Thermal head for a heating radiator - types, selection and installation

Element types

Only the upper replaceable part of the device is called a thermal head. It can be manual, mechanical and electronic. Most of the major manufacturers of this kind of equipment make the valve body fully compatible with all types of thermocouples.

So, if the radiator has a built-in thermostatic valve, then any type of head can be installed on it. The most reliable is a mechanical part equipped with a thermostat.

There are also vandalism-proof models. Systems with remote sensors are available. Such solutions are purchased and installed if the current conditions do not allow for temperature control on the radiator itself. For example, the battery is installed behind a cabinet or dresser. The cost of such models starts from 40 euros.

Manual thermostats are the same radiator control valves. The principle of operation is the same here.

Thermal valve for heating radiator classification

Now let's talk about the bottom of the thermostat - the valve (valve). First of all, you need to know that the industry produces control devices for different systems. And you only need to use devices for your system.

Devices for two-pipe systems have at least twice the hydraulic resistance than for single-pipe systems. This is done on purpose, since balancing in this case occurs due to the pressure drop across the valves. Therefore, devices with a small flow area are installed. By placing such a device in a one-pipe system. you will be freezing for sure. Therefore, be careful.

There are thermal valves for radiators in one-pipe and two-pipe systems. And it is impossible to use devices for a two-pipe system in a one-pipe system.

Sometimes modifications for one-pipe systems are positioned as devices for systems with natural circulation. They have reduced hydraulic resistance and can be used in single tubes.

In a one-pipe system, install thermostats with a flow capacity of at least 3 (Kvs = 3 and higher).

According to the method of piping, radiator temperature regulators are angular or straight (straight). There are also axial models. In this case, they are selected depending on the type of connection of the heater. If the pipe fits from the side, it is more convenient to put a straight valve, if from below - one of the angled ones.

According to the type of connection, thermostatic valves for radiators are straight and angled

Thermal valves also differ in the material from which they are made. Metals are used that have good corrosion resistance. On some of them an additional protective coating is applied (usually nickel or chrome plating). So, thermostatic valves are made from:

bronze, nickel-plated and chrome-plated;
brass, nickel-plated;
stainless steel.

It is clear that stainless steel is better, but such valves cost a lot, and are rarely found on sale.

Classification and principle of operation of thermal heads for a heating radiator

Apart from the valve, the thermal head for the heating radiator is completely useless, since there is a sensor inside it that is triggered by a change in the temperature in the room. The bellows chamber contains a solid, liquid or gaseous substance that changes the volume.

Thermal head and valve separately

The chamber is connected to a stem that either completely closes the thermostatic valve or opens it to a regulated level.This is the main difference between a thermo-valve and a control valve, with which you can slightly reduce / add the flow of the coolant inside the heating register.

Thermal head device

Sectional view of thermal head and valve

Attention! A thermal head for a heating radiator with a valve can only be installed in bypass systems of one-pipe systems. When the valve is triggered, the flow is completely shut off, therefore, circulation in the heating circuits stops. The bypass bypass tube completely solves the problem.

Thus, a valve is first cut into the coolant supply pipe to the heating radiator, a thermal head is screwed onto it perpendicular to the fluid flow. There are several modifications of the thermal head:

for one-pipe systems - produced by a limited number of companies, for example, models RA-G, RTD-G from Danfoss;
for two-pipe systems - in any store 97% of the assortment of heads are of this type.

Thermal head for one-pipe and two-pipe heating distribution systems

You can visually distinguish the 2-pipe heads by the size of the adjusting cap and the color. Devices for single-pipe heating circuits are larger, have a gray, white color. Small diameter red caps fit on heads for high pressure, low flow 2-pipe systems.

Arrows on the body indicate the direction of flow of the heating medium; installation against the arrow is prohibited. Therefore, when choosing, it is necessary to take into account whether hot water flows from below or from above into the batteries of different rooms of the apartment.

