Autonomous heating of a private house allows you to choose individual temperature modes, which is very comfortable and economical for residents. In order not to set a different mode in the room every time when the weather changes outside, you can use a thermostat or thermostat for heating, which can be installed on both radiators and the boiler.

Automatic regulation of heat in the room

What is it for

• The most common in the territory Russian Federation is an , on gas boilers. But such, if one may say so, luxury is not available in all regions and localities. The reasons for this are the most commonplace - the lack of a CHP or central boiler houses, as well as gas pipelines nearby.
• Have you ever been to a residential building, pumping station or weather station far from densely populated areas during the winter, when the only means of communication is a sled with a diesel engine? In such situations, they very often arrange heating with their own hands using electricity.

• For small rooms, for example, one attendant's room at a pumping station is enough - it is enough for the most severe winter, but for a larger area, a heating boiler and a radiator system will already be required. To maintain the desired temperature in the boiler, we bring to your attention a homemade regulator.

Temperature sensor

• This design does not require thermistors or various sensors type TSM, here instead of them a bipolar ordinary transistor is involved. Like everyone else semiconductor devices, its work largely depends on the environment, more precisely, on its temperature. As the temperature rises, the collector current increases, and this negatively affects the operation amplifier stage- the operating point shifts until the signal is distorted and the transistor simply does not respond to the input signal, that is, it stops working.

• Diodes are also semiconductors., and an increase in temperature has a negative effect on them as well. At t25⁰C, the "continuity" of a free silicon diode will show 700mV, and for a permanent one - about 300mV, but if the temperature rises, then the forward voltage of the device will correspondingly decrease. So, when the temperature rises by 1⁰C, the voltage will decrease by 2mV, that is, -2mV / 1⁰C.

• This dependence of semiconductor devices allows them to be used as temperature sensors. On such a negative cascade property with a fixed base current, the whole circuit of the thermostat operation is based (diagram in the photo above).
• The temperature sensor is mounted on a VT1 transistor of the KT835B type, the load of the stage is resistor R1, and the mode of operation for direct current of the transistor is set by resistors R2 and R3. To make the voltage across the transistor emitter at room temperature 6.8V, the fixed bias is set by the resistor R3.

Advice. For this reason, R 3 is marked with a * on the diagram, and you should not achieve special accuracy here, as long as there are no large drops. These measurements can be made with respect to a transistor collector connected by a power supply to a common drive.

• Transistor p-n-p KT835B specially selected, its collector is connected to a metal case plate with a hole for attaching the semiconductor to the radiator. It is for this hole that the device is attached to the plate to which the underwater wire is still attached.
• The assembled sensor is attached to the heating pipe using metal clamps, and the structure does not need to be insulated with any gasket from the heating pipe. The fact is that the collector is connected by one wire to the power source - this greatly simplifies the entire sensor and makes the contact better.

Comparator

• Comparator, mounted on the OP1 operational amplifier of the K140UD608 type, sets the temperature. The inverted input R5 is supplied with voltage from the emitter VT1, and through R6, the voltage from the engine R7 is supplied to the non-inverted input.
• This voltage determines the temperature to disconnect the load. The upper and lower ranges for setting the comparator threshold are set using R8 and R9. The required posteresis of the comparator operation is provided by R4.

Load management

• On VT2 and Rel1 made a load control device and the indicator of the operating mode of the thermostat is also here - red when heating, and green - reaching the required temperature. A diode VD1 is connected in parallel to the winding Rel1 to protect VT2 from the voltage caused by self-induction on the Rel1 coil when disconnected.

Advice. The figure above shows that the permissible switching current of the relay is 16A, which means that it allows the load to be controlled up to 3kW. Use a device with a power of 2-2.5kW to lighten the load.

Power Supply

• An arbitrary instruction allows for a real thermostat, in view of its low power, to use a cheap Chinese adapter as a power supply. You can also assemble a 12V rectifier yourself, with a circuit consumption current of no more than 200mA. For this purpose, a transformer with a power of up to 5W and an output from 15 to 17V will fit.
• The diode bridge is made on 1N4007 diodes, and the voltage regulator is based on an integral type 7812. Due to the low power, it is not required to install the stabilizer on the battery.

