It is impossible to imagine the operation of pumping equipment without automation - if you do not connect it, the pumps that suck up water from the depths of wells and wells will operate continuously until the electric motor winding overheats and burns out. Due to the massive housing, surface models of electric pumps are not so sensitive to overheating and can operate for a long time in the absence of water in the system; submersible types without water cooling of the housing fail within a very short time. The main element in the automatic control system for the operation of all types of pumps is a pressure switch installed on the surface in the water main.
Rice. 1 Different kinds pressure switch for water mainIn an automation system, the relay performs several functions:
- Serves to automate the operation of pumping equipment, turning on the electric pump at low pressure in the system and turning it off when the pressure rises to a given level.
- Protects the electric pump from overheating, preventing its continuous operation.
- Optimizes the operation of the water supply system depending on its parameters by changing the upper and lower response limits.
Operating principle and design of the pressure switch
Rice. 2 Pressure switch disassembled The device is a device placed in the power supply circuit of the electric pump with the contacts closed in the normal state. It is connected to the water supply system via a fitting with an internal threaded hole. The liquid in the water line, through a hole in the fitting, presses on a round rubber membrane hidden under a metal plate. The membrane, in turn, transmits force to the bracket - a round metal button with two protruding, pointed flat protrusions along the edges, located perpendicular to the plane of the metal disk. The protrusions of the bracket when moving press on metal plate inside the case with a plastic attachment with contacts attached to it. As a result, the nozzle moves and the contact group opens.
Fig. 3 Main relay components: membrane, bracket, contact group There are two adjustment units installed under the device cover - screw racks different sizes and heights with nuts and springs underneath. The large rack sets the upper pressure limit, the small one - the range between the upper and lower response thresholds (“delta”).
Electrical wires are connected through two holes in its body to terminals located under the cover.
Connection diagram of a pressure switch to a water supply system with a submersible well pump
When connecting, the pressure switch is usually installed on the hydraulic accumulator by connecting to the terminals of the 5-inlet fitting.
Rice. 4 Water pressure switch for pump - connection diagram Connecting the pump to automation without a relay idle move is not too good option For borehole species, therefore, when installing two devices, the pressure switch is installed on a 4-inlet fitting as close as possible to the hydraulic pump.
Rice. 5 Connection diagram well pump with pressure and dry running relay
Setting up a pressure switch yourself
To connect the relay to a submersible pump, the system uses a pressure gauge to set the lower and upper thresholds for its operation. Factory pressure settings in common domestic devices (RDM-5) have a range of 1.4 - 2.8 bar.
The settings are carried out in the following sequence:
- Slightly loosen the clamping nut on the small stand, turn on the electric pump and wait for it to turn off, record the value obtained in the pressure gauge.
- Since the spring of the large strut presses on the plate, which it lifts through the bracket rubber valve, then stronger pressing of the plate by the spring increases the upper response threshold. By rotating the nut clockwise, you increase the pressure in the system or reduce it by turning the nut in the other direction. After changing the height of the pressure spring, drain the water from the system and record the new pressure with a pressure gauge. The procedure is repeated several times until the required upper limit is obtained.
- After installation upper threshold response, they begin to adjust the lower, or more precisely, the range between the relay response thresholds. By rotating the adjusting screw on a small stand, a certain spring pressure is set, they begin to drain water from the system and record the pressure gauge readings at the moment when the pump turns on. The operation is repeated several times until the desired response threshold is established, which is responsible for turning on the pump.
Rice. 6 Appearance and design of RDM-5 The pressure switch in individual water supply systems is the main and in many cases the only element of automation that controls the operation of pumping equipment. Not only the correct and reliable functioning of the water supply system, but also the performance of the electrical deep well pump. Therefore, when purchasing, you should purchase high-quality and proven devices from famous manufacturers and use reliable wiring diagrams.
Rice. 7 Example of contamination of the relay mechanism In 80% of cases, relay malfunction is caused by clogging of the input fitting and rubber membrane with sand and dirt. Therefore, installing reliable and high-quality filters into the system, especially when drawing water from sand wells, will not only improve the quality drinking water, but will also provide reliable and uninterrupted operation pumping equipment.