The principle of operation of a thermal head for a heating radiator is extremely simple:

the user sets the required air temperature in the room, for which there is a scale with divisions on the device (for example, 21 degrees usually corresponds to a value of 3);

Thermal Head Scale Adjustment

when the temperature rises by 1 degree, the substance inside the bellows chamber will heat up, increase in volume, press on the valve stem;

Thermal head operation in a system without a bypass

the hot water supply to the battery will be completely shut off, however, the circulation in the heating circuits will remain through the bypass;

Structural differences between one-pipe and two-pipe systems

an idle register will lead to a decrease in temperature, the volume of the substance in the bellows will decrease, the pressure on the stem will disappear, the valve will open.

In this case, the technology for regulating the temperature regime of the room is effective only for radiators with minimal inertia. Bimetallic, aluminum, steel batteries cool / heat up faster, therefore they are optimal for automatic adjustments with thermal heads. Cast iron radiators take a long time to heat up, accumulate heat, cool down longer, so the efficiency of adjustments with thermal heads decreases.

The use of thermostats on cast iron radiators is not the best option

Thermostatic heads

There are three types of thermostatic elements for heating thermostats - manual, mechanical and electronic. They all perform the same functions, but in different ways, provide different levels of comfort, and have different capabilities.

Manual thermostatic heads work like a regular tap - turn the regulator to one side or the other, letting in more or less coolant. The cheapest and most reliable, but not the most convenient device. To change the heat transfer, you must manually turn the valve.

Manual thermal head - the simplest and most reliable option

These devices are quite inexpensive, they can be installed at the inlet and outlet of the heating radiator instead of ball valves. It will be possible to regulate any of them.

Mechanical

A more sophisticated device that maintains the set temperature in automatic mode.The basis of this type of thermostatic head is a bellows. It is a small elastic cylinder filled with a thermal agent. A thermal agent is a gas or liquid that has a large coefficient of expansion - when heated, they greatly increase in volume.

Thermostat device for a heating radiator with a mechanical thermostatic head

The bellows supports the stem that overlaps the flow area of the valve. Until the material in the bellows is heated, the stem is raised. As the temperature rises, the cylinder begins to increase in size (gas or liquid expands), it presses on the rod, which more and more overlaps the flow area. Less and less coolant passes through the radiator, it gradually cools down. The substance in the bellows also cools down, due to which the cylinder decreases in size, the rod rises, more coolant passes through the radiator, it starts to warm up a little. Then the cycle is repeated.

Gas or liquid

In the presence of such a device, the temperature in the room is quite precisely maintained at + - 1 ° C, but in general the delta depends on how inert the substance in the bellows is. It can be filled with some kind of gas or liquid. Gases react more quickly to temperature changes, but they are technologically more difficult to produce.

Liquid or gas bellows - not much difference

Liquids change volumes a little more slowly, but they are easier to manufacture. In general, the difference in the accuracy of maintaining the temperature is of the order of half a degree, which is almost impossible to notice. As a result, most of the presented thermostats for heating radiators are equipped with thermal heads with liquid bellows.

With remote sensor

The mechanical thermostatic head must be installed so that it is directed into the room. This way the temperature is measured more accurately. Since they have a fairly decent size, this installation method is not always possible. For these cases, you can supply a thermostat for a heating radiator with an external sensor. The temperature sensor is connected to the head using a capillary tube. It can be positioned at any point where you prefer to measure the air temperature.

With remote sensor

All changes in the heat transfer of the radiator will occur depending on the air temperature in the room. The only drawback of this solution is the high cost of such models. But the temperature is maintained more accurately.

Electronic

The size of the electronic thermostat for a heating radiator is even larger. The thermostatic element is even larger. In addition to electronic filling, two batteries are also installed in it.

Electronic thermostats for batteries are large

In this case, the movement of the stem in the valve is controlled by a microprocessor. These models have a fairly large set of additional functions. For example, the ability to set the room temperature by the clock. How is it fashionable to use it? Doctors have long proven that it is better to sleep in a cool room. Therefore, at night, you can program the temperature lower, and by the morning, when it’s time to wake up, it can be set higher. Conveniently.

The disadvantages of these models are their large size, the need to monitor the discharge of the batteries (enough for several years of operation) and the high price.

