Optimal microclimate in the greenhouse: installation of thermostats.

Installing meters and believing that savings have been achieved is a delusion. Don't stop there! Having studied the market of energy-saving equipment properly, it comes to the understanding that real savings begin with the installation thermomiser. After all, this device should be used in every heating and hot water supply system! The thermostat is automatic regulator temperature, as hot water, and coolant. By equipping your system with a thermomiser, you get the ability to control the climate in any room and huge savings in hot water or heat carrier consumption, and as a result, money.

How does a thermometer work?

The thermomiser consists of only two components, this is a regulator and electronic device management. The first component, the regulator, is responsible for automatically regulating the temperature of the supply water for the heating or hot water supply system. The second component of the thermomiser is an electronic device that receives data from temperature sensors located inside and outside the room, as well as at the inlet and outlet of the coolant. The received data is processed in accordance with the program algorithm, calculations are made, according to which commands are sent directly to the controller.

What can thermostats do?

By selecting various programs, we have the ability to maintain the set water and heat carrier temperatures, the schedule of the heating system, adjust the temperatures of the return circuit, the heat carrier in the supply pipe according to the deviation from the set internal temperature of the room, adjust when using a timer, separate modes for holidays, weekends and nights and a number of other options. Thermomisers are equipped with rich functionality and saving opportunities, we only need to select the right model, set the right data and set the mode.

An important detail in saving is the equipment of the device outdoor sensor, this is especially true for spring, during sharp changes in temperature at night and day. When monitoring the entire dynamics of differences, we always have the temperature we need inside the room without overspending resources and money.

Which thermostat to choose?

Thermizer should be chosen based on the existing water supply and heating system. Any thermomiser model will effectively save the coolant and create the necessary microclimate in the room. Depending on the type of regulator, some thermomisers can be used in public and administrative buildings, others will be more relevant in open system hot water supply and heating, the third type of thermomisers is better applicable in closed systems with pump mixing, or as an additional option in ventilation systems and air conditioning systems. The most influencing factor in the savings of a thermomiser is the type of regulator.

Our factory manufactures and supplies all the lineup the following temperature controllers:
thermomiser R-2.T, thermomiser R-7.T, thermomiser R-8.T, Teplur control device and other components of ultra-efficient energy saving equipment. You can seek advice on the selection, purchase, delivery, installation and configuration of thermomisers using the contacts indicated on the product page.

How long do thermostats last and how are they used?

In terms of service life, thermomisers are practically eternal, but the quality of the coolant has a direct dependence on the lifetime of the device. Considering the realities, the thermomiser will work freely for 15-20 years. Our factory manufactures regulators from high-quality metals such as stainless steel, brass and cast iron, which has a positive effect on the durability and smooth operation of the devices. This gives significant advantages over imported devices - competitors made of carbon steel, manufactured by Danfoss, etc. The quality of the primary Russian coolant is significantly inferior to the European one, for which imported thermal misers are designed, their operation in domestic systems will be accompanied by many problems.

Thermomisers in maintenance are not whimsical at all. Basically, no Maintenance and not required. It is enough to set up the controller once initially. It is recommended to delegate installation to professionals.

Benefits of installing a thermostat

Often, when the coolant passes through the heating system circuit, it does not cool down and has a high enough temperature to use it again. This is exactly what is done with a thermometer. Due to the secondary use of the coolant, we achieve significant savings. Administrative, residential and public buildings can be connected according to this scheme.

For the time when we do not use the premises, for example, on weekends or holidays, you can set minimum temperature coolant on the thermomiser, which will entail a significant reduction in coolant consumption.

Thermomisers also save money thermal energy in production and retail space. For this energy you have to pay a lot of money on the meter. Just imagine what kind of overpayment is received for weekends, holidays, night time and other cases when the premises are not used. For all these cases, you can set up certain modes in the thermomiser controller and not pay extra money for overspending the coolant.

The advantages of thermomisers are expressed not only in money, do not forget about comfort. After all, the possibility of adjusting and maintaining the temperature at the required level is relevant for many rooms of various buildings and areas.

