Water flow switch: device, principle of operation + instruction on connection

Careful attitude to the technology that provides water, significantly extends its working life, ensures uninterrupted operation of the system. This requires not only timely inspection and proper care, but also the equipment of the pumps with a complete set of protection devices. Preventing the likelihood of serious damage is much cheaper than repairing or buying a new unit. Do you agree?

Installing a water flow switch will protect the motor from both surface and submersible pumping equipment. After all, most often when a 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 turn it into an independent water supply system.

The article provides valuable recommendations on the installation of pump protection devices against operating in the “dry run” condition.Disassembled technology settings for individual requirements. For a better perception of a considerable amount of information, photographs, diagrams, video reviews and manuals are attached.

Functional purpose of the flow switch

In domestic water pipelines, an accidental action of a pumping station without water often happens. This problem is called the “dry run”.

As a rule, the liquid cools and lubricates the elements of the system, thereby ensuring its normal performance. Even a short dry run leads to deformation of individual parts, overheating and failure of the engine equipment.

Negative effects relate to both surface and deep pump models. Dry running occurs for various reasons:

  • wrong choice of pump performance;
  • bad installation;
  • violation of the integrity of the water pipe;
  • low fluid pressure and lack of control over its level;
  • accumulated debris in the pumping pipe.

An automatic sensor is needed in order to completely protect the device from the threats posed by water scarcity. It measures, controls and maintains the constancy of the parameters of the water flow.

Pump equipped with a flow sensor
Pumping equipment equipped with a sensor has many advantages. It serves longer, fails less often, and uses energy more economically. There are also models of relays for boilers.

The main purpose of the relay is to turn off the pumping station on its own in the event of insufficient power of the fluid flow and switching on after normalization of the parameters.

Design and principle of operation

The sensor has a unique device, thanks to which it performs its direct functions.

The most common modification is the petal relay. The classical scheme of the structure includes the following important elements:

  • water inlet through the device;
  • a valve (petal) located on the wall of the inner chamber;
  • insulated reed switch, closing and opening the power supply circuit;
  • springs of a certain diameter with different degrees of compression.

At a time when the chamber is filled with fluid, the flow force begins to act on the valve, displacing it around the axis.

The magnet embedded on the back side of the petal is very close to the reed switch.As a result, the contacts are closed, including the pump.

Water flow pressure
Under the flow of water understand the speed of its physical movement, sufficient to turn on the relay. Reducing the speed to zero, leading to a complete stop, returns the switch to its original position. When setting the threshold, this parameter is set according to the conditions of use of the device.

When fluid flow ceases 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 function, the contacts open and the pumping station stops.

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

Diagram of the device of the petal relay
The petal relay is characterized by a large number of advantages. Among them - a simple and unpretentious design, instant operation, no delays between the repeated response, the use of an exact trigger to start the equipment

Depending on the design, several other types of relays are distinguished.These include rotary devices, equipped with a paddle wheel rotating in a water stream. The speed of rotation of the blade in them is controlled by sensor sensors. If there is fluid in the pipe, the mechanism is deflected, closing the contacts.

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

In the presence of flow, a thermal change is recorded, after which the electrical contacts of the power grid are connected to the pump. In the absence of water movement, the microswitch disconnects the contacts. The thermal relay is characterized by high sensitivity, but they are quite expensive.

Instrument Selection Criteria

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

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

Quality Metal Sensor
The most reliable and durable experts believe devices made of brass, stainless steel, aluminum.These materials protect the structure from the critical effects of a frequent phenomenon in water supply systems - water hammering.

Considering various modifications of the relay, it makes sense to purchase a version made of metal. The housing and working components of such devices are characterized by increased strength.

This fact allows the equipment for a long time to withstand serious loads arising due to significant pressure from the fluid passing through the sensor.

The value of pressure at which the relay operates must correspond to the capacity 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.

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

Another important criterion worth mentioning is the climatic conditions necessary for the operation of the product. We are talking about the recommended air temperature and the level of humidity that the device needs to provide so that it can work with the best performance.

The maximum permissible loads for a specific device are determined by the protection class specified in the technical specifications.

When buying a flow sensor, check the diameter of the thread section and the dimensions of the mounting holes in the equipment: they should fit perfectly with the pipeline elements. From this depends on the accuracy and accuracy of further installation, as well as the effectiveness of the relay after installation.

