The pressure switch is a key element in pump automation or pumping station, it gives a signal to turn on and off the pump. Depending on the manufacturer and model, the factory settings may differ, but, as a rule, the lower threshold for switching on the pump is set to a pressure of 1.4–1.8 bar, and the threshold for switching off is 2.5–3 bar. But sometimes such threshold settings are not sufficient for the normal operation of plumbing fixtures, therefore it is necessary to adjust the water pressure switch for the pump , to select the individual parameters for enabling and disabling it.

Design and principle of operation

Before you start configuring the relay, you need to understand the design and principle of its operation. The design of the relay is quite simple and consists of contacts spring-loaded by a plate on which water pressure acts.

1. Frame.
2. Contact group for connecting the pump.
3. Terminals for connecting to the power supply.
4. Grounding terminals.
5. Nut for connecting the relay to the water supply.
6. Differential pressure adjustment spring.
7. Spring for adjusting the minimum pressure.
8. The assembly where the piston and diaphragm are located.

On a metal base, a metal platform is fixed at one end, which can be raised and lowered under the action of a piston. The piston is driven by water pressure. There are two springs (6,7) installed on the platform, a large spring (7) counteracts the force of the piston (water), thereby balancing it. The small spring (7) does not come into action immediately, but after the platform rises to a certain height, and as soon as the platform touches the smaller spring, the forces of both springs begin to oppose the piston and the resistance to the piston force increases, from this moment the platform needs to rise quite a bit. so that the contacts open and the pump stops. A small hinge with a spring is responsible for opening and closing the contacts. As soon as the platform rises above this hinge, the contacts bounce down and the electrical circuit is opened, as soon as the action of the force of the piston (water) weakens, the platform drops down and the contacts close.

A large spring is responsible for turning on the pump, that is, for the lower pressure limit, and with the help of a small spring, the moment of turning off the pump is adjusted, or rather, the difference between turning on and off is set.

Customization

Based on the operating principle of the relay, its setting consists in changing the stiffness between the platform, which is acted upon by the water pressure and the contacts. The adjustment is carried out by changing the stiffness of the spring, which is either compressed or loosened by adjusting nuts. Before starting the adjustment, you need to fix the pressure gauge indicators while turning the pump on and off. Next, disconnect the relay from the network, and remove the housing cover. Using a wrench, unscrewing or tightening the nuts, set the required parameters:

• if it is only necessary to change the lower switching threshold (increase or decrease), then you need to press or release the nut on the spring (7);
• to increase or decrease the upper limit of the pump shutdown, you need to screw or unscrew the nut on the spring (6), when tightening, we raise the pump shutdown limit, and when unscrewing, on the contrary, we lower it, increasing the difference between on and off;
• if you need to change two parameters at once, then first the lower limit is adjusted using the spring (7), and then we set the difference using the spring (6);

All changes must be monitored with a pressure gauge. It is worth considering that by changing the pressure difference, we reduce or increase the duration of the pump operation, and this will be reflected in the change in pressure in the water supply network. If the pressure difference is small, then the pressure in the network will be "even" without visible differences, but the number of pump starts will increase, which may affect its service life.

When making adjustments, it must be remembered that the upper pressure should not be higher than the maximum pressure that the pump can create (you can see it in the pump's passport characteristics). The upper pressure should not exceed more than 80% of the maximum allowable pressure for a particular model, and these parameters are indicated in the instructions for the relay. Also, before adjusting, you need to check the air pressure in the tank pear - it should be less than the lower threshold for switching on the pump by 0.2 bar. Another regulation requirement is the switch-on and switch-off pressure difference, it must be in the range of 1-1.5 bar. When changing the parameters, it is impossible to tighten the nuts all the way, this can lead to the fact that the relay will stop working altogether.

Video

This video shows how to adjust the pressure switch for a pump:

A pressure sensor is a mechanical device that is responsible for controlling the operation of a pressure plant. The device measures changes in fluid pressure, turns on or off pressure technology. When the accumulator tank begins to fill with water, the pressure decreases, the sensor is triggered and activates the pump itself.

A pumping station (hydrophore) is a complex structure for pumping water from one place to another. It doesn't matter if you have a well or a well, you use a submersible pump or a borehole, the installation of pumping stations greatly facilitates the water supply system of private households. It is customary to complete pumping units with additional equipment that allows you to adjust the water pressure as you need.