Mechanism adjustment

The temperature controllers for radiators are started for the first time as follows:

The system is regulated by a throttle on the return line.
The thermostatic tap on the battery opens fully.
The knob on the thermal head is removed and installed so that the maximum position on the scale corresponds to the fully open valve. The device is installed. Further temperature adjustment is made by turning the handle.
If the temperature on the display is shown in degrees, it is adjusted using a thermometer.

WATCH THE VIDEO

Using thermostats for heating radiators, you can achieve a number of advantages. With the rise in prices for supplied heat, money is saved. The device pays for itself in 1-2 seasons. Comfortable temperature conditions prevent the occurrence of colds, which occur due to frequent airing of rooms in the off-season. The heating thermostat is installed in the new heating system and in the existing one. Modern models of small sizes, fit into any interior design. The thermal head for the heating radiator must be in the heating system.

Thermal agent types

Most often, liquid and gas are used in its role. Because of this, the following types of thermal heads are distinguished:

Regulators of the first type are cheaper and simpler. For this reason, they are represented by a very large number of models. However, they run the battery more slowly.

The gas regulator for the heating battery has less inertia, due to which it is able to react quickly enough to changes in the room temperature.

In practice, the difference between the two types of response is very small.

Therefore, when choosing, it is better to focus on the quality of performance. It also depends on the manufacturer.

Almost all types of thermostats are capable of setting the temperature, the range of which is + 6 ... + 28 ° С. There are, of course, options to accommodate other temperature levels. However, as the temperature range rises, the price rises.

Thermal head operation process

The thermal head, connected to a special radiator thermostatic valve, reacts to the ambient temperature. As soon as the temperature in the room rises, the bellows of the liquid thermal head expands, as a result of which, by its movement, the valve stem reduces the flow of the coolant through the radiator. Decreasing the room temperature will reverse the action, which increases the media flow. Similar processes occur when installing an electronic thermal head. Only in this case the valve is controlled by a built-in or external thermostat, remote controller.

Types of heads by design

There are thermostatic devices according to the type of design. They are selected depending on the characteristics of the pipeline of a particular heating system and the method of installation to the radiator.

It is also necessary to take into account the peculiarity of the head installation. This node was always located horizontally. In this position, the device will be more efficient. The head will be better able to be washed by air currents.

On sale there are independent devices without radiator valves or together with them. The Danfoss thermostatic valve, for example, has just such an arrangement. But the company makes completely different systems. Instead of a scale, this product has a special diagram, according to which you can accurately adjust the settings.

But it is not always advisable to use such equipment. In this case, instead of automatic solutions, other types of valves can be used. The difference here is that the adjustment is carried out not automatically, but in manual mode. Adjustable valves and thermal heads are installed on the flow line. It is recommended to install simpler fittings at the return outlet from the battery.

Installing a thermal head on a heating radiator

Before starting work, it is important to know how to properly install the thermal head on the radiator, the further functionality of the device will depend on this.

What you need:

Thermal head
Threading dies
Fumlenta
Two adjustable wrenches
Locknuts

Preparatory work

Usually, the installation of the thermal head on the battery is carried out along with the installation of new radiators.To do this, you need to close the riser and drain the coolant remaining in the pipes into a bucket. It is best to carry out work outside the heating season.

Choosing a place to install the thermal head

Taking into account the errors in the installation of the thermostatic head, which we talked about above, we can draw conclusions about where exactly it is not worth installing the thermostatic head. What are the best options? It is important that it is not exposed to heat fluxes from the radiator and is not influenced by factors that can cause a false perception of temperature.

The photos below show common options for properly installing the thermostatic head on batteries. If it is mounted at the top of the radiator, it should only be placed horizontally. In the lower part, it can be mounted horizontally and vertically, since there are no strong heat flows of heated air - it rises upward.

Threading pipes

To fix the head on the radiator, it is necessary to cut the threads at the connection points. To do this, on the squeegees coming from the riser and the radiator, a thread is cut using a die.

