Water flow switch: device, principle of operation + instructions for connecting

Taking good care of the equipment that supplies water significantly extends its service life and guarantees uninterrupted operation of the system. This requires not only timely inspection and proper care, but also equipping the pumps with a full set of protection devices. Preventing the possibility of a serious breakdown is much cheaper than repairing or buying a new unit. Do you agree?

Installing a water flow switch will protect the motor of both surface and deep-well pumping equipment. After all, most often when the motor burns out, it is easier to buy a new pump than to change it. We will tell you how this important protective device works, how to choose it and include it in an autonomous water supply.

The article provides valuable recommendations for installing devices to protect pumps from operating in “dry running” conditions. The technology of customization for individual requirements has been analyzed. For a better understanding of the considerable amount of information, photographs, diagrams, video reviews and manuals are attached.

Functional purpose of the flow switch

In household water supply systems, the action of a pumping station without water quite often occurs and threatens an accident. This problem is called “dry running”.

As a rule, the liquid cools and lubricates the elements of the system, thereby ensuring its normal operation. Even short-term dry operation leads to deformation of individual parts, overheating and failure of the equipment motor. Negative consequences apply to both surface and deep-well pump models.

Dry running occurs for various reasons:

• incorrect choice of pump capacity;
• unsuccessful installation;
• violation of the integrity of the water pipe;
• low fluid pressure and lack of control over its level, for which a pressure switch is used;
• accumulated debris in the pumping pipe.

An automatic sensor is necessary in order to completely protect the device from the threats posed by a lack of water. It measures, controls and maintains constant water flow parameters.

Pumping equipment equipped with a sensor has many advantages. It lasts longer, breaks down less often, and uses energy more economically. There are also relay models for boilers

The main purpose of the relay is to independently turn off the pumping station when the liquid flow is insufficient and turn it on after normalization of the indicators.

DIY water flow switch - Safety Portal

Taking good care of the equipment that supplies water significantly extends its service life and guarantees uninterrupted operation of the system. This requires not only timely inspection and proper care, but also equipping the pumps with a full set of protection devices. Preventing the possibility of a serious breakdown is much cheaper than repairing or buying a new unit. Do you agree?

Installing a water flow switch will protect the motor of both surface and deep-well pumping equipment. After all, most often when the motor burns out, it is easier to buy a new pump than to change it. We will tell you how this important protective device works, how to choose it and include it in an autonomous water supply.

The article provides valuable recommendations for installing devices to protect pumps from operating in “dry running” conditions. The technology of customization for individual requirements has been analyzed. For a better understanding of the considerable amount of information, photographs, diagrams, video reviews and manuals are attached.

Design and operating principle

The sensor has a unique device, thanks to which it performs its direct functions. The most common modification is the paddle relay.

The classic building scheme includes the following important elements:

• an inlet pipe that passes water through the device;
• valve (petal) located on the wall of the inner chamber;
• an isolated reed switch that opens and closes the power supply circuit;
• springs of a certain diameter with varying degrees of compression.

While the chamber is filled with liquid, the force of the flow begins to act on the valve, moving it around its axis.

A magnet built into the back of the petal comes close to the reed switch. As a result, the contacts close, turning on the pump.

The flow of water is understood as the speed of its physical movement sufficient to turn on the relay. Reducing the speed to zero, resulting in a complete stop, returns the switch to its original position. When setting the response threshold, this parameter is set taking into account the conditions of use of the device

When the flow of fluid stops and the pressure in the system drops below normal, the compression of the spring weakens, returning the valve to its original position. Moving away, the magnetic element ceases to operate, the contacts open and the pumping station stops.

Some modifications are equipped with a return magnet instead of springs. Judging by user reviews, they are less susceptible to minor pressure surges in the system.

Petal relays have a large number of advantages. Among them are a simple and unpretentious design, instant response, no delays between repeated responses, and the use of a precise trigger to start the equipment.

Depending on the design solution, several more types of relays are distinguished. These include rotary devices equipped with a paddle wheel rotating in a water flow. The speed of rotation of the blade in them is controlled by touch sensors. If there is liquid in the pipe, the mechanism deflects, closing the contacts.

There is also a thermal relay that operates according to thermodynamic principles. The device compares the temperature set on the sensors with the temperature of the working medium in the system.

If there is flow, a thermal change is detected, after which the electrical contacts are connected to the pump. If there is no water movement, the microswitch disconnects the contacts. Thermal relay models are characterized by high sensitivity, but they are quite expensive.

Device selection criteria

When choosing equipment that controls the force of water flow, you should carefully study its technical characteristics.

Particular attention should be paid to the operating temperature and pressure range for which it is designed, the diameter of the threads and mounting holes, the protection class, and application nuances. It is also important to clarify what materials the product is made from.