Autonomous water supply systems from wells and wells consist of several important nodes: pumping equipment, hydraulic accumulator, automation, pipes and equipment for water points. The pressure difference in the submersible pump raises the water by the desired height. Further through the pipes it enters storage tank, from where it is supplied to the parsing points. This ensures proper pressure and stable operation of the entire system as a whole. For normal operation water supply, it is necessary to correctly configure the automation to guarantee a minimum number of pump on/off times and extend its service life.
Scheme of an autonomous water supply system
How does a submersible pump work?
Surface and submersible pumps are used to supply water. The former are installed near water sources, and the latter are completely or partially immersed in water (the installation method depends on the design features of the particular model). The housings of submersible devices are sealed. The principle of their operation is approximately the same: the pump draws water into the housing through the inlet and pushes it through the outlet into the pipeline.
Depending on the design, the pressure difference at the inlet and outlet of a submersible pump is created either by an oscillating membrane (vibrating models) or by the rotation of one or more impellers (centrifugal devices). Many well owners install devices centrifugal type. They are more expensive, but more productive, versatile and do not destroy the casing during operation.
The duration and safety of the pump operation largely depends on automatic systems regulating the mode of their on and off. If the device is connected directly to the water supply, without a hydraulic tank, then it turns on every time the taps at the water points are opened. This mode of operation leads to its rapid failure. When connecting to a hydraulic accumulator, it is necessary to correctly set the pressure limits for the device to operate in optimal mode.
Design diagram of a centrifugal submersible pump
Pressure switch in an autonomous water supply system
For normal operation of the pump, a pressure switch is connected. This is a device that turns water-lifting equipment on and off automatically when the water pressure changes within specified limits. When the lower threshold of the specified parameters is reached, the device closes the contacts, supplies current to the pump, and it turns on. When the pressure rises to the upper threshold, the automation opens the contacts, power stops flowing to the equipment, and it turns off.
Pressure switch for the water supply system of a private house
Design features of the device
The relay design includes a flexible membrane. Under the influence of pressure in the system, it is deformed and closes or opens contacts. The operation of the device is regulated by special springs, which are adjusted using nuts - tightening or loosening them. When the nut is tightened, the spring is compressed. The tighter it is clamped, the more pressure is required to trigger it.
The difference between the thresholds for turning the device on and off is adjusted using the second nut. The more it is tightened, the greater the pressure difference. The relay is connected to the power supply network and to the pump itself using two pairs of contacts. To install the device on a water supply system pipe, a threaded hole is provided, the diameter of which is most often ¼ inch.
Submersible pump pressure switch connection diagram
Video: purpose and operating principle of a pressure switch
How to connect the device correctly
The peculiarity of connecting a pressure switch is that it has to be connected to two networks - electrical and water supply. The first stage is connecting to the water supply system. To do this, purchase a special adapter separately if the thread diameter of the water supply input differs from the threaded hole of the device.
For the pressure switch, choose a convenient location on the pipeline with free access. Threaded connections compacted with flax or other material from beginning to end. After this, the device is connected to the thread. The nut must fit exactly onto the seal. When working, you need to make sure that the sealing material does not come out or bunch up.
When the device is installed on the water supply, it is connected to the electrical network. For this purpose, one or two pairs of contacts are provided. Models with two pairs are more common on sale; home owners usually purchase them. If there are markings on the contacts, then you should follow them when connecting. If not, you need to carefully study the instructions and understand the purpose of each of the elements.
Before connecting, you must make sure that the device is in order and that the contacts open and close normally. A three-wire wire is used for connection. The first core is connected to the first contact, the second to the second, the third to the screw from the ground wire. The relay is connected to the pump contacts using a wire of the appropriate diameter.
Relay connection diagram via a five-pin fitting
Adjusting the thresholds for turning the pump on and off
The devices go on sale with factory settings. The lower threshold is usually set to turn on the pump when the pressure drops to 1.5 bar. The device turns off when the pressure reaches 2.5-3 bar. The difference (Δ - delta) is a parameter that can be adjusted with the second nut on the device. When setting, you should take into account the maximum permissible shutdown pressure. It is indicated in the technical documentation for each model and is usually 5 bar.