Adjusting the thermostat

• To check the sensor, you can use the most ordinary desk lamp with metal lampshade. As noted above, room temperature allows withstanding the voltage at the emitter VT1 of about 6.8V, but if you increase it to 90⁰C, then the voltage will drop to 5.99V. For measurements, you can use an ordinary Chinese multimeter with a DT838 thermocouple.
• The comparator works as follows: if the voltage of the temperature sensor at the inverting input is higher than the voltage at the non-inverting input, then at the output it will be equivalent to the voltage of the power supply - it will be a logical unit. Therefore VT2 opens and the relay turns on, moving the relay contacts to heating mode.
• Temperature sensor VT1 heats up as the heating circuit heats up and as the temperature rises, the voltage at the emitter decreases. At the moment when it drops slightly below the voltage that is set on the R7 engine, a logical zero is obtained, which leads to the transistor locking and the relay is turned off.
• At this time, the voltage is not supplied to the boiler and the system begins to cool down, which also entails the cooling of the VT1 sensor. This means that the voltage at the emitter rises and as soon as it crosses the border set by R7, the relay starts up again. This process will be repeated constantly.
• As you understand, the price of such a device is low, but it allows it to withstand the required temperature in any weather conditions. This is very convenient in cases where there are no permanent residents in the room who monitor the temperature regime, or when people are constantly replacing each other and, moreover, are busy with work.

Thermoregulators are widely used in modern household appliances, cars, heating and air conditioning systems, in manufacturing, in refrigeration equipment and during the operation of ovens. The principle of operation of any thermostat is based on turning on or off various devices after reaching certain temperature values.

Modern digital thermostats are controlled using buttons: touch or conventional. Many models are also equipped with a digital panel that displays the set temperature. The group of programmable thermostats is the most expensive. With the help of the device, you can provide for a change in temperature by the hour or set the required mode for a week in advance. The device can be controlled remotely: via a smartphone or computer.

For a complex technological process, for example, a steel-making furnace, making a thermostat with your own hands is a rather difficult task that requires serious knowledge. But collect small device for a cooler or incubator, any home craftsman can do it.

In order to understand how the temperature regulator works, consider a simple device that is used to open and close the damper of a mine boiler and is triggered when the air heats up.

For the operation of the device, 2 aluminum pipes, 2 levers, a return spring, a chain that goes to the boiler, and an adjusting unit in the form of a crane-axle box were used. All components were installed on the boiler.

As you know, the coefficient of linear thermal expansion of aluminum is 22x10-6 0С. When heating an aluminum pipe one and a half meters long, 0.02 m wide and 0.01 m thick to 130 degrees Celsius, an elongation of 4.29 mm occurs. When heated, the pipes expand, due to this, the levers are displaced, and the damper closes. When cooling down, the pipes decrease in length, and the levers open the damper. The main problem when using this circuit is that it is very difficult to accurately determine the response threshold of the thermostat. Today, preference is given to devices based on electronic components.

The scheme of work of a simple thermostat

Typically, relay-based circuits are used to maintain the set temperature. The main elements included in this equipment are:

• temperature sensor;
• threshold scheme;
• executive or indicator device.

Semiconductor elements, thermistors, resistance thermometers, thermocouples and bimetallic thermostats can be used as a sensor.

The thermostat circuit reacts to the excess of the parameter over the set level and turns on the executive device. The simplest version of such a device is a bipolar transistor element. The thermal relay is based on the Schmidt trigger. A thermistor acts as a temperature sensor - an element whose resistance changes depending on an increase or decrease in degrees.

R1 is a potentiometer that sets the initial offset on thermistor R2 and potentiometer R3. Due to the adjustment, the actuator is triggered and relay K1 is switched when the resistance of the thermistor changes. In this case, the operating voltage of the relay must correspond to the operating power supply of the equipment. To protect the output transistor from voltage surges, a semiconductor diode is connected in parallel. The load value of the connected element depends on the maximum current of the electromagnetic relay.

Attention! On the Internet, you can see pictures with drawings of a thermostat for various equipment. But quite often the picture and description do not match. Sometimes the pictures may simply represent other devices. Therefore, production can be started only after careful study of all the information.

Before starting work, you should decide on the power of the future thermostat and temperature range, in which he will work. The refrigerator will require some elements, and the heating will require others.

Thermostat on three elements

One of the elementary devices, by the example of which you can assemble and understand the principle of operation, is a simple do-it-yourself thermostat designed for a fan in a PC. All work is done on a breadboard. If there are problems with the pallet, then you can take a solderless board.

The thermostat circuit in this case consists of only three elements:

• power transistor MOSFET (N channel), you can use IRFZ24N MOSFET 12V and 10A or IFR510 Power MOSFET;
• potentiometer 10 kOhm;
• NTC thermistor 10 kOhm, which will act as a temperature sensor.