Head assembly

A lock nut is screwed to the squeegee coming from the riser. It is wrapped with fumlent, and a thermostat is screwed onto it, but the fasteners are not tightened. Next, do the same with the squeegee coming from the radiator. The installed thermal head must be fastened - simultaneously tighten both nuts with two adjustable wrenches.

Thermostatic heads

- devices of a cylindrical shape, inside which there is a working substance that reacts to changes in air temperature. When the temperature changes, the volume of the working substance changes, as a result of which the valve closes. Typically, thermostatic heads regulate the temperature in the range of -6 to +30 degrees.

Thermal heads can have different working substances (liquid, gas, etc.). The range of Heimeier liquid thermostatic heads is very large. Their main advantage is an increased level of accuracy, quiet operation, simplicity and ease of use.

Gas condensate thermal heads are more sensitive to temperature changes and react more quickly to temperature changes in the room.

Most of the models of thermal heads are equipped with built-in or remote sensors, which are respectively located in the housing of the thermostatic head or outside (connection to the sensor is made using a thin metal tube).

It should be remembered that the installation of thermal heads with a built-in sensor is not so easy. For a thermostatic head of this type to work with maximum efficiency, the following conditions must be met: the depth of the radiator is not less than 16 cm, the width of the window sill is not more than 22 cm, and the distance from the window sill to the radiator is not more than 10 cm.In cases where these requirements are not possible complete, it is recommended to use thermal heads with a remote sensor, which can be located at a distance of 2 to 8 meters from the thermal head.

Installing a thermostat on a radiator

Radiator thermostats are mainly installed on the flow in front of the heater inlet. Each of the valves passes the coolant in one direction. Where the flow should go is shown by an arrow on the body. The coolant must flow exactly there. If connected incorrectly, the device will not work. Another question is that you can put a thermostat, both at the inlet and at the outlet, but observing the direction of flow. And in both cases they work the same way.

Variants of connection and installation of control valves. But to be able to repair the radiator without stopping the system, you need to put a ball valve up to the regulator (click on the picture to increase its size)

It is worth paying attention to the manufacturer's recommendations regarding the installation height. Most models should be 40-60 cm above the floor

They are calibrated to temperatures at this level. But not everywhere the feed is top. Often radiators have a bottom connection. Then, in addition to the type of system (one-pipe or two-pipe), select the installation height. If such a model is not found, you can set a lower temperature on the thermal head. If you put the recommended one, it will be too hot, since the air is cooler below, in the area of the floor, and the model is set to maintain the temperature measured at the height of the upper edge of the radiator. The second option is to configure the device yourself. The procedure is usually described in the passport, and the most common sequence of actions is described below. And the third option is to put a thermostat with an external sensor on the battery. Then it is absolutely all the same at what height the thermal head is. The main thing is the location of the sensor. But such models are much more expensive. If this is critical, it is better to tune the regulator.

Please note that the thermostatic head must be turned horizontally (looking into the room). If it is fused upward, then it is constantly in a stream of hot air that comes from the pipe.

Therefore, the substance in the bellows is almost always heated, and the radiator is turned off. The result is that the room is cold.

For the device to work correctly, you need to install it "head" in the room

The situation is a little better if the battery is installed in a niche, covered by a screen or curtain. The thermocouple is also "hot" but not so hot. Here you can go in two ways: either set a higher temperature on the regulator, or use an external sensor. Models with external thermal controllers are, of course, not cheap, but you can choose the control point of your choice.

Another thing to remember: when installing in a one-pipe system, a bypass is required. Moreover, it is unregulated. Then, when the supply on the radiator is closed, the riser will not be blocked, and you will not receive "hello" from the neighbors.

Thermal valves also differ in the type of connection: they are with union nuts, there are crimped ones. Accordingly, they are joined with certain types of pipes. Typically, the specification or description of the product indicates the type of connection, as well as with which pipes it can be used.

Thermal valve features

It was mentioned earlier that it is universal, that is, any type of thermal head can be installed on it. However, despite this, it has two varieties. They depend on which heating system the tap is to be used in. one-pipe or two-pipe.

