Control valves for radiator thermostats RA are classified into two types: RA-N(for two-pipe pump heating systems) and RA-G(for one-pipe pumping and two-pipe gravitational systems) 1). The RA-N valve is a valve of increased hydraulic resistance with preliminary installation setting of its maximum flow capacity. Valves are produced with nominal diameter from 10 to 25 mm, straight and angle, nickel-plated. The Danfoss range includes a modification of the DN = 15 mm RA-NCX valve with a chrome body, which is usually used in conjunction with RAX thermocouples in chrome or color. Valves RA-N CX are used in rare cases, and RA-N valves DN = 10 and 25 mm are generally not used in Russia, therefore they are not presented in this manual. Angle horizontal and three-axis valves are used when it is necessary to use a thermostatic element with a built-in sensor and the pipelines supplying the heat carrier to the heater are laid from below. The Danfoss range also includes a RA-N DN = 15 mm valve with a pressure connection for a copper pipe ø15x1 mm, which is used in horizontal apartment heating systems. Technical information for RA-N valves DN = 10 and 25 mm , RA-NCX and RA-N DN = 15 mm for press connections are presented in catalog VD.53.P17.50 "Radiator thermo-regulators and pipe fittings for hot water heating systems". RA-N valves are supplied with a red protective cap.

The main advantage of valves Danfoss type RA-N - convenience and accuracy of adjustment to the required hydraulic resistance (throughput). In valves from other manufacturers, the setting is the number of revolutions of the special tool from the closed position. In this case, it is impossible to determine the value of the setting visually without disturbing the existing position of the device. It will not be accurate either, since it is not clear how many revolutions, for example 3 or 3 ¼. The presence of a special tool complicates the adjustment work. Externally, the same valves from different companies have different fixed settings. During installation, builders often confuse them and in the future cannot establish the heating system. Some companies offer to make the setting not on the thermostat-regulator, but on the shut-off valve, changing the number of revolutions of its stem. This is inconvenient, as it leads to a rise in the cost of work and a decrease in the accuracy of adjustment.

The presetting device is a throttling cylinder associated with a rotary crown. The different positions of the crown and cylinder correspond to the specific flow rates of the thermostat valve. On the crown, numeric indices of the positions of the tuning element are indicated. The setting indices must be determined during the hydraulic calculation of the heating system and set against drilling on the valve body during installation and commissioning work. Tuning is done without the use of any tool. The adjusting device is hidden under the thermostatic element and, when it is blocked, becomes inaccessible for accidental readjustment. In case of possible clogging of the valve at low presetting values, it is enough to turn the adjusting crown to the "N" position (fully open), and the valve is flushed with water. After that, the setting returns to its original position. The presetting values ​​are clearly visible on the crown (it is easy to set up or check the correctness of the setting). Each valve has 14 fixed setpoints (settings 1 to 7, N and six intermediate positions).

RA-G - a valve of low hydraulic resistance without a device to limit its capacity. The valves are manufactured with a nominal diameter of 15 to 25 mm with a nickel-plated body. They can also be straight and angled. The manual does not present the RA-G valves DN = 25 mm, since they are not practically used in Russia. Technical information on them is presented in catalog VD.53.P17.50 "Radiator thermostats and pipe and wire fittings for hot water heating systems". The RA-G valves are supplied with a gray protective cap. The RA-N and RA-G dampers are connected to the heating devices using threaded shanks with a union nut, and with the pipeline through a coupling socket. If necessary, a special version of RA-N valves can be used in heating systems - with an external connecting thread or with a fitting for a press connection with a copper pipe ø15x1 mm. Many Russian factories produce heating devices with built-in Danfoss thermostat valves. Among them are the Moscow plant Santekhprom, which produces a bimetallic radiator Santekhprom-BMN Auto and convectors with a casing of the Santekhprom Auto series; JSC "Mechanical Plant" (St. Petersburg) - steel panel radiator of the "Konrad-Thermo" type; plant "Radiator" (Kimry) - steel tubular radiator of the "RS" type, etc. Convectors and steel radiators are equipped with thermostat valves for both two-pipe and one-pipe heating systems. Other devices with built-in thermostats are intended for two-pipe systems only. Danfoss thermostat valves built into a heater are generally similar in design and hydraulic performance to the RA-N and RA-G stand-alone thermostat valves. Specifications Russian heating devices with thermostats are given in the passports of manufacturers heating equipment, in the relevant materials of Danfoss LLC, and also included in the database of the Danfoss S.O. program for calculating heating systems on personal computers.

