Thermal head for radiators: types, operating principle, installation

Thermal heads for radiators are needed to create an optimal temperature regime in the house. The heating function is more effective in determining all the heating points of the system - in each separate room. Manual adjustment of heating can not ensure high accuracy and timeliness of making compensations.

Why it is necessary to put the thermostat?

When using the thermal head for radiators, the heating system becomes more efficient. The flow of hot water through the pipe decreases with time when the outside temperature of the air increases, thereby reducing the heating power.

Conventional valves are used in classical heating systems. Also common are ball valves having a number of features:

• They are used only in two positions: opening and closing. It is difficult to set intermediate positions, and the risk of leakage outside the extreme positions of the ball increases. This lacks thermal head for radiators.
• There is no automatic control, all water flow adjustments are done manually.
• The ball valve immediately applies pressure to the system, which can lead to mechanical damage to the radiator tubes and joints.
• Thermal heads for radiators use natural physical properties and can operate autonomously without additional maintenance.

Device devices

Consider the insides of the thermal head for radiators. The principle of the device is based on the use of physical quantities: the force of spring stretching and the expansion of gases under the influence of temperature effects. Outwardly it looks like a corrugated shell, changing in size.

The stock of spring strength is sufficient for the entire service life of the device. Thermal heads can be without power and with it: from the battery and the network. Simple designs are preferred, but systems with a remote sensor are more accurate.

Sensors are used for the temperature converter: solid (springs or plates), liquid (the principle of operation as in a thermometer), gas (substances lighter than air). The heating agent in the radiator can be water or a specialized liquid with additives. The last moment should be considered when choosing the type of thermal head.

What should I consider?

With a competent design of the heating system, a thermal head for the radiator is used. The testimonials of experienced plumbers show that automatic adjustment saves money, consumes resources, and also frees a person from constant temperature control in the room. The set heating value will stay within the manufacturer's specified error.

However, the installer's errors will cause a huge deviation of the indicators due to the following factors:

• Sensitive sensor capsule should be placed in a horizontal position. It is recommended to install the device at the base of the radiator. If this can not be avoided due to pipe wiring, the following conditions are taken into account.
• The sensor capsule must be open. Curtains, furniture, decorative grilles and close proximity to wall coverings interfere with the correct operation of the sensor.
• If the location is inevitably in the niche, then a thermal head for a radiator with a remote sensor is used. The sensing element is located directly on the wall in the room, but not above the radiator. Avoid places with a draft, where often cold air moves from windows and doors.
• It is not recommended to cover the thermal head with curtains, and also to set the sensing element vertically with the horizontal assignment of the device.

Accuracy introduces installation of the radiator and sensor directly under the wide sill, which delays heated air and distorts the measurement results. In the packaging of most devices there is a product passport, but not all the conditions for the correct location are indicated there. Only experienced installers are able to accurately take into account even such an insignificant for the layman nuance, as a draft due to an open window.

How does the system work?

The sensor device can be schematically represented as a conventional valve or a tap with a thermal head for a radiator. In contact with hot liquid there is a thermostatic valve, in the simplest form representing a spring with a piston. The resilient member is connected to a working volume in which a gaseous substance that is sensitive to temperature is located.

The clamping force is adjusted by the rotary dial knob, so the desired temperature is set in the room. Depending on it, there is a piston blocking the flow of liquid. The device is mounted with union nuts, this allows you to change the element when the parts of its construction fail. Provide additional fluid supply through the ball valves, in the event of a breakdown of the automatic control system.

What determines the heat transfer of radiators?

The type of connection of heating pipes affects the efficiency of the entire system. According to the experts-installers, the best way is to connect the radiators "from below-down". Such designs exhibit an optimal loss of heat transfer coefficient and a minimum number of connections.

One-way or series connection of radiators is less effective. The last element in the chain practically does not heat, and the first one heats the room up to values of uncomfortable temperature. A versatile method of supplying pipes occurs in private houses with an enviable popularity, with this type there is an entrance on one side, and drainage of liquid from the other.

In the latter case, the heat loss will be 12%. A versatile method is optimal in terms of power distribution, but the design requires a lot of space and a number of connections. Thermal heads themselves are subdivided according to the installation method:

• Angle - are needed in parallel connection systems and with horizontal supply.
• Direct - are used in the sequential scheme of laying pipes.

It is possible to use any connection scheme, it is recommended to take into account the nuances of mounting radiators and thermal heads only before carrying out the work.