1 Purpose and function of parts of the pressure plant

A properly tuned and regulated pump (or pumping station) with a pressure switch, heat sensor, pressure gauge and timer - this is the hydrophore, i.e. complex of a full-fledged pressure plant. The complete set consists of:

• pump;
• temperature sensor;
• pressure gauge;
• non-return shut-off valve systems;
• piping systems;
• timer;
• and, in fact, the pressure switch itself to the pump.

A thermal relay protects the electric pump from overheating. The signal about overheating of the mechanisms comes due to the deformation of the metal fuse plates after reaching the maximum allowable temperature set by the system initially.

Heat sensors are made of stainless steel and anti-corrosion materials. Their body is sealed, all connecting mechanisms and parts are threaded. Heat sensors are attached through connectors of the Din 43-650 type.

A time relay (timer) is a mechanism with which you can set the required time intervals for turning on and off equipment.

A pressure gauge is a mechanical or automatic device for measuring pressure in closed systems. Its various modifications are used for water, gas, steam, and other substances.

2 Design and principle of operation of the relay

The pressure switch for the pump is factory set to one and a half atmospheres by default. The water pressure switch for a "normally closed" pump means that at zero pressure the contact in the apparatus is closed.

To configure the pressure switch to control the pump, you must first disassemble the device. To remove the case, use a slotted screwdriver to remove the bottom screw. The internal structure is extremely simple:

• large diameter spring;
• small diameter spring
• terminals for connecting wires.

2.1 How to connect a pumping station relay?

The pressure switch is connected as follows. In two wide sockets, you need to connect the wires from the network and the pressure apparatus itself. The pump connection diagram is always included in the instructions for the product. The relay is connected to the system through the connecting pipe. The pipes themselves in designs are with an external thread or an internal one. Standard size threads (diameter) 14 inches.

The reverse side of the regulator (the so-called pipeline connection unit) looks like this: a metal plate with a screw-threaded hole (large nut) on four screws, under which a piston with a diaphragm is fixed.

When water triggers the piston, it lifts the diaphragm and forces the spring to work (compress and expand). Therefore, if your regulator has been operating for some time, different kinds dirt, sand, rust, suspensions and so on, depending on the type of soil on which the hydrophore is installed.

2.2 How to set up a water flow switch for a pumping station?

Adjustment of the pressure switch of the pumping station begins with the installation of the correct connections of the regulator itself to the point of the accumulator or next to it. It is necessary to set up a pumping station based on a clear knowledge of the parameters of the hydrophore. Again, the factory default is configured like this:

• 1.5 bar to switch on;
• 3 bar - shutdown;
• 5 bar maximum admissible pressure.

The whole cycle of the installation looks like this. With a full tank of water, the connected unit starts supplying water to the pipeline system, the pressure in the pipes gradually decreases. We observe this process on the pressure gauge. At the moment when the water level drops to the lower limit value, the contacts inside the device should close. At this moment, the pump starts up.

Until the taps close, water enters the house due to the work of the pressure pump mechanism. When the taps are closed, the pump pumps a full hydraulic tank of water and should stop. The pressure in the system builds up again, and when it reaches the set level, the contacts of the regulator open again and the pump turns off.

As you can see, the process is simple enough that even a non-professional could figure it out. However, it should be remembered: carefully look at the complete set of your pressure plant and the model of equipment that you are using. The manual always contains recommendations on which installations are combined with one or another equipment.

For example, for borehole pump it is only worth choosing a water pressure switch for a pump with a diameter of 9cm (this is the so-called nine). Variants of these are made by the companies Aquarius, Grundfus and Aquaria. For screw pressure devices, many manufacturers supply their own control panel in the kit, so if you wish, you can do without installing a sensor.

The consequences of a sensor failure can be very diverse. From the non-stop operation of the hydrophore, to the boiling of water in the installation, which will lead not only to additional energy costs, but also to the failure of internal parts. Oil seals, for example, in case of boiling water in the pump will have to be changed. If the problem is not noticed and solved in time, you can generally be left without a hydrophore.

2.3 Adjusting the pressure switch of the pumping station (video)

How to set up the pressure switch of the pumping station.

Hydrophore pressure regulation

Pressure switch- it is an integral part of the pumping station (hydrophora), which ensures its automatic operation. By closing and opening the contacts, the relay controls the activation and deactivation of the pump.