The main advantage of Danfoss RA-G valves- high throughput (RA-G DN = 20 mm has Kv = 2.06 m3 / h at Xp = 2 ° C). This is important in one-pipe heating systems to achieve optimal values ​​of the coefficient of flow of the coolant from the riser to the heater. High flow capacity is obtained due to the large valve seat area and increased stroke (more than 30% when using a thermostatic element with gas condensate filling compared to liquid-filled thermostats). These valves are the only ones with such a capacity that have the European quality certificate EN215. This is due to their ability to tightly shut off the coolant flow through the heater when the room temperature rises by 2 ° C more than the calculated one. In addition, the valve presents a unique service capability: its seat and plug can be completely replaced on site if required (without dismantling the valve).

RA-N valve for two-pipe pump heating system; PN = 10 bar, Tmax. = 120 ° C, with internal thread

Valves for two-pipe heating system RA

RA-N valve intended for use in two-pipe pumping systems for hot water heating with copper or stainless steel pipelines. Special crimping tools are required to connect the valve fitting to the pipeline.

RA-N valve for two-pipe pump heating system; PN = 10 bar, Tmax. = 120 ° С, for press connection with the pipeline. It is possible to use tools from Geberit Mapress, REMS, Rothenberger, SANHA, Viega

RA-G valve for one-pipe pumping and two-pipe gravitational heating systems; PN = 10 bar, Tmax. = 120 ° C, with internal thread

Control valve RA-G has an increased throughput and is intended for use in pumping one-pipe water heating systems with closing sections (bypasses).

Thermostat RA consists of two parts:

• universal thermostatic element of the RA 2000 series - automatic temperature control devices;
• control valve with pre-setting of the flow rate RA-N (for two-pipe heating systems) or RA-G (for one-pipe system).

The production program for thermostatic elements of the RA 2000 series includes:

• RA 2994 and RA 2940 with built-in temperature sensor, frost protection of the heating system, temperature setting range 5–26 ° C, device for fixing and limiting the temperature setting. Unlike RA 2990, the RA 2940 thermocouple additionally has a function that ensures 100% overlap of the thermostat valve;
• RA 2992 - thermoelements with a remote sensor, frost protection of the heating system, a temperature setting range of 5–26 ° C, a device for fixing and limiting the temperature setting;
• RA 2920 - thermoelements with a cover that protects against unauthorized interference, a built-in sensor, frost protection, a temperature setting range of 5–26 ° C, a device for fixing and limiting the temperature setting;
• RA 2922 - thermoelements with a cover that protects against unauthorized interference, a remote sensor, frost protection, a temperature setting range of 5–26 ° C, a device for fixing and limiting the temperature setting.

RA 2992 and RA 2922 are equipped with an ultra-thin capillary tube 2 m long, which is located inside the housing of the remote sensor, connecting it to the working bellows of the thermostatic element. During the installation process, the tube is pulled to the required length.

RA 5060/5070 series - a number of remote control thermoelements with frost protection of the heating system, temperature setting range 8-28 ° C, device for fixing and limiting temperature setting:

• RA 5062 - with a capillary tube length of 2 m;
• RA 5065 - with a capillary tube length of 5 m;
• RA 5068 - with a capillary tube length of 8 m;
• RA 5074 - with capillary tube length 2 + 2 m.

All thermostatic elements can be combined with any RA type control valves.

The clip-on connection allows simple and precise fastening of the thermocouple to the valve.

The protective cover of the RA 2920 and RA 2922 thermocouples prevents unauthorized disassembly and adjustment by unauthorized persons.

Technical characteristics of RA type radiator thermostats comply with European standards EN 215-1 and Russian GOST 30815-2002.

1) Remote sensor Supplied with capillary tube fully wound inside the sensor box. When installing the sensor, unwind only the required part of the tube.

2) The temperature scale is calibrated for Xp = 2 ° C. This means that the valve closes completely when the room temperature exceeds the setting temperature by 2 ° C.

3) A brass handle must be used to seal off the valve in a pressurized system and to dismantle the heater.