The varieties of a thermal valve should not be neglected, because by installing a valve for a two-pipe system in a one-pipe system. the radiator will not warm up well. The reason for this is that the shut-off valve for a 2-pipe system has a high flow resistance. In fact, it is twice that of valves for a 1-pipe system. To achieve this resistance, manufacturers make small bore sizes. It also allows you to reduce the pressure on the valves and balance the pressure in the system. Because of this, under the condition of low pressure (typical for a 1-pipe system), little coolant enters through the valve.

For 1-pipe systems, valves with a flow capacity equal to or greater than 3 are suitable.

It is very simple to mount an electronic thermostat on a battery. To do this, perform the following actions:

Shut off the riser and drain the water.
A piece of pipe is cut off from the radiator. Its length must match the length of the thermostatic valve. In fact, the pipe is cut in one place.
Dismantle the part of the pipe that remains in the radiator. These steps are not performed if the heating system is only being created or if there is a valve with the same dimensions as the required valve.
Unscrew the fitting with the American from the thermo valve.
The fitting is fixed in the radiator, and the base of the faucet on the pipe.
A tap is applied to the fitting in the radiator and the American is tightened. The valve should be positioned so that the stem "points" to the side.
An electronic or mechanical thermal head is fixed.

The installation features are as follows:

the thermostat is usually placed on the inlet pipe. In this case, the arrow on it must coincide with the direction of movement of the coolant;
the electronic device must always be in a horizontal position. It is forbidden to place the thermal head over the pipe. This is because the heat from the pipe will heat the cylinder and cause unnecessary shut-off of the radiator. The consequence is a cold room;
most electronic and mechanical controls are set up for mounting at a height of 40-60 cm. If placed at a height of 10-15 cm (bottom battery connection), the room will be too warm. The problem with the bottom connection can be solved by reconfiguring the thermostat, using an external sensor or purchasing a specially designed regulator;
if the heating system is one-pipe, then the inlet and outlet pipes are correctly connected with an additional pipe. That is, it is necessary to create a bypass.

How to properly install the thermal head on the battery

Intermediate positions, when adjusting the water flow, can lead to rapid wear of the locking mechanism and its leakage.

A flare valve is a more suitable "candidate" since this valve may not be fully open / closed.

Important. The crane must be returned to its original position after a while.

The adjustment is done manually.

Regulation of batteries using an automatic regulator, otherwise, a thermostat, is carried out according to several schemes, depending on the type of heating system.

Thermostats for one-pipe heating systems

The principle of such adjustment

They are installed only if there is a connecting part between the pipes (bypass), which ensures the constant movement of water in the battery to the radiator from the coolant.

Read more about the purpose, design of the bypass here: https://kvarremontnik.ru/bajjpas-dlya-otopleniya/

For any type of heating system, the thermostat is installed in front of the radiator / radiator, strictly in a horizontal position. This compensates for the heating of the pipe and the thermostat.

When installing a control valve, the direction of movement of the heat flux must be taken into account: with vertical pipelines, the movement is set along them. On the valve, arrows are indicated by the direction of movement of the coolants.

When installing the regulator on a two-pipe system, the general requirements are observed:

installation takes place at the place of the jumper (plug) between the batteries and the coolant supply pipe;
connection is carried out with the heating system turned off and the water drained from the system;
the thermostat must be installed strictly horizontally.

Special conditions for installing a thermostat

An example of a thermostat

The thermostat operates according to the principle: when a certain temperature is reached, the gas inside the regulator expands, shutting off or reducing the supply of hot water.

Therefore, special installation conditions are required in order for the heating radiators to be adjusted correctly:

The thermostat must not be exposed to direct sunlight.
It should not be covered by curtains, screens on the battery.
The air in the room must be ventilated, especially near the device itself.

In addition, its operation is influenced by outside temperatures and sources of cold and heat.

Advice. First of all, thermostats are best installed in rooms with strong temperature fluctuations (kitchens, living rooms), as well as in the upper floors of private houses.

Read more about thermostats and how to work with them. And here is a detailed material on the installation of equipment.