The temperature sensor reacts to an increase in degrees, due to which the whole circuit is triggered, and the fan turns on.

Now let's move on to setting up. To do this, turn on the computer and adjust the potentiometer, setting the value for the off fan. At the moment when the temperature approaches the critical one, we reduce the resistance as much as possible before the blades rotate very slowly. It is better to make the adjustment several times to make sure that the equipment is working efficiently.

The modern electronic industry offers elements and microcircuits that differ significantly in appearance and technical specifications... Each resistance or relay has several analogs. It is not necessary to use only those elements that are indicated in the diagram, you can take others that match the parameters with the samples.

Thermostats for heating boilers

When adjusting heating systems, it is important to accurately calibrate the device. This will require a voltage and current meter. To create a working system, you can use the following diagram.

Using this scheme, you can create outdoor equipment for controlling a solid fuel boiler. The role of the zener diode is performed by the K561LA7 microcircuit. The operation of the device is based on the ability of the thermistor to reduce resistance when heated. The resistor is connected to the electricity voltage divider network. The required temperature can be set using the variable resistor R2. The voltage is supplied to the 2I-NOT inverter. The resulting current is fed to the capacitor C1. A capacitor is connected to 2I-NOT, which controls the operation of one trigger. The latter is connected to the second trigger.

Temperature control goes according to the following scheme:

• with a decrease in degrees, the voltage in the relay increases;
• when a certain value is reached, the fan, which is connected to the relay, turns off.

It is better to solder on a mole rat. As a battery, you can take any device operating within 3-15 V.

Carefully! The installation of self-made devices for any purpose on heating systems can lead to equipment failure. Moreover, using similar devices may be prohibited at the level of services that supply communications in your home.

Digital thermostat

In order to create a fully functioning thermostat with accurate calibration, you cannot do without digital elements. Consider a device for controlling temperatures in a small vegetable store.

The main element here is the PIC16F628A microcontroller. This microcircuit provides control of various electronic devices... The PIC16F628A microcontroller contains 2 analog comparators, an internal oscillator, 3 timers, CCP comparison modules and USART data exchange.

When the thermostat is operating, the value of the existing and set temperature is fed to the MT30361 - a three-digit indicator with a common cathode. In order to set the required temperature, use the buttons: SB1 - to decrease and SB2 - to increase. If you carry out the setting while pressing the SB3 button, you can set the hysteresis values. The minimum hysteresis value for this circuit is 1 degree. A detailed drawing can be seen on the plan.

When creating any of the devices, it is important not only to properly solder the circuit itself, but also to think about how best to place the equipment. It is necessary that the board itself be protected from moisture and dust, otherwise a short circuit and failure cannot be avoided individual elements... Also, care should be taken to isolate all contacts.

Video

A simple electronic thermostat with your own hands. I propose a method for making a homemade thermostat to maintain a comfortable room temperature in cold weather. The thermostat allows switching power up to 3.6 kW. The most an important part any amateur radio design is a body. A beautiful and reliable case will ensure a long life for any homemade device. In the version of the thermostat shown below, a convenient small-sized case and all power electronics from an electronic timer sold in stores are used. The homemade electronic part is built on the LM311 comparator microcircuit.

Description of the operation of the circuit

The temperature sensor is a thermistor R1 with a nominal value of 150k, type MMT-1. Sensor R1 together with resistors R2, R3, R4 and R5 form a measuring bridge. Capacitors C1-C3 are installed to suppress interference. Variable resistor R3 balances the bridge, that is, sets the temperature.

If the temperature of the temperature sensor R1 drops below the set value, then its resistance will increase. The voltage at input 2 of the LM311 microcircuit will become more than at input 3. The comparator will work and at its output 4 it will be established high level, applied voltage to the timer electronic circuit through the HL1 LED will activate the relay and turn on the heating device. At the same time, the HL1 LED will light up, indicating that heating is on. Resistance R6 creates negative feedback between output 7 and input 2. This allows you to set hysteresis, that is, the heating turns on at a temperature lower than it turns off. Power to the board is supplied from the electronic timer circuit. Resistor R1 placed on the ground requires careful isolation, since the power supply of the thermostat is transformerless and does not have a galvanic isolation from the mains, that is dangerous mains voltage is present on the device components... The manufacturing procedure for the thermostat and how the thermistor is insulated is shown below.

