Adjusting the pressure switch for the pump: setting + connecting the relay to the pump

The pressure switch is a small but indispensable unit of a large and small pumping station. And if all the rest of its elements just need to be properly connected, then it will also have to be further configured. This device is responsible for automating the pumping process. It turns the equipment on and off according to the pressure in the hydraulic tank.

Properly performed adjustment of the pressure switch for the pump - a guarantee of comfort and long service life of the equipment. We describe in detail in the article how it is carried out, what actions need to be taken and what data to know for fine tuning. You will learn why and in what situation it is produced.

In addition to the step-by-step description of the adjustment procedure, we provide valuable recommendations provided by hydraulic engineers. To optimize perception, the text is supplemented with photo clips, diagrams, video tutorials.

Features of the device and the principle of operation

Numerous varieties pressure switchwhich is completed with almost all pump stations, are arranged approximately equally.

Inside the plastic case there is a metal base on which other elements are fixed:

• membrane;
• piston;
• metal platform;
• electrical contact node.

On top of the plastic cover are two springs - large and small. When the membrane is under pressure, it pushes the piston.

He, in turn, lifts the platform, which acts on a large spring, squeezing it. A large spring resists this pressure, limiting the movement of the piston.

A small distance, which separates the large and small adjustment springs, is enough to regulate the operation of the whole complex 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.

This causes the switching of contacts, which changes the mode of operation of the pump, and it turns off. There is a special hinge with a spring for switching contacts.

When the platform overcomes the level at which this hinge is located, the electrical contacts change position by opening the power supply circuit. At this point, the pump is turned off. After that, the water stops flowing and the pressure exerted on the membrane decreases as water is used up from the hydroaccumulator.

Accordingly, the platform smoothly lowered. When its position is lower than the spring hinge of the electrical contacts, they rise, turning on the power supply again.

The pump pumps water into the hydraulic tank, the relay membrane presses against 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 a small determines the “ceiling” of the allowable pressure in the system, as you might think, but the difference between these two indicators. This is an important point, which is useful when studying the procedure for pressure switch setting own pump.

Do you need a setting at all?

Of course, independently or with the help of a specialist, but it will be necessary for everyone who has assembled his pumping station from individual elements to adjust the pressure relay.

There is an opinion that ready-made pumping stations, purchased in assembled form, are equipped with a pressure switch already configured and prepared for operation. In practice, this is not always the case.

Each plumbing system has individual characteristics. Yes, and the needs of tenants may be different.

Constant head system for homein which there is only a shower cabin, kitchen sink and bathtub, significantly different from the needs of a spacious cottage with a jacuzzi and hydro-massage. Factory settings correspond to the real situation is not always.

In addition to setting the pressure switch when installing the pumping station, it is also necessary to periodically check and correct its operation.

The same operation will have to be repeated if some part of the pumping station has failed, has been repaired or replaced. The procedure for adjusting the equipment is almost the same as the procedure for setting it up.

General terminology of indicators

When configuring the pressure switch, some specific names are used. They are well understood by a specialist, but a beginner can be confused. It is better to immediately understand their essence, so as not to get confused during the execution of works.

These terms are:

• firing pressure;
• off pressure;
• pressure drop;
• maximum shutdown pressure.

Shutdown pressure is usually referred to as P_off. Sometimes this indicator is also called top pressure. This indicator, as the name implies, indicates the pressure at which the pump starts or resumes operation, and water begins to be pumped into the hydraulic tank. Usually, the manufacturer defaults to a lower pressure of 1.5 bar.

The inclusion pressure is also called the lower pressure by analogy and is designated as Rvkl. This is the second granite indicator, on a relay coming from the factory, usually about 3 bar or a little less.

The pressure drop or delta (ΔP) is calculated as the difference between the lower and upper pressure. In the standard model of the pressure switch, this indicator is usually about 1.5 bar before adjustment.

The maximum, or rather the maximum allowable value of the pressure off allows you to get an idea of ​​the maximum pressure in the system. Exceeding this indicator can cause significant damage to the water supply and equipment. Usually this figure is about 5 bar or a little less.

Pressure in the hydroaccumulator

Understanding of how does the hydroaccumulator, will help to better cope with self-tuning control equipment.

There are two types of hydraulic tanks: with a rubber insert resembling a sadness, or with a rubber membrane. This element divides the container into two non-communicating parts, in one of which there is water, and in the other - air.

In any case, they work about the same. Water enters the tank, and a rubber insert presses against it to ensure the movement of water through the plumbing system.

Therefore, a certain pressure is always present in the hydraulic tank, which varies considerably depending on the amount of water and air in the tank.

On the body of the tank there is usually a car nipple. Through it you can pump air into the hydraulic tank or bleed it to adjust the working pressure inside the tank.

When connecting the pressure switch to the pump, it is recommended to measure the current pressure in the hydraulic tank. The manufacturer defaults to 1.5 bar. But in practice, part of the air usually leaves, and the pressure in the tank will be lower.

To measure the pressure in the hydroaccumulator, use an ordinary automobile gauge. It is recommended to choose a model with a scale on which the smallest gradation step is affixed. Such a device will allow for more accurate measurements. It makes no sense to measure the pressure, if it is not possible to take into account one-tenth of the bar.

In this regard, it makes sense to check the pressure gauge, which is equipped with a pumping station of industrial production.

Often, manufacturers save and install low-cost models. The accuracy of measurements using such an instrument may be questionable. It is better to replace it with a more reliable and accurate device.

Mechanical automotive gauges do not look very presentable, however, judging by the reviews, they are much better than modern electronic devices. If, however, the choice is made in favor of the electronic manometer, it should not be saved. It is better to take a device manufactured by a reliable manufacturer than a cheap plastic craft that does not give accurate data and can break at any time.