Experts consider devices made of brass, stainless steel, and aluminum to be the most reliable and durable. These materials protect the structure from the critical consequences of a common phenomenon in water supply systems - water hammer.

When considering different modifications of the relay, it makes sense to purchase a version made of metal. The housing and working components of such devices are highly durable.

This fact allows the equipment to withstand serious loads for a long time that arise due to significant pressure in the water supply from the liquid passing through the sensor.

The pressure value at which the relay operates must correspond to the power of the installed pump. The parameters of the water flow circulating through the pipeline depend on this characteristic.

It is advisable to choose a device with two springs that controls the operation of the pumping station according to certain lower and upper pressure marks.

The operating temperature range of the sensor directly indicates its possible area of ​​application. For example, models with a high limit temperature are designed for hot water supply circuits and heating systems. For cold water pipelines, a range of up to 60 degrees is sufficient

Another important criterion that deserves special mention is the climatic conditions necessary for the operation of the product. This refers to the recommended air temperature and humidity level that the device needs to provide in order for it to perform at its best.

The maximum permissible load for a particular device is determined by the protection class specified in the technical specifications.

When purchasing a flow sensor, you should check the thread diameter and the dimensions of the mounting holes in the equipment: they must fit perfectly with the pipeline elements. The correctness and accuracy of further installation, as well as the efficiency of the relay after installation, depend on this.

Water flow switch for pump: characteristics, principle of operation, installation

Ensuring the efficient operation of pumping units is the key to the uninterrupted functioning of the water supply and heating systems they serve. To solve such an important task, pipelines are equipped with additional technical devices, one of which is a water flow sensor (or water flow sensor). Its use makes it possible to control failures that may periodically occur in pipeline systems and, accordingly, minimize the risk of failure of pumping equipment.

Lobe flow sensors, non-adjustable

Purpose and benefits

When operating domestic water supply systems, there are often situations when the pump turns on when there is no liquid in the pipes.

Such situations, if they occur frequently and continue for a long time, cause overheating of the pump motor and deformation of its parts, which ultimately leads to failure of the entire device.

The water pumped by pumping equipment simultaneously performs lubricating and cooling functions, so “dry running,” as it is also called, negatively affects the technical condition of both circulation and submersible pumps.

In order to prevent the occurrence of the described situations, they use a water flow sensor for the pump, operating in automatic mode. Sensors that monitor water flow are successfully used to control the operation of pumping stations serving hot and cold water supply systems, as well as heating systems.

Sensor location diagram in the water supply system

The automatic device in question monitors the parameters of the flow of water that passes through it, and in cases where they differ from the standard ones, it automatically turns on or off the pumping equipment. Working on this principle, the sensor not only protects pumping equipment from “dry running”, but also ensures constant water flow parameters.

Among the advantages of operating pumping equipment on which a fluid flow sensor is installed are:

• reducing energy consumption and, accordingly, reducing the cost of paying for it;
• minimizing the risk of failure of pumping equipment;
• increasing the service life of pumping equipment.

Design features

The main tasks that water flow control sensors installed in domestic pipelines solve are to turn off pumping equipment at a time when there is no liquid in the system or its flow pressure exceeds the standard value, and turn it on again when the pressure drops. An effective solution to these important problems is provided by the sensor design, which consists of the following elements:

• a pipe through which water enters the sensor;
• a membrane that makes up one of the walls of the inner chamber of the sensor;
• a reed switch that provides closing and opening of the pump power supply circuit;
• two springs of different diameters (the degree of their compression regulates the pressure of the fluid flow, at which the water flow switch for the pump will operate).

Main components of an industrial flow sensor

The device of the above-described design works as follows:

• Entering the inner chamber of the sensor, the water flow puts pressure on the membrane, displacing it.
• The magnetic element fixed on the back side of the membrane, when it is displaced, approaches the reed switch, which leads to the closure of its contacts and the pump being turned on.
• If the pressure of the water flow passing through the sensor drops, the membrane returns to its original position, the magnet moves away from the switch, its contacts open, and accordingly, the pumping unit is turned off.

The operating principle of a flow sensor based on a permanent magnet and a reed switch

Sensors that monitor water flow are installed quite simply in pipeline systems for various purposes. The main thing is to choose the right device, paying attention to its operating parameters and characteristics of the pumping equipment.

Main characteristics

When choosing water flow sensors to equip a pipeline system, the following parameters must be taken into account:

• material for manufacturing the body and internal elements;
• operating pressure for which the sensor is designed;
• temperature range of the liquid to control the flow of which the device will be used;
• protection class and requirements for operating conditions;
• diameter of mounting holes and thread parameters in them.

Each of the above parameters affects the operational features of water flow sensors, so it is worth considering them in more detail.