The relay has two characteristics:

• Shutdown pressure (bar) - "upper" pressure at which the pumping station is shut down. Approximate value 2.5 - 3 bar;
• Switch-on pressure (bar) - “lower” pressure at which the pumping station is switched on. Approximate value 1.5 - 1.8 bar.

As a rule, the pressure switch is already optimally set on the pumping stations supplied as an assembly. However, when assembling a station from individual elements(pump, tank, pressure gauge, etc.), relay setting is mandatory.

To adjust the pressure, two bolts are provided, which are located under the relay cover.

The “lower” switch-on pressure is adjusted with a large bolt # 1. Turn the bolt clockwise to increase the pressure, turn it counterclockwise to decrease it.

The “upper” shut-off pressure is adjusted by small bolt # 2. By turning the bolt clockwise, we increase the pressure, turning it in the opposite direction, we reduce it.

The process of setting the pressure switch at the assembled pumping station itself consists of two steps:

1) Determination of the air pressure in the expansion vessel

The air pressure must be determined with an empty tank and the station disconnected from the power supply!

A pear-shaped rubber diaphragm is installed in the expansion tank, into which the pump pumps water. There is pressurized air between the diaphragm and the metal body of the tank. To determine the pressure, as well as for pumping or venting air, a special valve (nipple) is provided in the back of the tank. The air pressure in the tank is measured with a pressure gauge designed to measure the pressure in car wheels. If necessary, air is pumped with an automobile pump.

For tanks with a volume of 20-25 liters, the air pressure should be 1.4 - 1.7 bar, and 1.7 - 1.9 bar for tanks with a capacity of 50 - 100 liters.

There must always be air in the tank. Its pressure must be checked periodically (once a month) and maintained at the recommended values, which will have a positive effect on the service life of the rubber diaphragm and the comfort of using the pumping station as a whole.

2) Determination and adjustment of the pressure on and off the pumping station

After adjusting the air pressure, the pumping station must be connected to the network. The pump will start pumping water into the tank and shut off when the set pressure is reached. This will be the “high” pressure and will be displayed on the gauge. If this value differs from the recommended one, then adjust it using the relay bolt No. 2 (see fig.).

The "lower" pressure is measured in the same way. After opening the tap and starting to drain the water, observe the pressure gauge. The pressure will gradually drop and when the lower limit is reached, the pump will turn on again. The pressure value on the manometer at the moment the pump is turned on will be the "lower" pressure. If necessary, adjust it to the recommended parameters using the relay bolt No. 1 (see figure).

It is important to know that the pump start pressure must be 10% higher than the air pressure in the tank! Failure to do so can lead to accelerated wear of the rubber diaphragm.

You can set on the relay and other, different from the recommended, values ​​of the on and off pressure, thereby adjusting the pumping station to your own level of comfort. By increasing the difference between "top" and "bottom" pressure, you can extend the life of the pump due to less frequent pump starts. However, the pressure in the system will be uneven. As the difference between the "upper" and "lower" pressure decreases, the pump will turn on more often, but the pressure in the system will be constantly even and comfortable.

When setting up a pressure switch, it is also important to remember that the hydraulic accumulator, plumbing, rubber hoses and the relay mechanics itself have their own pressure limit values ​​that should not be exceeded.

Electrical connection of the relay

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The pressure switch for the pump controls the operation of the entire station. After all, it is the relay that turns on the pump when the pressure in the accumulator drops (and turns it off when the pressure rises to a critical level). As a result, even a small failure in the operation of the relay affects the functionality of the entire autonomous water supply system.

However, any failure in the operation of the relay can be eliminated with the help of the simplest adjustment. And in this article we will analyze both the adjustment process and the procedure for connecting and initial setting the pressure switch.

The pumping station consists of a hydraulic accumulator (sealed water storage), a unit (centrifugal or vibration pump) and a pressure switch regulating the operation of these units.

Moreover, the principle of operation of the relay is determined by the operating scheme of the station itself, which looks like this: turning on the pump - filling the accumulator - turning off the pump. Well, when it is necessary to turn on and off the pump, it is the pressure switch that determines.

Moreover, the process of making a decision to turn on or off the unit is based on monitoring the following values: the minimum and maximum pressure in the accumulator. In addition, the operation of the relay is also influenced by such characteristics as the difference between the minimum and maximum pressure and the maximum allowable pressure in the accumulator.