I want to talk about the creation of a simple device that greatly facilitated the life of home inhabitants - an automatic temperature controller for a geyser. Similar devices have already been created and described here on Habré, I wanted to make a slightly more advanced device and describe in detail the entire creation process from idea and measurement to implementation, without using ready-made modules Arduino type. The device will be assembled breadboard, programming language - C. This is my first development of a complete (and working!) device.

1. Initial data

We live in a rented apartment, which has one very unpleasant property: there is no hot water in the house, cold water is heated on the spot using a heater (Fluent Gas Water Heater - HSV) located in the kitchen. While taking a shower, if another pressure surge occurs, you have to spank naked to the column or call someone. Integrate a complete smart House» there is no possibility, so it was decided to introduce automatic regulation of the heater. By the way, I quickly found several similar solutions, for example, which means that my problem is known and solved in its own way.

VPG model: Vector lux eco 20-3 (China)
Water pressure: about 1.5 kgf / cm² (pressure is low, the heater operates slightly above the allowable limit)

Solution Requirements

• Simplicity
• PID controller or similar
• Possibility to choose the maintained temperature
• Display of current parameters
• Resolving Device Security Issues

System architecture

After some thought, the architecture of the device was sketched out as follows:

• Servo drive (directly in the body of the HSV)
• Thermal sensor regular HSV
• Thermal sensor signal amplification unit and servo power supply stabilizer (directly in the body of the HSV)
• Control unit (external)

Next, I will describe the development process in chronological order.

2. Servo

Since my profession is software engineering and mechanics has always been the most difficult part, I decided to start with it. I must say that I could not get ready for the first stage for a long time, it was very scary to touch the HSV, but another pressure drop forced me to start.

Having dismantled the column and looked around, I found places to install the TowerPro MG995 servo, somehow ordered “for delivery” on aliexpress a long time ago.

To eliminate the backlash of the drive rods, I made one rod spring-loaded. The backlash was completely eliminated, but another problem turned out - a servo with a torque > 10 kg * cm turned out to be too bold for the HSV. When turned on, the transients in the electronics of the machine cause a jerk to a random position, and after a couple of idle turns, the rod turned out to be bent! Silumin columns will definitely not withstand such treatment. The geometry of the rocker, which was not on the axis of the regulator, also caused criticism, which led to non-linearity of the adjustment. The final view of the throttle drive assembly:

The unit has been redone - springs from the VAZ were used (from the carburetor - bought at an auto parts store) and the rocker is now on the geometric axis of the shaft. This design has a small backlash, but it is linear in adjustment and can dampen the fury of the steering machine. The corners are set to optimal values for adjustment in the most demanded positions of the regulator.

3. HSV sensor unit

The HSV thermistor changes its resistance within 20..50 KΩ, it is problematic to use it directly as a divider - we get low measurement accuracy. But as it turned out in practice - with an increase in the supply voltage to 12V, you can easily get an acceptable output signal range - just use the op-amp in repeater mode (if necessary, you can change the gain) to isolate the divider from the load. Block diagram inside the HSV:

The divider R2 and the column temperature sensor generate a signal with a voltage of 1.4..4.96 V in the full measurement range (in practice - 20..60 degrees Celsius). Initially, he developed a bridge circuit - which can compensate for the loss of the power source, but was discarded due to the fact that the power source had little effect, and the first point of the "TK" was - "simplicity". The operational amplifier provides decoupling of the divider and the load. The zener diode D1 limits the output voltage to 5.1 V in cases where the sensor is disconnected (otherwise the output would be 12V - which is deadly for the controller) - which will be considered an unconditional error by the controller circuit. The integrated stabilizer 7805 feeds the servo - the solution is unsuccessful, when the machine stops, it heats up terribly and I think it can fail if the drive wedges (if the built-in protection does not work). I will not focus on this block anymore.

4. Controller

The controller is assembled on the basis of the Atmega8 IC in a dip-package.