The reliability of such a device, its ability to withstand loads arising during operation, as well as its durability depend on the material from which the sensor body and its internal parts are made. When choosing a fluid flow sensor, it is better to give preference to models for the manufacture of which various metals were used - stainless steel, brass or aluminum.

During operation, both the body of the flow sensor and its internal elements experience significant pressure from the liquid passing through it. Only durable materials can withstand such a load for a long time.

In addition, phenomena such as water hammer are common in pipelines, the consequences of which can quickly damage the sensor if inappropriate materials were used for its manufacture.

Flow sensor with brass body

The operating pressure at which the fluid flow sensor can operate correlates with the power of the pump used, so special attention should be paid to this parameter. In addition, this parameter also determines what characteristics the liquid flow transported through the pipeline will have. Those models of water flow sensors, which are designed with two springs, can control the operation of the pump at the lower and upper pressure levels. It is better to give preference to devices of this particular type.

The temperature of the liquid for which the sensor is designed has a direct impact on the systems in which it can be used. Naturally, when choosing such a sensor to equip a heating or hot water supply system, you should pay attention only to those models that can work with water heated to a high temperature. For pipelines through which cold water is transported, flow sensors are used, designed to work with liquids having a temperature of 60–80°.

Boost pump with flow sensor

The level of humidity and ambient temperature at which the fluid flow sensor can be operated are also important parameters. The protection class of such a device indicates what loads it can withstand when working in tandem with pumping equipment.

Sensors that monitor water flow are usually chosen for ready-made pipeline systems or for those whose design has already been developed. That is why you should pay attention to the dimensions of the mounting holes: they must fully correspond to the dimensions of the pipeline elements on which the sensor is planned to be installed.

Trusted Instruments

Among the entire range of relays, the two models that are in approximately the same price category are in greatest demand - about $30. Let's take a closer look at their characteristics.

Genyo Lowara Genyo 8A

Development of a Polish company engaged in the production of electronic equipment for control systems. Designed for use in domestic water supply systems.

Genyo allows automatic pump control: starting and shutting down based on actual water consumption, preventing any pressure fluctuations during operation. Also, the electric pump is protected from running “dry”

The main purpose is to control the pump and control the pressure in the pipes during operation. This sensor starts the pump when the water flow exceeds 1.6 liters per minute. It consumes 2.4 kW of electricity. Operating temperature range – from 5 to 60 degrees.

Grundfos UPA 120

Manufactured in factories in Romania and China. Maintains stable water supply in premises equipped with individual water supply systems. Prevents pumping units from idling.

The Grundfos brand relay is equipped with a high protection class, allowing it to withstand almost any load. Its electricity consumption is about 2.2 kW

The device’s automation starts at a liquid flow rate of 1.5 liters in one minute. The limit parameter of the temperature range covered is 60 degrees. The unit is manufactured in compact linear dimensions, which greatly facilitates the installation process.

Recommendations for installation and configuration

Liquid flow relays are installed for devices that require constant control and compliance with a certain operating mode. Often they are equipped with equipment at the production stage. However, there are also circumstances when a separate installation of the sensor is required.

Rules for installing relays in the system

Installing a safety device that detects the presence or absence of water flow in the system is a reasonable step in cases where it is not possible to be present while the pumping equipment is operating.

It is not required only in two cases:

1. Water is pumped from a large well with unlimited resources by a low-power pump.
2. It is possible to independently turn off the installation when the water level drops below the designated norm.

The device is installed on horizontal sections of the pipeline. In this case, you need to ensure that the membrane assumes a stable vertical position.

The device is mounted to the drain pipeline using a threaded coupling. Usually a special socket is provided for this.

If the pumping equipment does not have a hole for mounting the sensor, you can replace it with a brass tee. In addition to the relay, a pressure gauge is connected to it, showing the current pressure in the network

Before you start directly screwing the device, it is advisable to seal the threads well with flax or thread, sold in specialized departments.

It is better to wind it clockwise towards the end. This method of fastening increases the reliability of fixation.

In order not to damage the relay, you should screw it in very carefully, slightly tightening it with a wrench. The optimal distance between the product and the pipeline is at least 55 mm

When installing a factory sensor, you need to focus on the arrow shown on the body. The direction indicated on it must coincide with the direction of flow of the liquid passing through the device.

If contaminated water is transported through the pipeline, it is recommended to install cleaning filters, placing them near the sensor. Such a move will ensure the correct operation of the product.

At the final stage of installation work, the dry-running relay is connected to the electrical network:

• a wire core is screwed to the free ends of the two groups of contacts;
• a ground connection is attached to the sensor screw;
• the device is connected to the pump by connecting two devices with a regular wire, matching the colors of the cores.

After connecting to the network, all that remains is to check the functionality of the system. The fact that the device is ready for full operation will be indicated by an increase in pressure marks on the pressure gauge and the automatic shutdown of the pump when the limit value is exceeded.