How to make a thermostat with your own hands

1. The donor of the case and the power circuit is opened - the electronic timer CDT-1G. A timer microcontroller is installed on a gray three-wire cable. We unsolder the cable from the board. The openings for the loop wires are marked (+) - power supply +5 Volts, (O) - supply of a control signal, (-) - minus power supply. An electromagnetic relay will switch the load.

2. Since the power supply of the circuit from the power unit does not have a galvanic isolation from the mains, then all work on checking and setting up the circuit is carried out from a safe power source of 5 volts. First, at the stand, we check the operability of the circuit elements.

3. After checking the circuit elements, the structure is assembled on the board. The board for the device was not designed and is assembled on a piece of a breadboard. After assembly, a performance check is also carried out at the stand.

4. Thermal sensor R1 is installed outside on the side surface of the block-socket housing, the conductors are insulated with a heat-shrinkable tube. To prevent contact with the sensor, but also preserve the access of outside air to the sensor, a protective tube is installed on top. The tube is made from the middle part of a ballpoint pen. A hole has been cut in the tube for mounting on the sensor. The tube is glued to the body.

5. Variable resistor R3 is installed on the top cover of the case, there is also a hole for the LED. It is useful to cover the resistor case with a layer of electrical tape for safety.

6. The adjustment knob for the resistor R3 is homemade and made by hand from an old toothbrush of a suitable shape :).

Resistor R3

It is used in many technological processes, including for domestic heating systems. The factor that determines the action of the thermostat is the outside temperature, the value of which is analyzed and when the set limit is reached, the flow rate decreases or increases.

Thermostats come in various designs, and today there are many industrial versions on sale that work on different principles and are intended for use in different areas. The simplest are also available. electronic circuits, which can be collected by anyone, with the appropriate knowledge in electronics.

Description

A thermostat is a device installed in power supply systems that allows you to optimize energy consumption for heating. The main elements of the thermostat:

1. Temperature sensors- control the temperature level by generating electrical impulses of the appropriate magnitude.
2. Analytical unit- processes electrical signals received from sensors and converts the temperature value into a value characterizing the position of the actuator.
3. Executive agency- regulates the flow, by the value indicated by the analytical unit.

A modern thermostat is a microcircuit based on diodes, triodes or a zener diode that can convert heat energy into electrical energy. Both in industrial and home-made versions, this is a single unit to which a thermocouple is connected, remote or located here. The thermostat is connected in series to the electric power circuit of the executing organ, thus decreasing or increasing the value of the supply voltage.

Principle of operation

The temperature sensor generates electrical impulses, the current value of which depends on the temperature level. The built-in ratio of these values ​​allows the device to very accurately determine the temperature threshold and make a decision, for example, by how many degrees the air supply damper to the solid fuel boiler should be opened, or the hot water supply valve should be open. The essence of the thermostat is to convert one value to another and correlate the result with the current level.

Simple home-made regulators, as a rule, have a mechanical control in the form of a resistor, by moving which, the user sets the required temperature threshold for operation, that is, indicating at what outside temperature it will be necessary to increase the flow. With more advanced functionality, industrial devices can be programmed to wider limits, using a controller, depending on different temperature ranges. They have no mechanical controls, which contributes to long-term operation.

How to do it yourself

Self-made regulators are widely used in domestic conditions, especially since the necessary electronic parts and circuits can always be found. Heating the water in the aquarium, turning on the ventilation of the room when the temperature rises, and many other simple technological operations can be easily shifted to such automation.

Autoregulator circuits

Currently, among lovers of homemade electronics, two automatic control schemes are popular:

1. Based on an adjustable zener diode type TL431 - the principle of operation consists in fixing the excess of the voltage threshold of 2.5 volts. When it is broken on the control electrode, the zener diode comes to the open position and the load current passes through it. In the event that the voltage does not break through the 2.5 volt threshold, the circuit comes to the closed position and disconnects the load. The advantage of the circuit is its extreme simplicity and high reliability, since the Zener diode is equipped with only one input for supplying an adjustable voltage.
2. A thyristor microcircuit of the K561LA7 type, or its modern foreign analogue CD4011B - the main element is a T122 or KU202 thyristor, which acts as a powerful switching link. The current consumed by the circuit in normal mode does not exceed 5 mA, at a resistor temperature of 60 to 70 degrees. The transistor comes to an open position when pulses arrive, which in turn is a signal to open the thyristor. In the absence of a radiator, the latter acquires throughput up to 200 watts. To increase this threshold, you will need to install a more powerful thyristor, or equip an existing heatsink, which will bring the switching capacity to 1 kW.