Clocking - internal oscillator at 8 MHz. Power - another 7805 on the board. Indication via standard LCD1602 display. Block diagram:

The power supply of the unit is controlled from the column through a transistor - using a small-sized relay. The temperature sensor signal (Contact No. 4 of the connector) has a pull-up to ground and when the sensor is disconnected during operation, it will show a very high temperature - which will lead to a decrease in the regulator and will not cause dangerous situations. Assembled block:

4. Testing and adjustment

To test the PID controller, a HSV model was written in Qt. It worked out the main points and situations of the heater operation - cold / hot start, pressure drops. To take the characteristics, a UART connector was added to the controller board, where data on indicators were sent once a second - the current temperature, throttle position, etc.

The tests revealed the following:

• Very large HSV inertia from the beginning of exposure to the reaction on the temperature sensor - about 30 seconds
• Rounding to a degree in the controller firmware is a bad idea, the algorithm could work more accurately

The results of measurement and calibration of the temperature sensor, The dependence can be considered conditionally linear:

The first runs in the program for rendering telemetry from the column:

(I forgot to add a legend to the charts. Here and below - red- sensor temperature, green dotted- throttle position, blue- temperature desired by the user)

Almost a successful adjustment

Good odds options

Good start option

The first runs showed the main parameters of the system, then it was not difficult to measure them and adjust according to the accelerated formula, the parameters were selected for a long and painful time. It was not possible to get rid of fluctuations completely, but fluctuations within 1 degree are considered acceptable. Accepted option:

In the process of selection, the integral coefficient had to be completely turned off, I think that this is due to the large inertia of the system. Final odds:

FloatPk = 0.2; float Ik = 0.0; float Dk = 0.2;

5. Enclosure

The device is assembled in a plastic junction box.

And it works like this.

6. Safety of use

An important question that was asked from the very beginning. Let's go through the main points.

Galvanic isolation of column and regulator circuits

What happens if the 12V power supply short-circuits and there is 220 volts on the sensor circuit? This will not cause gas to flow into the column. As it turned out - it will not cause - there are two levels of gas supply in the column - solenoid valve controller and mechanical water valve. It is not enough to open only the solenoid - gas will not flow without water flow.

Disconnection or detachment of the sensor inside the HSV

When the thermistor is disconnected from the block inside the VPG, a 0xFF (5.1V) signal will be generated at the output, which is checked by the program as an error, the controller stops the program execution, the servo drive is set to a minimum.

Disconnection or detachment of the sensor from the controller

In this case, a high temperature is generated (pulling the sensor line to the ground) which will lead to the output of the drive to the minimum value, which is also safe for the user.

Electronic-mechanical protection of HSV

HSV protection prices remain functional in normal mode, in case of boiling / overheating / column draft sensor, standard systems should turn it off.

Temperature is an indicator of the thermodynamic state of an object and is used as an output coordinate in the automation of thermal processes. Characteristics of objects in temperature control systems depend on the physical parameters of the process and the design of the apparatus. So general recommendations it is impossible to formulate temperatures for the choice of ACP and a careful analysis of the characteristics of each specific process is required.

Temperature control in engineering systems ah is performed much more often than the regulation of any other parameters. Range controlled temperatures small. lower limit this range is limited minimum value outside air temperature (-40 °C), upper - maximum temperature coolant (+150 °С).

To common features ACP temperature can be attributed to the significant inertia of thermal processes and temperature meters (sensors). Therefore, one of the main tasks in the creation of ACS temperature is to reduce the inertia of the sensors.

Consider, as an example, the characteristics of the most common manometric thermometer in engineering systems in a protective case (Fig. 5.1). block diagram such a thermometer can be represented as a series connection of four thermal containers (Fig. 5.2): a protective cover /, air gap 2 , walls of the thermometer 3 and working fluid 4. If we neglect the thermal resistance of each layer, then the heat balance equation for each element of this device can be written as

G,Cpit, = a n? sjі ( tj _і - tj) - a i2 S i2 (tj -Сн), (5.1)

where Gj- the mass of the cover, air layer, wall and liquid, respectively; Cpj- specific heat capacity; tj- temperature; a,i, and /2 - heat transfer coefficients; S n , S i2 - heat transfer surfaces.

