Construction and installation of a balancing valve for a heating system

In any heating system consisting of several radiator batteries, their heating temperature depends on the distance to the heating boiler - the closer to it, the higher the degree. Therefore, for its efficient operation and to ensure various requirements for heating the premises, a balancing valve for the heating system is built into the line.

There is a wide range of these control valves on the construction market, which have the same principle of operation and some differences in design. It is useful for any master or owner who independently conducts heating in his private house to know what a balancing valve is needed for, the rules for installing and adjusting it to ensure the efficiency, economy and functionality of the heating main.

Fig. 1 Thermal imaging of a residential building with unbalanced heating

What is a balancing valve

To maintain the same temperature in the batteries, they are adjusted by changing the water flow - the less coolant passes through the radiator, the lower its temperature. You can shut off the flow with any ball valve, but in this case it will not be possible to set and adjust the same temperature in the devices if the number of heating devices is more than one. It will have to be measured with temperature sensors on the surface of the batteries and by rotating the valve by an experimental method to set its desired position.

Balancing valves commonly used for tuning effectively solve the problem of maintaining balance automatically or by simple calculations of the required flow rate and the corresponding settings in the devices. Structurally, the device partially blocks the flow of the heat carrier, reducing the cross-section of the pipes similarly to any shut-off valve, with the difference that the required volume of supply is precisely set according to the setting scales using the rotary handle of the mechanism or automatically.

Principle of operation

First, let's figure out the main nuances of balancing heating devices. In the event that a dead-end branch of the pipeline is connected to several heating radiators, each of the heating devices must be supplied with a sufficient amount of preheated water. The required volume of liquid is taken from a preliminary calculation.

Sectional balancing valve

If the batteries are not equipped with a thermostat valve, then the water consumption for each individual consumer will be constant. To regulate the fluid supply in the system, you can use a manual balancer, which is installed on the return line at the junction of the pipe with the common line.

In the future, the valve must be set to the required number of revolutions - to increase or decrease the diameter of the hole. In this case, it is possible to achieve the normal flow rate of the coolant in the branch. But what if the fluid flow rate in the system is constantly changing?

In this situation, a balancing valve will come to the rescue of the user, which controls the heating of the room by creating an obstacle to the flow of liquid. During the operation of such a device, the volume of the coolant supply decreases.

Note! When using a manual balancer, effective operation of 4-5 heaters is possible.

If there are more users than the specified number, then each of the batteries will receive an unequal amount of heat. After blocking the water flow on the first radiator, the amount of liquid will increase on the second one, but in this case the valve will not close, and the excess hot water will go further.As a result of such work, some batteries will overheat, while others will receive less coolant. Balancing valves are required to regulate the system.

Functioning diagram

The principle of operation of our device is as follows: when the valve is installed at the maximum flow rate of the coolant, the thermostat installed on any of the radiators will reduce the consumption of the heated liquid. The result of this process will be gradually increasing pressure.

After a while, the capillary tube will indicate to the device an increasing pressure, which will lead to an adjustment of the coolant flow rate. The rest of the thermostats on other heating devices will not have time to completely shut off the liquid, and this will lead to balancing the pressure and the consumption of the coolant in the system.

Why use

The installation of balancing taps in the heating system, in addition to maintaining the same temperature of the batteries, in an individual house has the following effect:

• Accurate regulation of the coolant temperature allows you to set its value depending on the purpose of the premises - in living rooms it can be higher, in utility rooms, storerooms, workshops, gyms, food storage areas, using balancers, you can set it to a lower value. This factor increases the comfort of living in the house.
• Changing the coolant flow using a balance valve regulator, depending on the purpose of the premises, brings a significant economic effect, allowing you to save on fuel.
• In winter, in the absence of owners, constant heating of the home is necessary - using balancing valves, you can achieve a heating system setting with minimal fuel consumption and maintaining a constant temperature in all rooms. This advantage also saves the owners' financial resources.

Fig. 3 Manual balancing valves for heating and hot water (DHW) systems in the home

Design and principle of operation

The principle of operation of the balancing valve consists in shutting off the fluid flow with a sliding valve or a stem, which causes a decrease in the cross-section of the flow channel. The devices have a different design and connection technology; in the heating system, they can additionally:

1. Maintain the differential pressure at the same level.
2. Limit the flow rate of the coolant.
3. Shut off the pipeline.
4. Serve as a drain for the working fluid.

Structurally, balancing valves resemble conventional valves, their main elements are:

1. Brass body with two internal or external threaded ports for connection to standard pipe diameters. Connection in the pipeline in the absence of a threaded fitting with a movable threaded nut (American) is made through its analogs - additional transition couplings with different union nuts.
2. A locking mechanism, the movement of which regulates the degree of overlap of the heat carrier passage.