When adjusting the pressure limits, it is necessary to check the settings of the accumulator. Optimal pressure indicators are 1-1.5 bar. If they differ, they are corrected. After this, configure the relay:
- Open the cover to access the adjustment nuts and loosen the small pressure spring.
- The switching threshold is adjusted with a large nut. Turning clockwise increases the pressure, counterclockwise decreases it.
- Set the pressure threshold of the small spring.
Video tutorial: setting up a pressure switch for a submersible pump
When the device is connected and configured, all that remains is to check the operation of the system. To do this, open the tap, let the water drain and monitor the on-off mode of the pump. If the system operates normally, it can be put into operation. If necessary, the settings of the pressure switch of the submersible pump are adjusted.
What could be better in private system water supply? Of course, organizing it will require a lot of time, care and effort. For proper arrangement First of all, a pumping substation is needed, and in order for its operation to last for a sufficiently long period of time, it is advisable to install a water pressure switch. It can prevent overheating and, consequently, damage to the installation.
If your water supply is equipped with a water pressure sensor, you can guarantee a sufficiently long period of time without emergency operation of the water supply. The principle of operation of the protective unit is organized on a minimum and maximum pressure water at the source. If the water pressure increases, one of the springs is compressed, and when it decreases, the spring expands. Due to these manipulations performed by the springs, the contacts of the water pressure switch open, due to which the pumping station is turned off and on.
Using an example of the functionality of a water pressure switch, it looks like this: the pump begins to pump water into the storage tank (which is installed in most cases), when it is filled to its maximum, the pressure increases and the relay is activated. When the consumer turns on the water intake valve, the pressure in the hydraulic tank gradually decreases and, at a minimum value, the relay starts the pump again. This process is repeated in a circle. Watch the video material for our article.
How to adjust the pressure sensor for the pump?
The most important process in the arrangement private well- this is the adjustment of the pressure switch of the pumping station. The important thing here is to use correct principle. This question can take a lot of time, so you need to follow a clear algorithm.
Important! In addition to a single check, you will have to regularly measure the pressure in the hydraulic tank approximately once every 30 days.
- When the normal operating mode is selected, it should be adjusted using the regulator. If you are not satisfied with any pressure indicator, you can bleed it or pump it up. The recommended value is at least 1 atmosphere in the hydraulic accumulator.
- If you independently assembled the pump in the water supply system, adjusting the pressure switch must be carried out without fail. To begin with, the small nut and the maximum pressure value are adjusted. Make sure that this value is not higher than the factory standard, since in such situations it is necessary to manually turn off the pump.
- Next, the pressure switch of the pumping station is set to the minimum value using a large nut in the pressure switch for the pump. This can be achieved by draining water from the accumulator. In this case, a pressure gauge must be installed in it. At the moment when the arrow on the scale shows the minimum value, the pump should turn on. Automation is adjusted according to meter readings.
Important! Remember that it is better to adjust the lower pressure so that it is 10% greater than the air pressure in the tank. Otherwise, this is fraught with rapid wear of the rubber membrane.
- In some cases, it is permissible to set pressure limits according to your own preference. It should be remembered that the reference point should be the large nut, that is, the lower pressure limit. The upper limit can only be that for which the entire pumping system is designed. It is also possible to use a pm 5 pressure switch.
We draw the attention of the consumer that the regulator must be selected depending on the conditions of your water supply and technical specifications well pump. The connection diagram of the pressure switch must be used in the work.
Automatic home pump equipment
The automation involved in the equipment of modern pumps most often consists of several devices. Let's look at what these devices are below:
You may encounter a situation where the settings have gone wrong or the pressure switch has failed. This is easy to notice: either the pressure in the water supply has decreased, or the pumping station does not turn on at the given lower pressure limit.
A mechanical pressure switch automates the operation of the pumping station, controlling the pump on and off to maintain stable water pressure in the pipeline. The standard settings are set at the manufacturer: cut-off pressure 2.5 - 3.0 atm., turn-on pressure - 1.5 - 1.8 atmospheres (depending on the manufacturer). If problems are noticed with water pressure in the house, it is necessary to responsibly approach the setting of the pressure switch, since there is a direct relationship between the relay setting, the volume of the accumulator and the pressure.