Rice. 5.1. circuit diagram manometric thermometer:

• 1 - protective cover; 2 - air gap; 3 - thermometer wall;
• 4 - working fluid

Rice. 5.2.

As can be seen from equation (5.1), the main directions for reducing the inertia of temperature sensors are;

• increase in heat transfer coefficients from the medium to the case as a result of the correct choice of the sensor installation location; in this case, the velocity of the medium must be maximum; ceteris paribus, it is more preferable to install thermometers in the liquid phase (compared to gaseous), in condensing vapor (compared to condensate), etc.;
• reduction of thermal resistance and thermal capacity of the protective cover as a result of the choice of its material and thickness;
• reduction of the time constant of the air gap due to the use of fillers (liquid, metal chips); for thermocouples, the working junction is soldered to the body of the protective cover;
• selection of the type of primary converter: for example, when choosing, it must be taken into account that a thermocouple in a fast-response design has the smallest inertia, and a manometric thermometer has the largest.

Each temperature ACP in engineering systems is created for a very specific purpose (controlling the temperature of the air in the premises, heat or coolant) and, therefore, is designed to operate in a very small range. In this regard, the conditions for the use of one or another ACP determine the device and design of both the sensor and the temperature controller. For example, in the automation of engineering systems, direct-acting temperature controllers with manometric measuring devices are widely used. So, to regulate the air temperature in the premises of administrative and public buildings when using ejection and fan coils of a three-pipe heating and cooling circuit, a direct-acting regulator is used direct type RTK (Fig. 5.3), which consists of a thermal system and a control valve. The thermal system, which proportionally moves the control valve stem when the temperature of the recirculation air changes at the inlet to the closer, includes a sensitive element, a setting device and an actuator. These three nodes are connected by a capillary tube and represent a single hermetic volume filled with a temperature-sensitive (working) liquid. A three-way control valve controls the supply of hot or cold water to the ejection heat exchanger

Rice. 5.3.

a - regulator; b - control valve; c - thermal system;

• 1 - bellows; 2 - setter; 3 - tuning knob; 4 - frame;
• 5, 6 - regulating bodies respectively hot and cold water; 7 - stock; 8 - actuating mechanism; 9 - sensing element

closer and consists of a body and regulatory bodies. With an increase in air temperature, the working fluid of the thermal system increases its volume and the valve bellows moves the stem and the regulating body, closing the passage of hot water through the valve. With an increase in temperature by 0.5-1 ° C, the regulatory bodies remain motionless (hot and cold water passages are closed), and with more high temperature only the cold water passage opens (the hot water passage remains closed). The set temperature is provided by turning the adjustment knob connected to the bellows, which changes the internal volume of the thermal system. The controller can be set to temperatures ranging from 15 to 30°C.

When controlling the temperature in water and steam heaters and coolers, RT type regulators are used, which differ slightly from RTK type regulators. Their main feature is the combined design of the thermocylinder with the adjuster, as well as the use of a two-seated valve as a regulating body. Such gauge regulators are available in several 40-degree ranges ranging from 20 to 180 °C with nominal diameters from 15 to 80 mm. Due to the presence of a large static error (10 °C) in these controllers, they are not recommended for high-precision temperature control.

Manometric thermosystems are also used in pneumatic P-regulators, which are widely used to control temperature in engineering air conditioning and ventilation systems (Fig. 5.4). Here, when the temperature changes, the pressure in the thermal system changes, which acts through the bellows on the levers that transmit force to the pneumatic relay rod and the membrane. When the current temperature is equal to the set one, the entire system is in equilibrium, both valves of the pneumatic relay, supply and bleed, are closed. When the pressure on the stem increases, the supply valve begins to open. It is supplied with pressure from the mains. compressed air, as a result of which a control pressure is formed in the pneumatic relay, increasing from 0.2 to 1 kgf / cm 2 in proportion to the increase in the temperature of the controlled medium. This pressure activates the actuator.