Home comfort

Thermostatic element type

The thermal head for the radiator is the upper, replaceable part of the device. It can be of several types:

So that you can navigate the prices: European manufacturers sell mechanical thermal heads from 15 euros to 25 euros, there are vandal-proof models, they cost from 40 euros. There are devices with a remote sensor. They are installed if conditions do not allow regulating the temperature on the radiator (for example, it is installed behind a cabinet, closed in a niche, etc.). Here, the length of the capillary tube, which connects the sensor to the thermostat, is of great importance. Prices in this segment are from 40-50 euros.

It looks like a manual device for adjusting the temperature of radiators in section

The manual thermostat is the same control valve for the radiator. And the principle of operation is the same: rotate the knob, change the amount of the heat carrier passing through. The only difference is that, if you wish, you can simply remove this thermoelement and put in a mechanical or electronic one. At the same time, the case does not need to be unscrewed or changed. They are versatile. Heads for manual adjustment have a low price - from 4 euros.

Electronic thermal heads are the most expensive options, they are also the most massive: there is room for two batteries in the case. They differ in that they have more opportunities. In addition to maintaining a stable temperature throughout the entire time, you can program the temperature by days of the week or by time of day. For example, after 9 am, all household members leave, and appear only after 6 pm. It turns out that there is no need to spend money on maintaining high temperatures during the day. Electronic thermoelements make it possible to set a lower temperature in this interval on all days, except weekends. Put it at least 6-8 ° C, and in the evening you can again heat the air to a comfortable 20 degrees. With these devices it is possible to save on heating without compromising the level of comfort.

Electronic models have much wider functionality

Thermal heads are also divided according to the type of temperature agent (the substance that is in the bellows). They are:

A gas thermostat is considered less inertial, it is said to react more quickly to changes in temperature. But the difference is not so big as to give preference to a particular species. The main thing is quality, not the type of thermal agent. Liquid thermostats are of no less quality. Moreover, they are easier to manufacture, because they are produced in a wider range.

When choosing a thermocouple, you need to pay attention to the temperature range that the device can support. Usually it is from +6 o C to + 26-28 o C

But there may be differences. The wider the range, the higher the price. Dimensions and design, connection method are also changing.

How does a thermal valve work?

The thermal head is required to adjust the temperature of the radiator.

The very first versions of thermostats that were installed on heating radiators were created in 1943 by DANFOSS. Several decades later, such devices have undergone many changes, as a result of which they have become more accurate. Their design consists of several parts: a valve and a thermal head. Moreover, they are connected by a special locking mechanism. The purpose of the thermal head itself is to measure and analyze the temperature and influence it by using a valve mechanism for this, which opens and closes the flow of water into the radiator.

This method of regulation is also called quantitative due to the fact that the device changes the temperature by changing the amount of coolant that passes through the heating radiator. There is also another method called quality. Its principle is to change the temperature of the water directly in the system itself. This is the responsibility of the mixing unit, which is usually installed in the boiler room.

Inside such an element there is a bellows filled with a heat-sensitive medium.

Moreover, the latter can be of several types:

liquid;
gas-filled.

It is worth noting that liquid versions are easier to manufacture, but their speed is lower than that of gas ones. The essence of their work is as follows: when the temperature rises, the substance inside, according to the laws of physics, expands, due to this, the bellows expands. Further, the latter reduces the size of the valve section by moving a special cone. Ultimately, the flow rate of the coolant decreases. When the air in the room cools down, the process is reversed.

The principle of operation of the thermal valve

You can regulate the temperature using a thermal head for a heating radiator.

The first thermostats for installation on heating radiators were produced by DANFOSS in the middle of the 20th century, and already at the end of the same century, the devices underwent modernization and became more accurate.

The device consists of a valve and a thermal head connected by a special locking mechanism. The principle of operation of a thermal head for a heating radiator is to measure and analyze the temperature in the battery and adjust it using a valve that blocks the flow of the coolant.

Danfoss

This company is the inventor of the described equipment. For more than 60 years, the products of this manufacturer have embodied the best quality, high reliability and assortment. This technique can help you save a lot.