Fig. 4 Danfoss LENO MSV-B manual balancing valve device

1. Adjustment knob with scale and setting indicators to regulate the flow inside the instrument.
2. Modern models are equipped with additional elements in the form of two measuring nipples, with the help of which the flow volumes (throughput) are measured at the inlet and outlet of the device.
3. Some models are equipped with a shut-off ball mechanism to completely shut off the flow, or have a function to drain the liquid from the water supply.
4. High-tech modern types can be controlled automatically, for this, instead of a rotary head, a servo drive is installed, which, when supplied with electricity, pushes the locking mechanism, while the degree of channel closure depends on the magnitude of the applied voltage.

Fig. 5 Automatic balancers Danphos AB-QM - design

Design feature

A quality part includes reliable components:

• Robust brass body with threaded pipe connections. Inside the product there is a saddle in the form of a special vertical channel.
• Adjusting spindle. The working part is represented by a cone that is screwed into the saddle. As a result of the activation of the spindle, the coolant flow is blocked.
• Rubber sealing rings.
• The cap is usually made of plastic. There are also metal options.

A distinctive feature of the device is the presence of two special fittings.

They are responsible for the following functions:

1. Determined by the pressure inside the system, both before and after the valve.
2. Connect a capillary tube.

Each of the nozzles measures the pressure, and if a difference in values ​​is detected on the regulating mechanism, the water flow is calculated.

Types of balancing valves

Balancing in heating systems is carried out using two types of control valves:

• Manual... The design is a body made of non-ferrous metals (bronze, brass), in which a balancing element is placed, the degree of extension of which is set by turning a mechanical handle.
• Automatic... Automatic devices are installed on the return pipeline together with valves of partners who are able to limit the flow of the medium by presetting the throughput. When connected, they are connected to partners via an impulse tube that connects to the built-in test nipple. If the valve is installed to supply water in a straight line, its handle is red; when installed in a return line, it is blue (Danfoss models). Automatic types are models controlled by a servo drive, which is supplied with constant voltage.

BALLOREX valves

The Polish company BROEN BALLOREX in its Venturi series produces a manual balancing valve with high control accuracy. Such a valve is a valve that has two functions:

• manually adjustable valves;
• shut-off ball valve.

It allows balancing and hydraulic regulation, limiting the flow, opening and closing the flow of the working medium in the system, as well as measuring the temperature of the working medium and the flow using a standard flow meter. It can be purchased in various designs. The range of these valves is produced with nominal diameters from DN 15 to DN 200 and nominal pressure PN 16 Var and PN 25 Var. Valves with nominal diameters from DN 15 to DN 50 and pressure 16 var are flanged, and valves with pressure PN 25 var are threaded.

BROEN BALLOREX valve

All balancing valves and their elements (valve body, orifice plate, shut-off ball, control stem) with nominal diameters from DN 15 to DN 50 are made of chrome-plated brass. Balancing valves with nominal diameters from DN 65 to DN 200 are made of steel with flange or threaded connections.

Valves of the Venturi series with the same nominal size are produced with different flow capacities, depending on the type of execution: high (H), standard (S) and low (L). In addition, the Venturi series is produced in two types - Venturi FODRV and Venturi DRV, these valves have flow control measuring nipples. All valves of this company can be installed in any position in any section of the pipeline before or immediately after a branch, before or after a narrowing of the pipeline.

Also, this Polish company offers automatic balancing valves in various modifications.Ballorex DP valves are installed in the return line, providing the required pressure drop across the circulation ring under all loads. This makes it possible to stage-by-stage commissioning of the facility due to the possibility of zone balancing. The use of Ballorex DP allows you to eliminate noise phenomena that are caused by overpressure created in other parts of the heating system.

Valves from a Danish manufacturer

Another manufacturer is the Danish company Danfos, which supplies valves of all types with high quality performance. MSV-BD LENO ™ manual valves are a new generation of valves. They allow solving problems of hydraulic balancing of heating systems. In doing so, they combine the functions of a standard manual valve and a ball valve, thus ensuring a quick and complete shutoff of the flow. Most models allow you to take data at the outlet and inlet, but some models have a nipple only on one side.

Automatic valve ASV-M

Automatic ASV-M, the price of which allows us to speak about the optimal ratio of price and quality, can be used as a shut-off valve and, if necessary, connect an impulse tube from ASV-P (V). ASV-I. It allows you to limit the maximum flow rate of the transported coolant. The valve is equipped with special plugs for measuring nipples. By installing the nipples, you can measure the flow rate of the coolant that flows through a specific section of the system.