For automatic regulation room temperature, thermostatic valves from the American company began to be widely used Honeywell and radiator thermostats (thermostats) RTD, issued by the Moscow branch

Rice. 5.4.

with manometric thermosystem:

• 1 - pneumatic relay rod; 2 - node of unevenness; 3, 9 - levers;
• 4, 7 - screws; 5 - scale; 6 - screw; 8 - spring; 10 - bellows;
• 11 - membrane; 12 - pneumatic relay; 13 - thermal bulb; 14 - feeding

valve; 15 - bleed valve

Danish company Danfoss, the required temperature is set by turning the adjusted handle (head) with a pointer from 6 to 26 °C. Lowering the temperature by 1 °C (for example, from 23 to 22 °C) saves 5-7% of the heat consumed for heating. thermostats RTD allow avoiding overheating of the premises during the transitional and other periods of the year and provide a minimum required level heating in rooms with periodic residence of people. In addition, radiator thermostats RTD provide hydraulic stability for a two-pipe heating system and the possibility of adjusting and linking it in case of errors during installation and design without using throttle washers and other constructive solutions.

The temperature regulator consists of a control valve (body) and a thermostatic element with a bellows (head). The body and head are connected with a threaded union nut. For ease of installation on the pipeline and connection of the thermostat to the heater, it is equipped with a union nut with a threaded nipple. The room temperature is maintained by changing the water flow through heater(radiator or convector). The change in water flow occurs due to the movement of the valve stem by a bellows filled with a special mixture of gases that change their volume even with a slight change in the temperature of the air surrounding the bellows. The elongation of the bellows with increasing temperature is counteracted by a setting spring, the force of which is adjusted by turning the handle with an indicator of the desired temperature value.

To better suit any heating system, two types of regulator housings are available: RTD-G with low resistance for single pipe systems and RTD-N with high resistance two-pipe systems. Bodies are manufactured for straight and angle valves.

Thermostatic elements of regulators are manufactured in five versions: with built-in sensor; with remote sensor (capillary tube length 2 m); with protection against misuse and theft; with setting range limited to 21 °С. In any version, the thermostatic element ensures that the set temperature range is limited or fixed at the desired room temperature.

Service life of regulators RTD 20-25 years, although the Rossiya Hotel (Moscow) registered a service life of 2000 regulators for more than 30 years.

Control device (weather compensator) ECL(Fig. 5.5) ensures the maintenance of the temperature of the coolant in the supply and return pipelines of the heating system, depending on the outdoor temperature according to the corresponding specific repair and a specific heating schedule object. The device acts on the motorized control valve (if necessary, also on circulation pump) and allows you to perform the following operations:

• maintenance of the calculated heating schedule;
• night drop temperature chart by weekly (interval 2 h) or 24-hour (interval 15 min) programmable clock (in the case of an electronic clock, the interval is 1 min);
• heating of the room within 1 hour after the night temperature decrease;
• connection via relay outputs of a control valve and a pump (or 2 control valves and 2 pumps);

Rice. 5.5. Weather compensator EC/. with setting,

available to the consumer:

1 - programmable clock with the ability to set operating periods for comfort or reduced temperature on a daily or weekly cycle: 2 - parallel movement of the temperature graph in the heating system depending on the outside temperature (heating graph): 3 - operating mode switch; 4 - a place for the instruction manual: 5 - signaling the inclusion, the current mode of operation,

emergency modes;

O - heating is turned off, the temperature is maintained to prevent freezing of the coolant in the heating system;) - operation with a reduced temperature in the heating system; © - automatic switching from mode comfortable temperature to the low temperature mode and back in accordance with the setting on the programmable clock;

O - work without lowering the temperature on a daily or weekly cycle; - manual control: the regulator is off, the circulation pump is always on, the valve is controlled manually

• automatic transition from summer mode in winter and back according to the set outdoor temperature;
• termination of the night temperature decrease when the outside temperatures fall below the set value;
• protection of the system from freezing;
• correction of the heating schedule according to the air temperature in the room;
• switching to manual control of the valve drive;
• maximum and minimum supply water temperature limits and the possibility of fixed or proportional

temperature limitation return water depending on the outdoor temperature;

• self-testing and digital indication of temperature values ​​of all sensors and states of valves and pumps;
• setting the dead zone, proportional band and accumulation time;
• the ability to work on the accumulated over a given period or current temperature values;
• setting the coefficient of thermal stability of the building and setting the influence of the return water temperature deviation on the supply water temperature;
• protection against scale formation when working with gas boiler. In engineering systems automation schemes,

also bimetallic and dilatometric thermostats, in particular electric on-off and pneumatic proportional.