Sensor features

Thermal heads for radiators with a lower connection are needed when using a heating system in private houses. One-story buildings do not tolerate unnecessary communications, so pipes to the radiator are drawn from the floor. With this arrangement of the sensor, additional positive moments appear:

• Down there is cold air, and control takes place at the coldest point in the room.
• The most accurate regulation occurs when the thermal heads are installed on each individual supply. But such measures are more costly.
• More accurate temperature measurements are obtained by connecting the radiators with separate parallel branches. Through each pass bypass pipeline, and the connection to the feeds occurs at a height of not more than 5 cm. Thus, high efficiency of the heating devices is achieved.

Types of producers

The leading brands in the production of heating systems are the following:

• Panel radiators Kermi (Germany) are equipped with thermal heads Oventrop;
• Bimetallic Rifar (Russia);
• Tubular Zehnder (Germany);
• Steel panel Prado (Russia).

Kermi radiators are popular: therm-x2 plan-v typ11 smooth, therm-x2 profil-v profile. It occurs in the markings: FTV, PLV - with the bottom line; FKO, PLK - with side; Ph O - hygienic.

Types of locking and regulating equipment for radiators:

• "Ouentrop" - manufacturer Germany: multiflex series CE for single-pipe systems; Series ZB for two-pipe; ZBU is customizable; F - in the composition of brass and soft seal. Oventrop uni with integrated valve.
• Danfoss - the following types: RA5062, RA5065, RA2920, RA2940, RA2994, RA5068, RA5074. They differ constructively and are designed for a certain power of the radiator.

Each manufacturer produces competitive models that differ in cost and principle of operation. Consider two types of thermal head for radiators: Danfoss and Oventrop.

The first type of heating regulators

Oventrop is a thermal head for the radiator "Kermi", and also pipes under this brand are produced. The manufacturing plant supplies its products with shut-off valves of this type only. Plastic pipes "Ouentrop" have a coating EVON, which is a protection against the harmful effects of oxygen.

Thermal heads "Oventrop" for radiators have been tested in production. Liquid controllers allow to create an optimal control system for heating, to reduce the consumption of resources and to maintain the required temperature with a given accuracy. Installed them in the radiators Kermi.

The second type of heating regulators

Thermal head for Danfoss radiators can be made in the following variations:

• RTD-G - more throughput, the diameter of the connection is greater. They are used in a single-pipe heating scheme or in private houses, when a two-pipe system is not equipped with a circulation pump.
• RTD-N - the scheme of approach to radiators two-wire, the circulation pump is present.

For Danfoss models RA2920, RA2940, RA2994, only the horizontal placement of the regulator is selected. Take into account items that introduce measurement errors in the incorrect installation of instruments on radiators. Convection flows should be considered when choosing a vertical sensing element.

For the Danfoss RA5062, RA5065 models, a long capillary tube, this design reduces measurement errors at any location of the thermal head. Types RA5068 or RA5074 are used in inaccessible areas, they have a remote temperature sensor.

Regulator selection parameters

The first point when choosing the shut-off and control equipment becomes the type of heating system: one-sided, versatile, "bottom-down". The second is already the dimensions of the sensor and valve design, throughput, temperature range. Of no small importance is the type of sensing element: gas, liquid, solid.

Gas filling is more sensitive to changes in ambient air temperature. However, accuracy is lost. Liquid thermal heads change the flow with fluctuations in magnitude by a fraction of a degree. The method of mounting and location of the sensor, the variant of information display is selected.

There are models with remote control, with LCD screen when working on batteries. Because of its practicality, the distribution has received the simplest designs with an integrated sensor.

Installation method

Remote control is required when installing radiators inside the enclosures, under the grilles, in a recess. Installation of the thermal head begins with the evacuation of the heating system. Before draining, it is recommended to cool the radiator so as not to burn yourself. The materials of the thermal head construction are rather soft and the tightening of the fastening nuts is not recommended.

It will be better to use a torque wrench. On the body of the device there is a flow direction indicator, for correct operation it is better not to confuse it. After the assembly of the sensor, the optimum temperature is adjusted and the liquid is put into the system.

It is recommended that air be released from the pipes and radiator. To do this, there is a drain valve, which is unscrewed and a part of the liquid merges into a special container until the bubbles finish.

Additional measures and servicing of regulators

The selected sensor temperature is maintained automatically. The heating system requires annual maintenance after the cold season and before the winter begins. The liquid often spoils without the use of coarse filters and when tap water is used as the working material.

Rust appears inevitably due to poor quality parts of the boiler, pump, shut-off valves. Solid impurities appear from the boiling of the liquid. During operation, it is recommended that you periodically check the heat of each radiator to the touch.