The first value is the minimum pressure, as a rule, equal to 1.5 atmospheres. That is, when the pressure in the accumulator drops below the designated 1.5 atmospheres, the pump will be activated (by closing the contacts in the pressure switch).

The second value is the maximum pressure, as a rule, does not exceed 4 atmospheres. That is, when the pressure in the accumulator rises to 4 atmospheres, the pump is disconnected from the power supply (by opening the relay contacts).

Accordingly, the difference between the minimum and maximum pressure (at the factory setting of the relay) is 2.5 atmospheres. Moreover, when adjusting the pressure, they operate with this very characteristic, setting the desired difference from the minimum indicator.

The maximum allowable pressure in the storage tank is 5 atmospheres. That is, if the pressure in the accumulator reaches five atmospheres, then the pump will turn off in any case (for any value of the pressure difference).

Initial adjustment of the water pressure switch

The initial adjustment of the relay is carried out at the plant of the company that produces the pumping stations. Actually, therefore, all the "default settings" (1.5 atmospheres of minimum pressure and 2.5 atmospheres of difference) are called "factory".

However, the connection of the pressure switch to the pump (with the introduction of factory settings) is carried out at the last stage of the station assembly. And the sale of the unit will take place a long time ago. And over the past months from the moment of manufacture to the moment of sale, the springs and diaphragms of the relay and accumulator may weaken.

Therefore, for a pump you just bought, it is worth checking the pressure in the accumulator and the minimum and maximum pressure values ​​set at the factory.

Well, the drive itself is checked as follows:

• A pressure gauge is connected to the nipple of the accumulator or tank. Moreover, in this case, you can use a conventional automobile device, with which the tire pressure is checked.
• An arrow on the pressure gauge will indicate the air pressure behind the empty cylinder diaphragm. And this value cannot be less or more than 1.2-1.5 atmospheres.

If the pressure gauge shows a higher value, then the air from the tank is "bled", but if it is less, then the tank is "pumped up" by a car pump. Indeed, the "starting" indicator of the relay (minimum pressure) will depend on the pressure level behind the membrane.

After checking the pressure in the hydraulic tank or accumulator is completed, you can start examining the pressure switch, during which the actual values ​​of the minimum and maximum pressure are compared with the values ​​set on the control unit.

Moreover, this operation is very simple, namely:

• A pressure gauge is attached to a manifold mounted on the neck of a tank or accumulator.
• Then the pump is turned off and the drive is emptied (by opening the tap). The pressure on the gauge should drop to 1.5 atmospheres.
• After that, close the tap and turn on the pump. The pump should raise the pressure in the tank to the maximum value and turn off. After turning off the pump, you need to compare the pressure on the pressure gauge with the factory values ​​declared in the passport.

If the actual values ​​on the pressure gauge do not coincide with those declared in the passport, or the factory settings do not meet the needs of the consumer, then in this case, an individual adjustment of the relay is required. We will discuss the nuances of the individual customization process below in the text.

How to customize the pressure switch for individual needs

Individual configuration or reconfiguration of the relay operation after a failure is carried out as follows:

• At the very beginning, you need to open the relay case by disconnecting the protective cover from the base. After all, it is under the casing that the contacts of the electric motor and the control units of the relay are "hidden": a stud with a large nut holding a large spring and a stud with a small nut holding a small spring. In this case, the tension of the large spring controls the minimum pressure, and the small spring - the pressure difference.
• The adjustment of the "starting" (minimum) pressure begins with an empty accumulator. Moreover, to free the accumulator from liquid, it is enough just to turn off the pump and open the tap. The adjustment itself is carried out as follows: the large spring is completely weakened (the nut is unscrewed counterclockwise), then the pump should be turned on and gradually tighten the spring. At the moment when the pump starts working and starts pumping water, manipulations with the large nut are stopped - the minimum pressure has reached the pressure mark in the air part of the accumulator plus 0.2-0.3 atmospheres. And if there is 1.2-1.3 atmospheres behind the accumulator membrane, then the minimum pressure in the tank will approach the desired 1.5 atmospheres. Well, who wants more - he must, at the beginning of the adjustment, "add" the pressure in the accumulator (by pumping air through the membrane).
• Differential pressure adjustment is even easier. You just need to wait for the pump to stop and read the indicator from the pressure gauge on the accumulator manifold. If the result is not satisfactory, the pump is turned off, the water is drained, and a small nut is tightened (to increase pressure) or unscrewed (to decrease pressure) onto a pin with a small spring. After that, the pump is turned on and the "new" upper pressure obtained after the adjustment is read.