Among the popular products are the RA-N thermostatic valve. It is designed for two-pipe systems and has a built-in function for pre-setting the flow rate. The device is made in a durable cast bronze housing and is maximally protected from corrosion.

As you can see, these solutions are a great option when you need to save on heating or when it is very hot in an apartment or house. These devices can make life more comfortable.

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Principle of operation

Thermostatic valves are basically a cylinder that is filled with a heat agent (this element of plumbing is called a bellows). Liquid or gases can be used as a thermal reagent. But anything will not work for this. The volume of the coolant must depend on the temperature. There are also devices with solid components. However, they are not popular due to their long reaction times.

In the process of heating, the working substance begins to increase in volume, thereby stretching the cylinder. The latter begins to press on the piston, which in turn drives the shut-off cone on the valve.

The cone completely or partially blocks the flow of the heat agent, which is why the working substance in the thermostatic head begins to cool down. During the cooling process, the volume of the substance decreases, and as a result, the elastic element lifts the shut-off cone. The coolant will again enter the heating radiator, and the head will be heated again.

Thus, thermostatic valves help to precisely control the temperature with high precision (down to one degree Celsius).

The principle of operation of a thermal head for a heating radiator

The task of the thermostat is to control the heating of the battery with changes in the air temperature in the room. The operating procedure for all autonomous thermal heads is based on the internal structure. There is a bellows inside the body of the device - a corrugated container with a heat-sensitive substance.

The principle of operation of the thermal head:

The heated air acts on the composition, the expansion of the bellows begins.
Due to the corrugated structure, the capacity itself also increases in volume.
The expansion drives the rod, which gradually restricts the passage of the coolant into the radiator.
The throughput decreases, the temperature of the heating radiator drops.
Heating is weakened, the air cools down.
Cooling forces the bellows to compress, returning the stem to its original position.
The coolant supply is resumed with the same force.

The control of device operation is different for different types of models. Each type has its own precision in adjusting the thermal head of the radiator, ease of use and cost.

The divisions define the border of the rod movement

How to choose

When choosing a thermal valve, you need to take into account all the existing features of the heating system

Based on the characteristics of the heating system, as well as the conditions of its installation, in order to control the temperature, it is possible to use various combinations of valves and thermal heads.

So, for example, valves with a higher flow capacity should be used for use in one-pipe systems.

The same applies to those two-pipe systems in which the circulation of water is carried out by gravity, that is, in a natural way, without forced mechanisms. In cases where a two-pipe system is used, where there is a circulation pump, it is recommended to select those types of valves where it is possible to adjust the throughput.

After choosing the valve, it is necessary to select the thermal head.

The most common options that can be purchased today are:

having an internal thermoelement;
electronic (which can be programmed);
having an external temperature sensor;
anti-vandal;
having an external regulator.

Most often, classic thermostats with an internal version of the sensor are installed in cases where their axis will be in a horizontal position.

Please note: the thermostat must not be installed vertically, since the heat emanating from the body piping will strongly affect the bellows, due to which the entire device will not function correctly.

In cases where it is not possible to mount the head horizontally, it is best to install an additional external temperature sensor with a special capillary tube.

In addition to vertical installation options, there are also other reasons to purchase a remote sensor version:

in the event that heating radiators with a temperature controller located on them will be located behind the curtains;
when there is any other heat source next to the installed thermal head;
if the location of the battery is under a large windowsill.

Very often, in those rooms where the requirements for the interior are increased, the batteries are covered with decorative screens. Due to this, the internal thermostat will only register the temperature that is inside this casing. This will block access to the thermal head adjustments. Therefore, in such cases, it is recommended to stop your choice on a remote controller with a thermal sensor.

Worth knowing: if you have not yet purchased heating radiators, you can buy Kermi models with built-in temperature sensors.

If we talk about electronic thermostats with a display, then they are of several types, the former have a built-in control unit, and the latter have a removable one. The latter have the feature of the ability to detach from the thermal head, while it will continue to work in the same mode. The purpose of such models is to implement temperature control in different modes, at different times of the day. This makes it possible to reduce the level of heat during the day, and at night, when the whole house is asleep, to raise it to the desired level. Due to this, it is possible to significantly save energy.