Setting up a pressure switch begins with checking the pressure compressed air in the hydraulic accumulator. In this case, the pumping station should be disconnected from the network and the accumulator tank should be empty. To do this, unscrew the side cover on the tank (see figure - red arrow) and using a normal car pump Check the pressure with a pressure gauge. It should be about 1.5 atm. If the measured value is less, the pressure must be raised by the pump to the required level. It should be noted that the air in the tank must always be under pressure, and when operating the pumping station it must be checked from time to time and pumped up if necessary, which will increase the service life of the accumulator membrane.
If, after adjusting the pressure in the accumulator, the pumping station does not operate normally, you need to start setting up the pressure switch itself. It should be remembered that the pump shutdown pressure ( top setting) must not exceed the pressure that the pump is capable of developing!
Setting up the pressure switch RDM-5 of the pumping station
The RDM-5 pressure switch is adjusted in a working system under pressure. To do this, we turn on the pumping station to the network and let the pump raise the pressure in the system, after which the relay will operate and the engine will turn off.
- Remove the relay cover and completely loosen the clamping nut of the smaller spring.
- We set the required minimum pressure (turn on the pump). To do this, rotate the clamping nut of the larger spring (clockwise - increase the pressure and vice versa). Then we open the tap and let the water drain, which reduces the pressure in the system. We watch when the pump turns on and, if the result is not satisfactory, we adjust further until we achieve the required result.
- We adjust the pump shutdown pressure (upper limit). By rotating the clamping nut of the smaller spring, we set the required value of the upper pressure. We proceed as follows. We turn on the pump and wait for the relay to operate. If the shutdown pressure is not satisfactory, drain the water, adjust the spring and repeat the process.
Thus, we configured the pressure switch.
Repair of pump station pressure switch (video)
What do you want if the relay is not adjustable? It's probably malfunctioning. There are two ways to solve this problem: buying a new relay or repairing the existing one. In the first case, we advise you to take a closer look at modern and inexpensive pressure switches - pointer or digital.
For those who do not yet want, for one reason or another, to change an already obsolete relay, we recommend using the methods.
You will find a detailed repair procedure in this video:
Complete with the pumping station, the owner of the house or cottage receives a water pressure switch for the pump. It allows you to fill the hydraulic tank automatically, saving owners from unnecessary hassle, but requires the most careful attention. The fact is that this key must, firstly, be connected correctly, and secondly, adjustments must be made to suit the needs of a particular home and its plumbing system. Neglect these important points can lead to breakdown of the entire pumping station, as well as to a reduction in its service life. Before connecting and setting up the equipment, you need to understand the operating principles of the device and the hydraulic accumulator.
Purpose, device and principle of operation
A relay is the main element for regulating the water supply to pumping system. Thanks to it, the entire pumping equipment system is turned on and off.
It is this node in the water supply system that is responsible for the water pressure. Thanks to the relay, there is a balance between high supply and weak supply.
The relay is designed on the principle of opening the contact group when the water pressure changes. It is directly connected to the pump using output contacts. The diagram below shows the main components of the water pressure switch device.
Water pressure switch diagram
Two network contacts serve to electrically start the device. Using the pump contact group, the relay is switched on and off. There are two nuts on the top of the device. They are designed to regulate the pressure supply. Each nut is responsible for the force of water pressure in the system. When adjusting the relay, you should always remember that the device should turn off at an average water supply pressure in the pump. The differential adjustment nut adjusts the water supply between high and low pressure.
Using a relay, the switching on and off of the device supplying water to the hydraulic tank is automatically controlled. In this case, experts use a number of concepts, such as:
- Turn-on pressure or lower pressure (Rvkl), at which the relay contacts for a submersible or well pump close, the device turns on and water begins to flow into the tank. The manufacturer's standard setting is 1.5 bar.
- Switch-off pressure or lower pressure (Poff), at which the device contacts open and the pump turns off. The manufacturer's standard settings are 2.5-3 bar.
