A prominent representative of the control valves of heating systems is the thermostat for the battery, otherwise - the radiator valve or thermostatic valve. Like other novelties in the field of heating, he came to us from Europe, and almost immediately was introduced into state building codes as a mandatory element of any water heating system. Accordingly, the purpose of this article is to disclose the principle of the thermostat and tell users how to choose, install and configure it in a home heating system.
What is the temperature controller for?
Properly selected and installed thermostatic valves can not only save energy, but also greatly simplify the life of the homeowner in terms of adjusting the temperature in the rooms. After all, using heating boilers, you can change the heating of all rooms at the same time, increasing or decreasing the temperature of the coolant. But the regulators of heating batteries make it possible to heat the premises in different ways depending on their purpose, which brings considerable energy savings.
For reference. To most modern boilers, you can connect an external heating thermostat to control heating in automatic mode. But this does not solve the problem, since a coolant with a certain temperature will still flow to all rooms at once.
The task of the thermostatic valve is to regulate the amount of coolant entering the radiator depending on the air temperature in the room, automatically maintaining it at the level that the user set. The main thing is that a sufficient amount of heated water comes from the heat source, because a temperature regulator for a radiator can only reduce its flow, but not increase it.
The device and principle of operation of the thermostat
Any automatic radiator valve consists of 2 parts:
- Thermostatic valve with actuator for shutting off the flow of coolant.
- Thermal head with a control element that responds to changes in air temperature.
The valve made of brass has a traditional mechanism with a working cone that enters the seat and thus reduces its bore. The difference from a conventional manual crane is that the cone is attached to the pressure rod with a spring exiting. Pressing the end of the rod carries out the second element - the thermal head. The stronger the click, the smaller the cross section. The diagram below shows the assembly of the heating battery regulator assembly:
Inside the thermostatic head there is a small sealed container filled with a thermosensitive medium - liquid or gas. When heated, this medium expands, the container grows and presses the stem harder, blocking the flow of coolant. When cooling, the process goes in the opposite direction, which is the principle of operation of the thermal head. A scaled adjustment knob mechanically limits maximum valve opening.
Important. The temperature regulator installed on the battery only affects the flow of the coolant, changing it in one direction or another. The thermostat is not a regulator of water temperature, that is, it performs quantitative regulation, but not qualitative.
Varieties and selection of temperature controllers
By design, radiator valves are divided into 3 groups:
- direct;
- angular;
- as part of a headset for connecting heating devices.
If everything is clear with direct and angular temperature controllers, then the headset should be said separately.It allows you to simultaneously install the thermostat on the battery and connect it to pipes coming directly from the floor. Although the price of such a headset will be higher than traditional piping, it will look much more aesthetic.
For two-pipe systems with a circulation pump for heating, any of the listed valves is suitable, the only question is how to connect the heater, and from a technical point of view they are all the same. Another thing is a one-tube scheme; for it, it is better to buy a special battery temperature controller with an increased bore of the saddle. Such thermostats have less hydraulic resistance, which is clearly seen in the diagram:
In addition to valves, you should also choose thermal heads for batteries, and here is the recommendation immediately: the valve and head should be from the same manufacturer, and the connecting threads should match. The standard thread on the valve is M28 and M30. In general, the choice of head designs is not too wide - in addition to conventional elements with an integrated bellows, there are also products with an electronic control unit and a display. These thermostats are programmable, they can be configured to maintain different temperatures in the room throughout the day.
Tip. When choosing a programmable thermostatic head, remember that it needs to be powered by batteries or mains. For the thermostat to work correctly, you will have to monitor the availability of power.
In those cases when it is planned to install heating devices behind the screens or the windows of the room are supposed to be hung with blackout curtains, ordinary thermocouples may not function correctly. Due to the weak air movement in the radiator area, the temperature behind the screen and in front of it can differ by a couple of degrees, so in addition to the temperature regulator, you should buy an external sensor with a capillary tube.
The sensor behind the screen through the capillary tube will control the thermostat, focusing on the correct temperature in the room. There is also a more advanced version in the form of an external regulator, which is also connected by a capillary tube. But here you need to be more careful: such thermal heads are not suitable for all valves, therefore, when choosing a temperature regulator, you need to consult with the seller.
Finally, a few words about the manufacturers of radiator valves. They appeared quite a lot, especially Chinese, whose quality is more than doubtful. Thermoregulators of the following brands are definitely recommended for use, their reliability is beyond doubt:
- DANFOSS;
- HERZ ARMATUREN;
- OVENTROP.
Tip. You should not buy and install thermostats on all radiators in the house. The rule is this: in order to ensure normal regulation, only batteries with a total capacity of 50% of the total and more should be equipped with temperature regulators in each room. In simple words: with 2 heaters in the room, the valve must be installed on one (which is larger), with 3 on two radiators, and so on.
Installation and setup
Before you buy and install the thermostat on the battery, you need to make sure that your heater is not equipped with a valve from the factory. This applies to steel panel radiators of some manufacturers, for example, KERMI or HEIMEIER. For them, you need to purchase only the thermostatic head itself with a suitable thread and screw it into the appropriate socket.
Setting up and installing the thermostat on the batteries with your own hands should not cause you much difficulty. Here are some suggestions:
- The valve is always installed only on the supply pipe.
- Observe the flow direction indicated on the product data sheet.
- When installing, use American women so that the assembly can always be disassembled.
- The position of the valve and head, as well as the distance to the nearest structures are indicated on the diagram:
If the temperature regulator does not provide for the function of mechanical blocking of the coolant flow, then for servicing the radiator, an additional ball valve will have to be installed in front of the valve, as shown in the diagram:
Mounting a thermal head
The element is fixed to the valve body in two ways - on the thread or by a simple click, as on DANFOSS products. In any case, you must first remove the protective cap from the valve head, then turn the handle of the head to the “max” position and insert it into the socket until it clicks or slightly tighten with a key (when the connection is threaded). If the thermostat head rotates normally, the installation is successful.
Valves of some manufacturers, as well as all heads, have a preset function. This is an advance limitation of the temperature control range, which is implemented differently in different models. For example, the HERZ ARMATUREN thermostat is limited by means of special pins; in other products, a key is used to fix the head in a certain position.
Operational adjustment of the battery thermostat is carried out by a handle with a printed scale and numbers (symbols). As a rule, the smooth adjustment range is 16–28 ° С, and in the “*” position the valve will maintain an air temperature of 6–7 ° С so that there is no defrosting.
In conclusion, a few words about the compatibility of temperature controllers with cast-iron heating devices. In principle, there are no contraindications to the installation, but there are doubts about the effectiveness of the thermostats. Cast iron batteries are massive and contain a lot of water, and therefore inertia and will be late to respond to automatic regulation. So here it is preferable to put a regular tap on the feed and balancing - on the return.