Required materials and tools

Assembling on your own does not take much time, but you will definitely need some knowledge in the field of electronics and electrical engineering, as well as experience with a soldering iron. To work, you need the following:

• Impulse or ordinary soldering iron with a thin heating element.
• Printed circuit board.
• Solder and flux.
• Acid for etching tracks.
• Electronic parts according to the chosen scheme.

Thermostat circuit

Step by step guide

1. Electronic elements must be placed on the board in such a way that they can be easily mounted without touching the neighboring ones with the soldering iron, near the parts actively generating heat, the distance is made somewhat large.
2. The tracks between the elements are etched according to the drawing, if there is none, then a sketch on paper is preliminarily performed.
3. It is imperative to check the performance of each element and only after that the board is seated, followed by soldering to the tracks.
4. It is necessary to check the polarity of diodes, triodes and other parts in accordance with the diagram.
5. It is not recommended to use acid for soldering radio components, since it can short-circuit closely adjacent tracks; for isolation, rosin is added to the space between them.
6. After assembly, the device is adjusted by selecting the optimal resistor for the most accurate threshold for opening and closing the thyristor.

Scope of homemade thermostats

In everyday life, the use of a thermostat is most often found among summer residents operating home-made incubators and, as practice shows, they are no less effective than factory models. In fact, such a device can be used wherever it is necessary to perform some action depending on the temperature readings. Similarly, you can equip a lawn spraying or watering system with an automatic system, extending light-shielding structures, or simply sound or light alarms that warn of something.

DIY repair

Assembled with our own hands, these devices serve for a long time, however, there are several standard situations when repairs may be required:

• Failure of the regulating resistor - it happens most often, since the copper tracks wear out, inside the element along which the electrode slides is solved by replacing the part.
• Overheating of the thyristor or triode - the power has been incorrectly selected or the device is located in a poorly ventilated area of ​​the room. To avoid this in the future, thyristors are equipped with radiators, or the thermostat should be moved to an area with a neutral microclimate, which is especially important for wet rooms.
• Incorrect temperature adjustment - the thermistor may be damaged, corrosion or dirt on the measuring electrodes.

Advantages and disadvantages

Undoubtedly, the use of automatic regulation is already an advantage in itself, since the energy consumer gets the following opportunities:

• Energy saving.
• Constant comfortable room temperature.
• No human involvement required.

Automatic control is especially used in heating systems in apartment buildings. The inlet valves equipped with thermostats automatically control the supply of the heating medium, thanks to which residents receive significantly lower bills.

The disadvantage of such a device can be considered its cost, which, however, does not apply to those made by hand. Only industrial devices designed to regulate the supply of liquid and gaseous media are expensive, since the actuator includes a special motor and other shut-off valves.

Although the device itself is quite undemanding to the operating conditions, the accuracy of the response depends on the quality of the primary signal, and especially this applies to automation operating in conditions of high humidity or in contact with aggressive media. Thermal sensors in such cases should not come into direct contact with the coolant.

The leads are placed in a brass sleeve and sealed with epoxy glue. You can leave the end of the thermistor on the surface, which will contribute to greater sensitivity.

Thermostats are widely used for various purposes: in cars, heating systems different types, refrigerators and ovens. Their job is to turn off or turn on devices after reaching a certain temperature. It is not difficult to make a simple mechanical thermostat with your own hands. Modern designs have more complex scheme, but with some experience it is possible to make analogs of such devices.

Show all

Mechanical thermostat

Today, the newest models of thermostats are controlled using touch buttons, older models are mechanical. Most of these devices have a digital panel that displays the temperature of the coolant in real time, as well as the required maximum degree.

The production of such devices is not complete without their programming, so their price is very high. They allow you to customize temperature regime by various parameters, for example, by hours or days of the week. The temperature will change automatically.

If we talk about thermostats for industrial steel furnaces, it will be difficult to make them on your own, since they have a complex design and require the attention of more than one specialist. These are mainly manufactured in factories. But making a simple temperature controller with your own hands for an autonomous heating system, incubators, etc. is not a difficult task. The main thing is to adhere to all drawings and recommendations for production.

In order to understand how the thermostat works, a simple mechanical structure can be disassembled. It works on the principle of opening and closing the door (damper) of the boiler, which reduces or increases the access of air to the combustion chamber. The sensor reacts, of course, to temperature.