Self-adjustment procedure

For adjustment, the sensor has special bolts. By loosening or tightening them, you can reduce or increase the compression force of the spring.

This sets the pressure level at which the device will operate.

Almost always, manufacturing companies produce equipment with adjusted settings. Despite this, sometimes additional self-adjustment is required

In most cases, setting up automatic equipment is not difficult.

It is advisable to adhere to the following algorithm:

• drain the liquid from the system until the pressure mark reaches zero;
• turn on the pumping unit and slowly let the water back in;
• record the flow pressure indicator when the pump is turned off with a sensor;
• start draining again and remember the indicators at which the pumping equipment will start working;
• open the relay and use the adjusting bolt to set the minimum level of compression of the larger spring required to activate the device and start the pump (more compression increases the degree of pressure, less - reduces it);
• in a similar way, adjust the compression force of a smaller spring mechanism, setting the limits of the maximum pressure, upon reaching which the relay measuring the water flow will turn off the pump.

Having completed all the described manipulations, you should make sure that the adjustments made are correct. To do this, the pipeline is filled with liquid and then drained, assessing the sensor’s response when the set values ​​are reached.

If the test result is unsatisfactory, the procedure is repeated.

Having insufficient experience and qualifications, it is better to seek help in adjustment from specialists. They will analyze the specific situation, take into account the technical characteristics of the equipment and select the most correct pressure level values

To ensure that the pipeline through which the liquid passes works properly and stably, regular annual checks of the flow sensors are carried out. If necessary, the operating parameters are adjusted.

Water pressure switch: how to choose, configure it yourself

To control pumps, stations and other water supply devices, it is necessary to use special devices. A differential water pressure switch for the pump allows you to automatically turn off or turn on the pump when the pressure in the system changes.

Setup and installation

Before configuring the system, you must install the sensor. Electrical diagram for connecting the water pressure switch:

1. The sensor is installed directly on the outlet pipe. It is connected to the pipes using a fitting. Two holes are allocated for the hot and cold pipes, one for the hydraulic accumulator, and the remaining two for the pressure gauge and relay;
2. When screwing on a fitting, a special plumbing tape must be used;
3. Any level and pressure sensor has two terminals for electrical wires. From one contact the cable is fed to a pump or boiler, from the other to a source of electricity; Photo - five-way fitting
4. For installation, the cable must be stripped and installed on the terminals. After completing the installation work, the water pressure switch is adjusted.

To adjust the water level pressure switch in the water supply system with your own hands, you just need to change the limits of its operation. This process is called thoriation.

Photo - sensor and components

Step-by-step instructions on how to set up a water pressure switch:

1. First, remove the cover of the device. To do this, unscrew the screws on its surface;
2. Visually, the springs can be distinguished due to the visible difference in size: the differential one has a larger diameter, and the minimum pressure, accordingly, has a smaller one;
3. The upper one is pulled up to adjust the level of high (maximum) pressure in the system, and the lower one – to adjust the minimum;
4. After adjustments are made, the cover is put in place. The nuts are tightened, but be careful not to overtighten them.

It is worth noting that if the minimum trigger level is incorrectly set, a dry running problem may occur. This is the main reason for the malfunction of the pump, boiler or other devices.

It occurs when a device with high efficiency (higher than necessary) is used to supply water. Experts also say that another reason for dry running is the emptying of the storage tank. This problem often occurs in a domestic hot water supply system (when pumping hot water through pipes, the pump eventually completely empties the tank). The water pressure in the system does not change, but then the pump and relay operate “idle”.

Photo - relay on the boiler

To avoid this problem, you need to choose a special water pressure switch or supplement the existing one with certain devices:

1. Buy a device that uses dry-running protection. These devices cost a little more than conventional ones, but are more effective. Their main difference is the ability to respond to a drop in pressure below 0.4 bar (these are Danfoss models - Danfoss, relay 0.2-1.2 bar XP600 Ariston);
2. Installation of a special press control instead of the sensor. This is a special type of controller that not only controls the pressure, but also allows you to turn on the pump even if it drops below a predetermined minimum level. If there is no water in the system, the pressure drops very quickly and many devices simply do not have time to react to this. Even though the pump turns on after a short period of time, it still operates in the specified mode.

It should be noted that if repair or complete replacement of the sensor is required, it is completely removed from the pipeline. It won't be possible to fix it on the spot. For preventive maintenance, the device is disconnected from the water supply and electricity systems.

: irrigation pump pressure switch https://www..com/watch?v=y4RwGLPwliM

Price overview

Let's look at where you can buy a Grundfos MDR 21/6 water pressure control relay and what its price is in different cities of Russia:

Source: https://www.asutpp.ru/rele-davleniya-vody.html