It should be remembered that an excessively large minimum pressure "kills" the membrane of the accumulator. Therefore, it is strongly discouraged to raise the minimum threshold above the "factory" 1.5 atmospheres.

The water pressure switch is designed to control the pumping unit and maintain the pressure in the water supply network of the house at a given level. The pressure switch is very important element and its installation and configuration must be done professionally. The entire water supply system, the safety of its functioning and the performance of other units in the system depend on the quality of the pressure switch.

The principle of operation of the pressure switch (pump control sensor)

The relay registers the water pressure in the system with a movable spring group. When the specified minimum pressure is reached, the contact closes, turning on the pumping unit. When the maximum set pressure is reached, the contact opens and the pumping unit turns off. The pressure switches are equipped with adjusting mechanisms that allow you to adjust the pressure values, and they can additionally be equipped with a "dry" forced start button, soft start equipment for the pump, additional connectors instead of terminal groups for connecting the pump, operation indication, etc.

Place for pressure switch installation

It is recommended to install a pressure switch directly at the outlet to the accumulator, where pressure surges and flow turbulence during pump start-up and operation are largely neutralized. Also, for individual models, manufacturers limit the operating conditions for the microclimate, namely, the temperature is not lower than +4 degrees. and humidity not higher than 70%. Such relays should be installed in a heated room.

Before the pump control sensor (pressure switch) in the water supply system, the following must be installed:

• Filter rough cleaning water
• Pump and piping
• Inlet valve
• Filter fine cleaning water
• Check valve
• Draining to the sewerage system

The installation option for a pressure switch in the water supply system of a house is shown in the figure.

Modern pump models are equipped with special fittings for connecting a pressure switch, as well as built-in filters and a non-return valve. Therefore, separate pressure switches can also be mounted directly in the pump unit. If the relay is made according to a waterproof scheme, then it can be installed with a pump and in a caisson (pit) and even directly in a well. It all depends on the chosen model and the manufacturer's recommendations for temperature and humidity.

Determination of work parameters

Before choosing a pressure switch, a pumping unit and a hydraulic accumulator must already be selected, and the operating parameters of the network must be determined:
- the maximum pressure in the system at which the pump will be turned off;
- the minimum pressure at which the pump will turn on;
- pressure in the air chamber of the accumulator.

Please note that the minimum working pressure in the water supply system should be 0.2 atm more than the pressure in the air chamber of the accumulator. Otherwise, increased wear of the elastic membrane is possible.

Please note that the relay can be:
- power, - including power contacts to the pumping unit;
- control, - issuing a signal to the power control unit.

Check for what permissible switching power the relay is designed. And how this value relates to the selected pumping unit.

Design features and pressure setting

A pressure switch of a simple design is a small device that is equipped with a union for connecting to a water pipe and a terminal group for connecting electrical cables... The registration of pressure parameters is carried out using springs, the force of which is adjusted by threaded regulators.

The more the springs are compressed by the regulator, the more force they create, and the higher the pressure is required to operate the relay (large spring), or the greater the pressure difference must be (small spring). Those. by clamping the springs we increase the values.

Typically, pressure switches designed for household use have a factory spring setting that is fully suitable for living conditions applications and common models of pumps and accumulators. For example, the minimum pressure is 1.5 atm. The maximum pressure is 3.0 atm.

However, due to some factors (considerations), sometimes it becomes necessary to adjust the pressure.

Adjusting the pressure switch for the pump

• Relays are usually equipped with two springs with different diameters.
• A large diameter spring controls pressure levels.
• Small diameter spring - determines the level difference.
• By clamping a large spring, we increase the minimum and maximum pressure at the same time.
• By clamping a small spring, we increase the superiority of the maximum pressure over the minimum.

The video shows the process of adjusting the pressure on the relay (somewhat confusing explanations about the purpose of the springs should not be misleading, and understanding the difference between the readings of the pressure gauge and the voiced results should help psychological stability observing)

Water pressure switch connection

The video presented shows the popular models of pressure switches, their characteristics and connection nuances are announced. Happy viewing.