Another important point - the electronic pressure gauge requires power, this will have to be monitored. Check the pressure in the hydraulic tank is very simple.

The gauge is attached to the nipple and measure readings. Normal is the pressure in the range from one to one and a half atmospheres. If the pressure in the hydraulic tank is too high, the water supply in it will be less, but the pressure will be just great.

It should be remembered that too high pressure in the system can be dangerous. In this case, all components of the water supply system are constantly working under increased load, and this leads to rapid equipment wear. In addition, in order to maintain an elevated pressure in the system, it is necessary to pump water into the tank more often, and therefore turn on the pump more often.

It is also not very useful, since the probability of breakdowns increases. When setting up the system, a certain balance is needed. For example, if pressure in the hydroaccumulator too high or too low, it may damage the rubber gasket.

How to properly configure the relay?

There is a lid on the pressure switch housing, and under it are two springs fitted with nuts: large and small. Rotating these springs, establish the lower pressure in the hydroaccumulator, as well as the difference between the values ​​of the on and off pressure. The lower pressure is regulated by a large spring, and a small one is responsible for the difference between the upper and lower pressure.

Before starting the adjustment, it is necessary to study the technical documentation of the pressure switch, as well as the pumping station: hydraulic tank and its other elements.

The documentation indicates the operating and limit values ​​for which this equipment is designed. During the adjustment, these indicators should be taken into account in order not to exceed them, otherwise these devices may soon break down.

Sometimes it happens that during the setting 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 is simply not enough to bring the hydraulic tank or system to the limit.

It is useless to adjust the relay if the accumulator is filled with water. In this case, not only the water pressure, but also the parameters of air pressure in the tank will be taken into account.

To adjust the pressure switch, you must perform the following steps:

1. Set the working air pressure in the empty hydroaccumulator.
2. Turn on the pump.
3. Fill the tank with water until the lower pressure is reached.
4. Turn off the pump.
5. Rotate the small nut until the pump starts.
6. Wait until the tank is full and the pump is turned off.
7. Open the water.
8. Rotate the large spring to set the switch pressure.
9. Turn on the pump.
10. Fill the hydraulic tank with water.
11. Correct the position of the small adjusting spring.

The direction of rotation of the adjusting springs can be determined by the signs “+” and “-”, which are usually located nearby. To increase the switching pressure, the large spring should be rotated clockwise, and to reduce this figure, it is rotated counterclockwise.

The rotation of the adjusting springs during the adjustment of the pressure switch for the pump must be performed very smoothly, about a quarter or half a turn, these are very sensitive elements. The manometer, when restarted, should show a lower pressure.

With regard to performance when adjusting the relay, it will be helpful to remember the following points:

• If the hydraulic tank is filled and the 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 pressure off and on pressure is about 1-2 atm., It 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 hydraulic accumulator is 0.1-0.3 atm.
• In the accumulator the air pressure should not be less than 0.8 atm.

The system can regularly turn on and off in automatic mode and with other indicators. But these boundaries make it possible to minimize the wear and tear of equipment, for example, the rubber liner of the hydraulic tank, and to extend the operating time of all devices.

Some tips and advice

For normal functioning pumping station It is recommended to measure the air pressure in the hydroaccumulator every three months. This measure will help maintain stable settings in the operation of the equipment. A sharp change in performance may indicate some kind of breakdown that needs to be fixed.

To quickly monitor the state of the system, it makes sense to just from time to time record the readings of the water pressure gauge when the pump is turned on and off. If they correspond to the figures set during the setup of the equipment, it is possible to consider the operation of the system to be normal.

The noticeable difference suggests that you need 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 gauge has a certain error. In part, this may be due to the friction of its moving parts during measurements. To improve the reading process, it is recommended to additionally lubricate the pressure gauge before starting measurements.

Pressure switches, like other mechanisms, tend to wear out over time. Initially, choose a sturdy product. An important factor in the long-term operation of the pressure switch is the correct setting. Do not use this instrument at the maximum allowable upper pressure.

It should leave a small margin, then the elements of the device will not wear out so quickly. If it is necessary to set the upper pressure in the system at a sufficiently high level, for example, at five atmospheres, it is better to purchase a relay with a maximum allowable working value of six atmospheres. Finding such a model is more difficult, but it is quite possible.

Serious damage to the pressure switch may be caused by contamination in water pipes. This is a typical situation for old water pipes made of metal structures.

Before installing the pumping station, the water supply is recommended to be thoroughly cleaned. It does not hurt and complete replacement of metal pipes for plastic construction, if there is such an opportunity.

When adjusting the relay to the adjusting springs should be treated with extreme care. If they are too tight, i.e. twisted during the setup process, errors will occur very soon when the device is working. Relay failure in the near future is almost guaranteed.

If during the testing of the pumping station operation there is a gradual increase in the shutdown pressure, this may indicate that the device has become clogged. Do not immediately change it.

It is necessary to unscrew the four mounting bolts on the pressure switch housing, remove the diaphragm assembly and thoroughly flush the inside of the relay, where possible, as well as all small holes.

Sometimes it is enough just to remove the relay and clean its openings from the outside without disassembling. It also does not hurt to clean the entire pumping station. If water suddenly begins to flow directly from the relay casing, it means that the particles of impurities have pierced 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 the pressure switch:

Adjusting the pressure switch is not always easy. We must act carefully and carefully. But the understanding of 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 a pressure switch, operating a pumping system equipped with an instrument. Perhaps you have questions in the process of familiarization with the material? Ask them and comment on the article in the box below.