- Pressure drop (ΔP) is the difference between the previous two indicators.
- The maximum permissible shutdown rate at which the pumping station can be turned off. The manufacturer's standard settings are 5 bar.
The hydraulic accumulator is a tank in which an additional rubber container called a “bulb” is built in. A certain amount of air is pumped into this “pear” through the most ordinary car nipple. The higher the pressure in the bulb, the more it puts pressure on the water accumulated in the tank, pushing it into the plumbing system. This ensures sufficient water pressure for comfortable use.
Membrane accumulators are designed somewhat differently, but their operating principle is approximately the same. The tank is divided into two parts by a special membrane, on one side of which there is water, on the other there is air that presses on the water, etc.
Relay classification
There are two types of relays based on the principle of operation - mechanical and automatic. When purchasing this mechanism, you need to consider what functions this device should perform.
In addition, automatic relays, although easier to operate, are less durable than mechanical ones. Therefore, most buyers opt for the mechanical option.
In addition, relays are sold either built into the pumping station or separately from it. Therefore, you can select a relay based on individual characteristics that will improve the operation of all equipment.
Mechanical type
- Mechanical pressure switch SQUARE with dry running protection. The pressure generated by this device ranges from 1.3 to 5 bar. Required current for efficient work the relay is 10 A.
- Pressure switch Cristal. Current required for operation of this device, 16 A. The permissible pressure limit in the water supply system is 4.5 bar.
Electronic
Electronic relays are more susceptible to breakdowns due to the fact that when water is supplied, various small particles appear in it, which damage the equipment. To prevent this from happening, a special filter is placed at the supply inlet, which purifies the water and does not prevent damage to the device. Electronic device It is better than a mechanical one in that it does not allow the pumping station to run idle.
After pressing the button to turn off the water supply, the electronic relays operate for another 16 seconds. This function is necessary to ensure that the device operates for a longer time.
An electronic relay is easier to install and configure. To reconfigure its operation, the entire system does not need to be disassembled; you just need to configure the necessary parameters on the electronic display using the appropriate buttons.
- Pressure switch PS-15A with dry running. This electronic device operates in a pressure range from 1 to 5 bar. The current is 12 A. In addition to the listed characteristics, the device has built-in factory settings and full protection against dry running.
- Pressure switch PS-2-15. Has factory settings and dry-running protection. The possible pressure limit in the water supply system is 5.6 bar, the current is 10 A.
Installation and connection of the relay: instructions
To install the relay, you must first make mechanical assembly the entire system, then you should connect these devices to the electrical network.
Electrical part
According to this diagram, connect to terminals L1 and L2 electric wires to the general network. Connect the pump terminals to the M terminals, and connect the ground to the corresponding terminals.
The wires must be connected to special terminals
Then carry out the work according to the connection diagram presented below for the electrical and mechanical parts of this connection.
After connecting the mechanical part, you need to connect the electrical part.
But such a connection system does not save the pumping station from dry running. Therefore, the pump should be installed in correct position, i.e. an order of magnitude higher than the located check valve.
A system connected according to this principle will operate in protected mode
This is a slightly different option for installing a home unit. But if the entire installation is carried out in accordance with this scheme, the pump will operate in a protected mode, that is, the mode of operation of the pump without water supply will be excluded.
This principle of operation of the pumping station will save the entire water supply system from rapid wear and complete failure.
All rules and instructions for connecting pumping equipment must be followed. First of all, you need to determine the required water pressure and select a relay based on this indicator.
- A cable with a solid conductor cross-section of at least 2.5 square meters is suitable from the shield. mm or PVA 3x1.5. The parameters depend on the characteristics of the pump and can be selected based on current.
The pressure switch is connected to two systems: electrical and mechanical
- Lead the wires into special inputs on back side housings. Inside there is a terminal block with contacts: grounding - conductors from the panel and pump are connected; line terminals - the phase and neutral wires from the panel are connected to them; terminals for the same wires from the pump.
There is a terminal block inside
- Connect the wires and secure them in the terminals.
Press the wires into the terminals
- Close the relay cover. Installation is complete, make adjustments if necessary.