Credible appliances

Among the entire range of relays, two models are in the greatest demand, being approximately in the same price category - about $ 30. Consider their characteristics in more detail.

Genyo Lowara Genyo 8A

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

Genyo - Lowara Genyo 8A
Genyo enables automatic pump control: start and shutdown based on actual water consumption, preventing any pressure fluctuations during operation. Also, the electric pump is protected from work "dry"

The main goal 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. The operating temperature range is from 5 to 60 degrees.

Grundfos UPA 120

Manufactured in factories in Romania and China. It maintains the stability of the water supply in rooms equipped with individual water supply systems. Prevents pumping operation at idle.

Grundfos UPA 120 Sensor Model
Relay brand Grundfos is equipped with a high class of protection, allowing him to endure almost any load. Electricity consumption in it is about 2.2 kW

Automatic device starts at a flow rate of 1.5 liters per minute. The boundary parameter of the temperature range covered is 60 degrees. The unit is produced in a compact linear dimensions, greatly facilitating the installation process.

Recommendations for installation and configuration

Relay fluid flow set for devices that need constant control and compliance with a certain operating mode. Often they are equipped with equipment at the production stage. However, there are also such circumstances when you need a separate sensor installation.

Rules for installing relays in the system

Installing a safety device that determines the presence or absence of water flow in the system is a reasonable step in cases where it is not possible to be present at all times during the operation of the pumping equipment.

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 turn off the installation independently when the water level drops below the indicated rate.

The device is installed on horizontal sections of the pipeline. At the same time, it is necessary to ensure that the membrane adopts a stable vertical position.

The fixture is mounted to the drain pipe with a threaded coupling. Usually a special socket is provided for this.

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

Before proceeding with the direct screwing of the device, it is advisable to seal the thread well with flax or thread sold in specialized departments.

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

Installation of the sensor to the pipeline
In order not to damage the relay, it is necessary to screw it very carefully, slightly pulling it up with a wrench. The optimal distance between the product and the pipeline is at least 55 mm

When installing the factory sensor, you need to focus on the arrow shown on the housing. The direction indicated on it should coincide with the direction of flow of the fluid passing through the device.

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

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

  • a wire core is screwed to the free ends of two groups of contacts;
  • grounding is attached to the sensor screw;
  • The device is connected to the pump by connecting two devices with a conventional wire, observing the correspondence of the colors of the wires.

After connecting to the network, the matter remains small - to check the operation of the system The fact that the device is ready for full operation will be indicated by the increase in pressure marks on the pressure gauge and automatic shutdown of the pump at the moment of overcoming the limit value.

Self adjustment procedure

For adjustment in the sensor there are special bolts. Loosening or tightening them, you can reduce or increase the force of compression of the spring.

Thus, the pressure level is set at which the device will trigger.

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

In most cases, setting up automatic equipment is easy. It is advisable to adhere to the following algorithm:

  • drain fluid from the system until the pressure mark is zero;
  • turn on the pumping unit and slowly start the water back;
  • fix the flow pressure indicator when the pump is turned off by the sensor;
  • start again the drain and remember the indicators at which the pumping equipment will start to work;
  • open the relay and adjust the minimum compression level of the larger spring required for the device to activate and start the pump with an adjusting bolt (a stronger compression increases the pressure, less reduces it);
  • in a similar way, adjust the compression force of the smaller spring mechanism by setting the limits of the maximum pressure, upon reaching which the relay measuring the water flow will shut off the pump.

Having completed all the described manipulations, you should make sure that the adjustments are correct. To do this, the pipeline is filled with liquid and then drained of it, assessing the response of the sensor while it reaches the adjusted values.

If the result is not satisfactory, the procedure is repeated.

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

In order to ensure that the pipeline through which the fluid passes is working properly and stably, a regular annual check of the flow sensors is carried out. If necessary, the adjustment of operating parameters is adjusted.

Conclusions and useful video on the topic

The structure, components and principles of work:

The process of connecting the device in stages:

Details on how to adjust the trigger level in the relay:

A relay controlling the flow of water in the pipeline will significantly increase the ease of use of the pumps and prolong their service life for a long time. It is highly undesirable to neglect the installation of a safety device, since it not only automates the operation of the equipment, but also protects it to the maximum against possible malfunctions resulting from idling.

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