The electric bimetal sensor is mainly intended for on-off temperature control in rooms. The sensitive element of this device is a bimetallic spiral, one end of which is fixed, and the other is free and satisfies moving contacts, closing or opening with a fixed contact, depending on the current and set temperature values. The desired temperature is set by turning the setting dial. Depending on the setting range, the temperature controllers are available in 16 modifications with a total setting range from -30 to + 35 °C, with each controller having a range of 10, 20 and 30 °C. Operation error ±1 °С at the middle mark and up to ±2.5 °С at the extreme marks of the scale.

The pneumatic bimetallic regulator as a transducer-amplifier has a shutter nozzle, which is acted upon by the force of the bimetallic measuring element. These regulators are available in 8 modifications, direct and reverse action with a total setting range from +5 to +30 °C. The setting range of each modification is 10 °С.

Dilatometric regulators are based on the difference in the coefficients of linear expansion of an invar (iron-nickel alloy) rod and a brass or steel tube. These thermostats do not differ in the principle of operation of control devices from similar regulators using a manometric measuring system.

1.
2.
3.
4.

As you know, in order to heat any room with high quality, it is necessary to correctly adjust the temperature indicators so that the heating matches optimally. comfortable conditions and provided a favorable microclimate in the dwelling. Therefore, it is necessary to consider in more detail the features of such a device as a temperature controller for a heating radiator, which is designed to perform all these functions. In addition, you should figure out how to regulate the temperature of the radiator in various buildings, including private and apartment buildings.

The need to install thermostats

Such mechanisms are used for the following purposes:

• saving heat produced by heating;
• maintaining a comfortable temperature in the home.

Many owners to solve the second problem still use traditional ways such as covering radiators with a blanket or opening windows for ventilation. However, much more modern solution there will be the installation of such a device as a heating temperature controller, which affects the flow rate of the coolant in the heating system and is capable of functioning both in manual and automatic mode.

It is very important to remember that during installation it is extremely necessary to have a special jumper located directly in front of the heating device. If it does not exist, then the coolant flow cannot be regulated through the radiator, since this will have to be done through a common riser.

Speaking of savings, this factor is relevant for those owners whose living quarters are equipped with an autonomous heating system, as well as for housing and communal services that use metering devices to pay for heat coming from its producers.

Installation of temperature controllers in apartment buildings

To set the radiator temperature controller to apartment building, it is necessary to understand what constitutes heat accounting in such a design.

The supply and return pipelines are equipped with special retaining washers, before and after each of which there are pressure regulating sensors. Due to the fact that the diameter of these sensors is known, it becomes possible to calculate the flow rate of the coolant circulating through the sensors. As a result, the difference obtained between the water flow in the supply and return pipelines will reflect the amount of water used by the residents.

Temperature sensors are designed to control both areas. Therefore, knowing how much heat is consumed and what its temperature is, you can easily calculate the amount of heat that remains in the room.

In order to regulate the operation of heating was easier, you need to constantly monitor the state of the temperature.

This can be done in one of two ways:

1. Mounting shut-off valve . Such a device is designed to partially shut off the pipeline system if the return temperature is higher than the set one. It is a conventional solenoid valve. This option will be suitable for those houses where the heating system is relatively simple and does not have a large volume of coolant.
2. Valve device three way type . This device also allows you to adjust the current flow rate of the coolant, but it functions a little differently: in the event that the water temperature exceeds the norm, then it is sent through open valve into the supply pipeline more. By mixing with cooled water, the overall temperature will decrease, while the required circulation rate will be maintained.