If there are small children in the family who always want to touch and twist everything, it is recommended to install anti-vandal thermostats. This will protect the device settings from unauthorized interference. The same situation applies to options installed in various public buildings, ranging from kindergartens to hospitals.

Types and types of thermal heads

Thermostats today are designed for two main heating systems, which had a major impact on the separation of these elements by type. So, there are thermal heads for one-pipe heating systems, and, of course, two-pipe. The installation of a thermal head on a heating radiator is also carried out based on a certain type of heating system. Large pressure drops are under the force of the second type of thermal heads. Due to the high resistance of the hydraulics inherent in the control valves, it is possible to achieve pressure losses in these places.

Within this type, there is also a certain division into thermal valves with a preset resistance setting and thermal valves without this setting. The second option allows you to achieve equal indicators of the level of flow of heat carriers in all heating devices, but this is not a positive factor. Since each room has its own indicators of heat loss, then the heaters in it must be installed with the appropriate power, this is exactly what the adjustable valves allow.

Of course, setting the necessary parameters will allow you to achieve optimal results from the radiators, which, in turn, will warm up the room to the required level. That is why the installation of the thermal head on the radiator is so important. At the same time, it is important to remember that the control system with such parts must necessarily be supplemented with bypass valves, which will eliminate the interfering noise resulting from pressure drops. (See also: How to calculate bimetallic heating radiators)

The installation of a thermal head on a heating radiator should be chosen not only in relation to the type, but also in relation to the type. So, manual thermal heads have a scale with numbers and a snowflake, which greatly facilitates setting the required temperature. In this case, setting the indicator at zero mark will indicate the disconnection of the device.

A positive feature of the manual thermal head is that it is easy to mount in any position. This can be both horizontal and vertical. Horizontal installation will facilitate subsequent conversion to a bellows analog. The presence of curtains, or any other curtains overlapping the head with a bellows, will negatively affect its operation, therefore, in this case, it is best to install a manually controlled element. However, this situation may well be corrected by installing additional remote sensors.

Setting the thermostat

For the correct setting of the temperature controller, it is necessary to reduce to the lowest possible heat loss in the room. The thermometer should be located where there will be a constant temperature. After that, we turn the head of the thermal regulator to the left to the end, opening the valve, as a result of which the maximum heat transfer is achieved. As soon as the temperature increases by 5-6 degrees, the valve is closed by turning the head in the opposite direction.

After reaching the required temperature level, we begin to carefully open the valve. The setting ends when the sound of water in the regulator is heard and the rapid heating of the valve becomes noticeable.

It is best to entrust the installation of thermostats on heating radiators to professionals who will connect according to the manufacturer's instructions. Correctly installed equipment will allow you to create an optimal temperature regime in the room and ensure a rational consumption of thermal energy, which will have a beneficial effect on the financial costs of the family.

Thermal head setting

After the user got acquainted with the design of the device, learned how the thermal head works on the heating radiator, setting the optimal microclimate in each room is not difficult. By turning the knob relative to the scale with marks, you can adjust the temperature within the range of +5 - +28 degrees.

In the first case, the system is guaranteed not to freeze in the absence of the owners inside the building of periodic operation. The maximum value is considered comfortable for users. The substance with which the bellows chamber is filled reacts to an increase / decrease in temperature within 1 degree. Therefore, valve on / off cycles will occur regularly.

Thus, any home craftsman can select and mount the thermal head together with the valve. To do this, it is enough to take into account the above factors, to avoid major installation errors.

The thermal head in 90% of cases is used to lower the air temperature. However, in a country cottage, by installing heads with valves on all registers, the temperature can be raised. In rooms farther from the boiler, the heat loss in the heating circuit is maximum. Therefore, when the supply is cut off in the near registers, hot water heats up the ones far from the boiler room better.

Special thanks to the authors of articles from the sites: homemyhome.ru, vseinstrumenti.ru, o-trubah.ru, nastroike.com