Close the relay with a cover and secure with bolts
Video: how to install a pressure controller
Checking the pressure in the water supply system using a pressure gauge
Immediately after purchasing a pumping station, you need to check the indicators that are set in the hydraulic tank by the manufacturer. Typically this figure is 1.5 atmospheres. However, during storage and transportation, leakage of some air from the tank is a completely common occurrence.
For checking, it is recommended to use a car pressure gauge with the least graduated scale possible to ensure accurate measurement. Some models pumping stations are equipped with plastic pressure gauges, but practice has shown that they are unreliable and do not provide accurate pressure readings in the hydraulic tank. Another option is electronic pressure gauges, the readings of which largely depend on the battery charge level and the ambient temperature. Considering the high cost of electronic pressure gauges and the extreme unreliability of Chinese plastic products, experts recommend choosing a regular mechanical automobile pressure gauge, enclosed in a metal case.
To set the pump pressure switch, it is best to use a mechanical pressure gauge
To check the pressure in the accumulator, you need to remove the decorative cap under which the nipple is hidden, connect a pressure gauge to it and take readings. The lower the pressure, the greater the supply of water that can be created in it. To create a sufficiently large water pressure, a pressure of 1.5 atm is considered an acceptable indicator. But the atmosphere alone is quite enough to provide the household needs of a small house.
At high blood pressure the pump turns on more often, which means it wears out faster, but the water pressure in the system is created approximately the same as in a city water supply system. This allows, for example, the use of a hydromassage shower. At low pressure the pump wears less, but maximum comfort, which you can afford - an ordinary bathtub filled with hot water, but not the charms of a jacuzzi.
Please note that experts do not recommend over-pumping the hydraulic tank or reducing the pressure to less than one atmosphere. This can lead to an insufficient supply of water in the accumulator, or damage to the rubber bulb.
After these nuances have been clarified, air is either pumped into the hydraulic tank or vented until the required level is reached.
How to adjust correctly (with hydraulic accumulator)
Before setting the relay, you need to remove the cover, under which there are two springs with nuts: large and small. By turning the large nut, the lower pressure in the hydraulic accumulator (P) is adjusted. By rotating the small nut, the pressure difference (ΔР) is set. The starting point is the position of the large spring, with the help of which the lower pressure limit is set.
Before you begin setting up the pressure switch for the pump, you must remove the top cover from the device, which hides the large and small springs
After the accumulator has reached required parameter air, the tank should be connected to the system and turned on, observing the readings of the water pressure gauge. Note that the technical documentation for each pump indicates operating and maximum pressure indicators, as well as permissible norm water consumption. These values must not be exceeded when configuring the relay. If during system operation the operating pressure accumulator or pump limit value, you must turn off the pump manually. The maximum pressure is considered reached at the moment when the pressure stops increasing.
Fortunately, regular household pump models are not powerful enough to pump the tank to its maximum capacity. Most often, the difference between the set on and off pressures is 1-2 atmospheres, which fully ensures optimal use of the equipment.
Once the water pressure gauge shows the required lower pressure, the pump should be turned off. Further adjustment is made as follows:
- Carefully rotate the small nut (ΔP) until the mechanism starts to work.
- Open the water to completely empty the system of water.
- When the relay turns on, the lower value will be reached. Please note that the pump activation pressure should be approximately 0.1-0.3 atmospheres higher than the pressure reading in an empty hydraulic tank. This will protect the “pear” from premature damage.
- Now you need to rotate the large nut (P) to set the lower pressure limit.
- After this, the pump is turned on again and waited until the indicator in the system rises to the desired level.
- All that remains is to adjust the small nut (ΔP), after which the hydraulic accumulator can be considered adjusted.
Adjustment diagram
Here is a diagram that is suitable for most devices:
The pressure switch for the pump is adjusted using two nuts: large and small. They must be handled very carefully so as not to damage the device.
Video: how to adjust the relay for the pump
In addition to the initial setup when connecting the relay to the pump, the home owner needs to periodically check the operation of the system and adjust the settings. At least once every three months, experts recommend completely draining the water from the hydraulic tank and checking the air pressure by pumping up required amount or bleeding off excess.