Similar design may differ slightly in different systems. The device circuit can be equipped with several temperature sensors, as well as one or two circulation pumps. Also, valves may be present. mechanical type, with which you can control the operation of heating without supplying any power.

Installation of mechanical regulators is not particularly difficult. To install such a device, you only need to connect it to the flange in the elevator assembly. It is also important that the price of such devices is much lower compared to electronic mechanisms.

Installation of temperature controllers in private homes

As a rule, an automatic heating temperature controller is an integral part of a heating boiler in autonomous system heating. Such a sensor can be mobile, that is, it can be carried, and is also capable of measuring the temperature in the room.

Electric boilers use electronic sensors, which are directly connected with the installed heating elements (thermal electric heating elements) or with the voltage that occurs on the electrodes or on the boiler winding.

Boiler systems operating both with gas and pyrolysis technology are often equipped with mechanical regulators, the main advantage of which is independence in terms of energy. But this option, of course, does not imply the use of remote temperature sensors. See also: "".

Temperature sensors for radiators

Sometimes one temperature sensor carries several heating radiators. First of all, the installation scheme affects this. But it is much more common to mount the regulator on each heating device separately.

Many owners install a system familiar to many, called "Leningrad", the principle of which is to use one pipe encircling a house or one floor, which has a rather impressive diameter, and radiators or convectors are built in parallel with it.

It is worth noting that in order to adjust the heating temperature, you can use not only standard devices.

Common mechanisms of this type include:

• thermostatic head. Represents automatic sensor, which controls the temperature of the coolant in the battery. The principle of its operation is as follows: in the process of heating, liquid and gaseous substances expand (details: ""). This, as a consequence, leads to the fact that the heated product squeezes out a special rod, thereby blocking the access of the coolant;
• devices called chokes are no less often used. They are special taps. screw type, with which you can adjust the permeability of the coolant manually. Their cost is more affordable, and in addition, they can be used to control two-pipe heating systems;
• The least expensive and simplest mechanism to help regulate temperature is the traditional valve. Of course, in this case, only modern models should be used, and not outdated screw devices, since valves often come off in old mechanisms, and there is also a risk of oil seals leaking. The situation is completely different with ball valves: even in the half-open position, they function reliably and efficiently over a long period of time.

In order for the device of temperature controllers to be as convenient as possible, many experts recommend that you first study various photos these devices and detailed videos on their correct connection.

An example of heating temperature controllers on video:

Automatic regulation is very convenient. With the help of a thermostat for greenhouses, you can maintain the required air temperature in the building.

Types of thermostats and their characteristics

There are many types of thermostats. To do right choice, you need to know their features. There are 3 main types.

1. Electronic thermostat. It has a liquid crystal display, which makes it possible to obtain accurate information about the status.
2. Sensory devices. The good thing is that you can set a work program in them, which makes it possible to create different temperature in different time days.
3. mechanical product. Most easy installation to control soil temperature. In this case, the temperature is set once, and then you simply adjust it. Perfect option for small greenhouses.

How to choose a thermostat

When choosing a thermostat, you should be guided by what you want to receive in the end. First of all, you should pay attention to the following characteristics:

• installation features;
• control method;
• appearance;
• power;
• the presence or absence of additional functions.

When choosing thermostats for greenhouses Special attention power is worth it. It must be greater than the required ground heating power. Take with a margin! In this case, all work is controlled by a sensor. He can be:

• external;
• hidden.

A chain can consist of several elements. Appearance thermostats are also different. Installation can be either hinged or hidden.

Installation Features

When installing the system with your own hands, you should know that the regulator operates from sensors - illumination and temperature. During the day, the temperature in the building will be higher, at night it will be lower. Depending on this, the heating also changes. The parameters for the thermostat are:

• illumination limit - from 500 to 2600 lux;
• deviation in the power supply of the device - up to 20%;
• temperature range - from +15 to 50 degrees;

• at the transition of the illumination limit, the difference in temperature value is up to 12 degrees;
• accuracy is about 0.4 degrees.