Valves of the ASV series are characterized by high quality workmanship. They make it possible to maintain a constant pressure difference between the supply and return pipelines. The return line ASV-P has a fixed setting of 10 kPa. Whereas ASV-PV has a measurable setting of 5-25 kPa and ASV-PV Plus has 20-40 kPa.

Balancing valve for heating system

The existing heat supply systems are conventionally divided into two types:

• Dynamic. They have conditionally constant or variable hydraulic characteristics, these include heating lines with two-way control valves. These systems are equipped with automatic differential balancing regulators.
• Static. They have constant hydraulic parameters, include lines with or without three-way control valves, the system is equipped with a static manual balancing valve.

Fig. 7 Balancing valve in line - installation diagram of automatic fittings

In a private house

A balance valve in a private house is installed on each radiator, the outlet pipes of each of them must have union nuts or another type of threaded connection. The use of automatic systems does not require adjustment - when using a two-valve design, the supply of coolant to radiators installed at a great distance from the boiler is automatically increased.

This is due to the transfer of water to the actuators through the impulse pipe under a lower pressure than the first batteries from the boiler. The use of another type of combination valves also does not require the calculation of heat transfer using special tables and measurements, the devices have built-in regulating elements, the movement of which is carried out using an electric drive.

If a manual balancer is used, then it needs to be adjusted using measuring equipment.

Fig. 8 Automatic balancing valve in the heating system - connection diagram

To determine the volume of water supply to each radiator and, accordingly, balancing, an electronic contact thermometer is used, with which the temperature of all heating radiators is measured. The average delivery volume for each heater is determined by dividing the total by the number of heating elements.The largest flow of hot water should go to the farthest radiator, a smaller amount to the element closest to the boiler. When carrying out adjustment work with a manual mechanical device, proceed as follows:

• All control valves are opened all the way and water is connected, the maximum surface temperature of the radiators is 70 - 80 degrees.
• A contact thermometer is used to measure the temperature of all batteries and record the readings.
• Since the farthest elements must be supplied with the maximum amount of heating medium, they are not subject to further regulation. Each valve has a different number of revolutions and its own individual settings, so it is easiest to calculate the required number of revolutions using the simplest school rules based on the linear dependence of the radiator temperature on the volume of the heat carrier passing through.

Fig. 9 Balancing valves - installation examples

• For example, if the operating temperature of the first radiator from the boiler is +80 C., and the last +70 C. with the same supply volumes of 0.5 cubic meters / h, on the first heater this indicator is reduced by a ratio of 80 to 70, the consumption will go less, and the resulting volume will be 0.435 cubic meters / h. If all the valves are set not to the maximum flow, but to set an average indicator, then the heaters located in the middle of the line can be taken as a reference point and similarly reduce the throughput closer to the boiler and increase it at the farthest points.

In a multi-storey building or building

The installation of valves in a multi-storey building is carried out in the return line of each riser; with a large distance of the electric pump, the pressure in each of them should be approximately the same - in this case, the flow rate for each riser is considered equal.

For setting in an apartment building with a large number of risers, it uses data on the volume of water supplied by an electric pump, which is divided by the number of risers. The obtained value in cubic meters per hour (for Danfoss LENO MSV-B valve) is set on the digital scale of the device by rotating the handle.

Operating principle

Balancing valves are designed to maximize the efficiency of all heating elements of the system, as well as adjust it at any time.

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The principle of operation of the device is that the valve changes the flow area by means of the work of the parts.

When a knob designed for adjustment is turned to either side, torque is transmitted to the nut and spindle. Unscrewing causes the last element to rise from the bottom to the top. Being at the bottom, it tightly blocks the flow, not allowing the coolant to pass through the pipes.

Thus, when the valve is unscrewed, the valve passes a certain amount of energy carrier, increasing the passage, when twisted, the passage narrows, which reduces or completely blocks the flow. Turning the spindle changes the throughput of the device.

Any adjustment of the flow area entails a change in the resistance of the valve to the flow of water or any other coolant.

Water, like any other energy carrier, always follows the path of least resistance. As a result, distant heating circuits do not heat up sufficiently. The balancing valve creates artificial resistance in the path of water, accelerating its flow into the distant circuits. Thus, the device provides the calculated pressure drop.

In such work, the main task of the entire structure is to ensure maximum tightness. For this, manufacturers use several options for O-rings:

• from fluoroplastic;
• made of dense rubber;
• made of metal.

For fine tuning, you need to study the technical specifications, which describe the operation of the system at certain shutter positions.

