump is idle.

The accumulator requires regular maintenance, removal of air from the pear, which enters it along with water in the form of small bubbles and gradually accumulates there, reducing the usable volume.

For this, a special valve is provided on top of large tanks. With small containers, you have to contrive to remove air: de-energize the system and drain and fill the tank several times.

The selection of a hydraulic tank by volume is made taking into account the highest value of water consumption for a particular consumer. The allowable number of starts per hour specified by the manufacturer is taken into account, as well as the nominal values of the cut-in pressure, cut-out pressure and user-specified pressure in the hydraulic tank

Air pressure control

Although the manufacturer adjusts all elements of the pumping station at the production stage, it is necessary to double-check the pressure even in new equipment, since at the time of sale it may decrease slightly. The device that is in operation is inspected up to two times a year.

For measurements, the most accurate pressure gauge is used, because even a small error of 0.5 bar can affect the operation of the equipment. If it is possible to use a car pressure gauge, with a scale, with the smallest graduation, this will provide more reliable results.

The air pressure indicator in the membrane tank must correspond to 0.9 times the switching pressure of the pumping station (set using a relay). For tanks with different volumes, the indicator can be from one to two bar. Adjustment is carried out through the nipple, pumping or bleeding excess air.

For normal operation, the station is equipped with mandatory control and regulation devices:

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The less air is pumped into the system, the more water it is able to accumulate. The water pressure will be strong when the tank is full, and more and more weakened when water is taken.

If such drops are comfortable for the consumer, then the pressure can be left at the lowest acceptable level, but not less than 1 bar. A lower value can cause the bulb filled with water to rub against the tank walls and damage it.

To install in a strong water pressure, it is necessary to fix the air pressure in the range of about 1.5 bar. Thus, the difference in pressure between a full and empty tank will be less noticeable, providing an even and strong flow of water.

Using a pressure switch

Responsible for the automation of the system is a device that controls the pumping station, performing the function of turning the device on and off. It also prevents the system from building up excessive pressure.

The pressure switch controls the on/off cycles when a user-defined operating pressure is reached. The performance of the pressure switch is controlled by a pressure gauge

#1: Working principle of the pressure sensor

The main element of the relay is a group of contacts, which is fixed on a metal base and is responsible for turning the device on and off.

Nearby are two springs different sizes to regulate the pressure inside the system. From below, a membrane cover is attached to the metal base, under which the membrane itself and a metal piston are located. From above everything is closed with a plastic cap.

There are several stages in the operation of the operating device:

When you turn on the tap, water for some time flows to the plumbing point from the filled tank. In this case, the pressure present in the system gradually begins to fall, and the membrane stops pressing on the piston. The contacts close, the pump turns on.
The pump works by pumping water to the consumer, and when all the taps are turned off, it fills the tank with water.
With the gradual filling of the accumulator tank, the pressure increases, and it begins to act on the membrane, and it presses on the piston. As a result, the contacts open and the pump stops.

The frequency of switching on the station, the pressure of the water, and even the service life of the equipment depend on how the relay is configured. If the parameters are set incorrectly, the pump will not work at all or will work continuously.

The pressure switch piston and a sensitive metal plate that reacts to the pressure created by the hydraulic tank membrane are hidden under the housing - access to them is completely closed

#2: Adjusting and calculating the required pressure

The new device already has factory relay settings, but, nevertheless, it is better to check them additionally. Before setting up, you need to find out the values recommended by the manufacturer for setting the allowable pressure threshold (for closing and opening contacts).

In case, due to incorrect adjustment, the manufacturer has full right waive their warranty obligations.

The calculation of the allowable pressure, when turning the device on and off, is carried out by the manufacturer, taking into account the expected features of operation. They are taken into account in the development of operating parameters for different models pumping stations.

The inclusion value is equal to the sum of:

required pressure in the most high point plumbing system where water is taken;
Differences between the height of the highest point of water extraction and the pump;
Losses in the water pressure pipeline.

The turn-off rate is calculated as follows: plus one bar to the turn-off pressure and subtract one and a half bar. In this case, the shutdown pressure must not be allowed to exceed the maximum allowable pressure that occurs at the outlet of the pipeline from the pump.

A common mistake that affects the operation of a pumping station is not taking into account the entire amount of horizontal and vertical sections, as well as hydraulic losses during the transportation of water to draw-off points.

Before changing the settings, it is necessary to fix the previous readings using a pressure gauge. Turning on the pump, record the pressure at the time of turning it off and on. This will help determine in which direction to carry out the adjustment - in the direction of decreasing or increasing.

It must be remembered that any change in the set pressure threshold in the relay also requires corresponding changes in the air compartment of the accumulator.

The next steps are in the following order:

Disconnect the station from power, drain the water and open the relay cover with a wrench.
The switching pressure of the pump is adjusted by turning the nut that holds the large spring (P). By twisting it in a clockwise direction, they achieve compression of the spring and installation required pressure inclusions. V various models device allowable indicators can range from 1.1 to 2.2 bar.
By turning the small nut (∆P) clockwise, you can increase the gap between the switch-off and switch-on pressure of the device, which is usually 1 bar. Thus, the shutdown pressure can be fixed at values in the range from 2.2 bar to 3.3 bar.

An important nuance is that the small spring does not adjust the shutdown threshold, as some mistakenly understand.

It sets exactly the delta between the values of switching on the station, and its shutdown. That is, a fully relaxed spring will not create a difference - the delta will be zero and the on and off values will be the same. But the more you tighten it, the greater the difference between them will be.

The small pressure switch spring is more sensitive and must be compressed very carefully

Check the correctness of the set indicators using a manometer. If it was not possible to achieve the required values on the first attempt, the adjustment is continued.

#4: Select non-standard pressure values

You can set a different level of pressure in the device, different from the recommendations of the manufacturer, adjusting the equipment to the individual needs of the user. By increasing the range when turning on / off, they achieve more rare station operations.

This makes the service life of the device longer, but gives the water pressure an uneven character. By reducing the difference, they achieve a stable pressure, but this way the pump will work more often.

Conclusions and useful video on the topic

How to adjust the pressure of the station, the video will demonstrate:

Video on what to do if the station often works:

Conducting self-adjustment pumping station, it must be taken into account that sometimes changes in factory recommendations can worsen the operation of the plumbing system. The pump, hoses, plumbing fixtures - all have pressure limits, the violation of which will lead to breakdowns. Therefore, before starting independent action, it is better to ask for advice from an experienced specialist.

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