When installing the system with your own hands, you should know that the thermostat includes a correction unit and a temperature control unit. You can run them on transistors. The switch allows you to change the temperature. The relay can be combined with a heating device for the stove using contacts. The controller may have an output relay that controls the heating.

The sensors include photoresistors and thermistors. They respond to various changes in environment. You can set the settings according to the instructions provided by the manufacturer.

You should set up the installation with your own hands, starting with grading the scale of the resistor. First, the sensors are lowered into heated water, and then the temperature is determined. Next is the calibration of the light sensor. It is allowed to assemble the temperature controller inside the greenhouses. It is placed near a heating device, which can be a stove.

Overview of the thermostat (video)

How to work with a thermostat

Thermoregulators, regardless of whether they are made by hand or purchased in a store, are very similar in principle of operation. Because of this, it is easy to work with them. What characterizes the work with the device?

• A special button helps to scroll through the menu.
• The temperature is controlled manually.
• You can store settings in the machine's memory for quick start-up.
• The use of special buttons allows you to control the operation of the boiler and stove, set the heating characteristics.
• If there is a display with readings, you can find out what the heating is at a given time period.

Among other things, thermostats make it possible to control the boiler for heating the greenhouse.

1. After the controller is powered up, the sensors are polled for real-time information. Then the controller compares the readings and the already recorded information for the day or night and selects the necessary settings for the thermostat.
2. After 5 minutes, the thermostat is activated, and the boiler starts working.
3. If the heating is insufficient, the heater with the pump starts to function. A command is given to increase the fuel supply, which increases heating.

Thermostats are multifunctional. With their help, you can heat the greenhouse and set the required temperature for the air in the building, as well as heat the soil and water.

The controller is able to support optimal conditions environment in any . Some devices turn on and work independently, which is very convenient. Connect them to the controller, heat sensors, stove and boiler. Ultimately, control over temperature regime possible to the fullest.

Making a simple do-it-yourself regulator

You can make a regulator with your own hands from a standard household thermometer. However, it will have to be modified.

• First, disassemble the device, but remember to proceed with caution.
• In the scale, at the location of the area of ​​the required control limit, a hole is made. Its diameter should be less than 2.5 millimeters. A phototransistor is fixed opposite it. Sheet aluminum is taken, a corner is made in which a 2.8 mm hole is drilled. The phototransistor is glued to the "Moment" glue in the socket.
• A corner is fixed below the hole so that when the temperature rises (during the day), the arrow does not have the opportunity to pass the hole. This will prevent the heating from turning on when it is not needed.
• With outer side a 9-volt bulb is installed on the thermometer. A hole is drilled in the body of the thermometer for it. A lens is placed inside between the scale and the light bulb. It is necessary for the device to work accurately.
• The wires from the light bulb are passed through a hole in the housing, and the wires from the phototransistor through a hole in the scale. A common tourniquet is placed in a vinyl chloride tube and fixed with a clamp. A 0.4 mm hole is drilled opposite the bulb.

• In addition to the sensor, the thermostat must have a voltage stabilizer. A photo relay is also required. The stabilizer is powered by a transformer. A modified transistor of the GT109 type serves as a photocell for the photorelay. All you need to do is remove the cap from its body and break off the base terminal.
• A mechanism made from a factory-made relay is used as a load. The work in this case follows the principle of an electromagnet, where the steel anchor goes inside the coil and affects the microswitch, which is fixed with 2 brackets. And the microswitch actuates the electromagnetic starter, through the contacts of which the supply voltage goes to the heating device.
• The photorelay, together with the power subunits, is placed in a housing made of insulating material. A thermometer is attached to it on a special rod. On the front side there is a neon light bulb (it will signal the start of work heating elements) and a toggle switch.
• In order for the regulator to work accurately, it is necessary to achieve a clear focusing of the light coming from the bulb onto the photocell.

How to make a thermostat with your own hands (video)

Thus, despite the complexity of the work, installing a thermostat greatly simplifies maintenance. Crops that receive an optimal microclimate develop better, which means that the harvest will be much larger.