Valve installation

When installing the valve, place it in the direction of the arrow on the body, which indicates the direction of movement of the fluid, to combat turbulence that affects the accuracy of the settings. Choose straight sections of the pipeline with a length of 5 diameters of the device and its location point and two diameters after the valve. The equipment is installed in the reverse branch of the system, a plumbing adjustable wrench is sufficient for the work, the installation is carried out in the following sequence:

• Before installation, be sure to flush and clean the pipeline system to get rid of possible metal shavings and other foreign objects.
• Many devices have a removable head; for ease of installation in pipes, it should be removed in accordance with the instructions.
• For installation, you can use linen fiber with an appropriate lubricant, which is wound on the end of the pipe and the outlet of the battery.
• The regulating valve is screwed onto the pipe with one end, the second is connected to the radiator with special washers (American adapter coupling), which is placed on the outlet radiator fitting or screwed into the valve, playing the role of a coupling.

How to adjust the balance of the radiator network

Each valve comes with an instruction manual when you buy it, which contains information on how to calculate the number of handle turns.

With the help of the attached diagram, you can permanently adjust the energy consumption, saving on heating.

According to the instructions, you need to turn the valve to a certain level.

There are two ways to adjust the valve.

Method 1

Experienced technicians have a simple and proven way to adjust the system.

They divide the valve speed by the number of radiators located around the entire perimeter of the room. It is this method that allows them to accurately determine the flow rate adjustment step. The principle is to close all the taps in the reverse order - from the last to the first radiator.

For a more illustrative example, let's take the following characteristics of the system.

The dead-end system has 5 batteries, which are equipped with manual valves. The spindle in them is adjustable by 4.5 turns. Divide 4.5 by 5 (number of radiators). The result is a step of 0.9 revolutions.

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This means that the following valves must open the following number of revolutions:

Method 2

There is another, very effective way to adjust. It is carried out faster, and includes the ability to take into account the individual features of each of the radiators. But to carry out such a setting, you will need a special contact-type thermometer.

The whole process proceeds in the following sequence:

1. Open all valves without exception and let the system reach an operating temperature of 80 degrees.
2. Measure the temperature of all batteries with a thermometer.
3. Eliminate the difference by closing the first and middle taps. In this case, the latter mechanisms do not need to be regulated. As a rule, the first valve is turned by a maximum of 1.5 turns, and the middle ones by 2.5.
4. Do not make any adjustments for 20 minutes. After adapting the system, measure again.

The main task of this method, like the previous one, is to eliminate the difference in temperature with which all batteries in the room are heated.

Balance Valve Setting

To balance heating in a private house, manual devices of the required diameter are selected, making their selection and adjustment using the appropriate diagram attached in the passport. The initial data for working with the graph are the delivery volume, expressed in cubic meters per hour or liters per second, and the pressure drop, measured in bars, atmospheres or Pascals.

For example, when determining the position of the adjustment indicator of the MSV-F2 modification with a nominal diameter of DN equal to 65 mm. at a flow rate of 16 cubic meters / h. and a pressure drop of 5 kPa. (Fig. 11) on the graph, the points on the corresponding scales of flow and pressure are connected and the line is extended until the conditional scale crosses the coefficient Ku.

From a point on the scale Ku draws a horizontal line for a diameter D equal to 65 mm., Find the setting with the number 7, which is set on the scale of the handle.

Also, for the selected diameter of the device, its adjustment is carried out using the table (Fig. 12), according to which the number of spindle revolutions corresponding to a certain flow is determined.

Fig. 11 Determining the position of the valve scale at a known pressure and a certain water supply

Fig. 12 Example of a table for manual adjustment

How the installation is carried out

It is very important to ensure that the valve is in the correct position during installation. In this case, the arrow on the body must coincide with the direction of movement of the coolant

This position will provide not only the required design valve resistance, but also the required flow rate. At the same time, it should be noted that some manufacturers allow the possibility of installing the valve not only in the direction, but also against the flow. The stem, at the same time, for most models, can occupy a different spatial position.

During the installation process, it is worth protecting the working bodies of the valve from the ingress of various mechanical contaminants. To do this, a mud collector or a special filter must be installed in front of the valve. To eliminate turbulent fluid movement, it is necessary to provide straight sections of sufficient length before and after the valve. This requirement is mandatory specified in the documentation for the valve.

A heating system equipped with a balancing valve must be filled in a special way. For this, in systems equipped with dynamic valves, it is imperative to provide filling connections, which must be located in the immediate vicinity of the valve on the return pipeline. And valves mounted on the supply pipeline must be closed prudently. A special flow meter or differential pressure and flow tables are used to adjust the balancing valve. However, in any case, the initial calculation is performed even at the stage of calculating the heating system.