For the production of such a device you will need the following components:

• return spring;
• two levers;
• two aluminum tubes;
• an adjusting unit (looks like a crane-axle box);
• a chain that connects two parts (thermostat and door).

All components must be assembled and installed on the boiler.

The device works due to the property of aluminum to expand under the influence of temperature. In this regard, the flap closes. If the temperature decreases, the aluminum pipe cools down and shrinks, so the damper opens slightly.

But this scheme also has its significant disadvantages. The problem is that it is difficult to determine in this way when the damper will operate. To roughly tune the mechanism, precise calculations are needed. It is impossible to determine exactly how much the aluminum pipe will expand. Therefore, in most cases, devices with electronic sensors are now preferred.

Homemade mechanical thermostat for a mine boiler



Simple electronic device

For more accurate operation of the automatic temperature controller, electronic components are indispensable. The simplest thermostats work according to a relay-based scheme.





The main elements of such a device are:

• threshold scheme;
• indicator device;
• temperature sensor.

The circuit of a home-made thermostat should respond to an increase (decrease) in temperature and turn on the actuator or suspend its operation. To implement the simplest circuit, bipolar transistors should be used. The thermal relay is made according to the Schmidt trigger type. The thermistor will act as a temperature sensor. It will change the resistance depending on the temperature, which is set in the common control unit.

But in addition to the thermistor, the temperature sensor can be:

• thermistors;
• semiconductor elements;
• resistance thermometers;
• bimetallic relays;
• thermocouples.

When using diagrams and drawings from unknown sources, it should be borne in mind that they often do not correspond to the attached description. In this regard, it is necessary to carefully study all the material before proceeding with the manufacture of the device.

Before starting work, you need to decide on the temperature range of the device, as well as its power. It should be borne in mind that some components will be used for the refrigerator, and others for heating equipment.



Three-piece device

Simple electronic thermostat do it yourself can be assembled for use on fans and personal computers... Thus, you can understand how it works. A breadboard is used as a basis.

Of the tools, you will need a soldering iron, but if you don't have one or you don't have enough work experience, you can also use a solderless board.

The circuit consists of three elements:

• power transistor;
• potentiometer;
• a thermistor that will act as a temperature sensor.

The thermal sensor (thermistor) reacts to an increase in degrees, in connection with this, the fan will turn on.

To adjust the device, you must first set the data for the fan in the off position. Then you need to turn on the computer and wait until it heats up to a certain temperature in order to fix the moment the fan turns on. The setting is done several times. This will make sure that the work is effective.

Today, modern manufacturers of various elements and microcircuits can offer big choice spare parts. They all differ in technical characteristics and appearance.

DIY thermostat



Temperature regulators for heating systems

When manufacturing and installing a thermostat with a do-it-yourself air temperature sensor for heating systems, it is necessary to accurately calibrate the upper and lower line. This will avoid overheating of the equipment, which can lead to failure of the entire system at best. In the worst case, overheating of the equipment can lead to its explosion and possible death.




For these purposes, you will need a device to measure the current strength. With the help of drawings and diagrams, you can make external equipment for adjusting the temperature of a solid fuel boiler. For work, you can use the K561LA7 scheme. The principle of operation lies in the same ability of a thermistor to decrease or increase resistance under certain temperature conditions. The required indicators can be set using a resistor alternating current... First, the voltage is supplied to the inverter, and then it is transmitted to the capacitors, which are connected to the flip-flops and control their operation.

The principle of operation is simple. With decreasing degrees, the voltage in the relay increases. If the value is less than the lower limit values, the fan is automatically turned off.

It is better to solder the elements on a mole rat. As a power supply, you can use a device that operates in the range of 3-15 V.

Any home-made device installed on the heating system can lead to its failure. In addition, such actions may be prohibited by state control services. For example, if a gas boiler is installed in the house, then such additional equipment can be seized by the gas service. V individual cases even fines are issued.

Do-it-yourself thermostat for heating elements: diagram and instructions

Digital equipment

For the manufacture of a modern device with precise adjustment of the required degrees, digital components are indispensable.

PIC16F628A is used as the main microcircuit. With this scheme, you can control various devices electronic type.

The principle of operation is also not very complicated. The three-charge indicator with a common cathode is supplied with the values ​​of the set (required) temperature and the current one.

To set the desired temperature, the microcircuit has two elements sb1 and sb2, to which mechanical buttons are subsequently soldered. The first element serves to reduce the temperature, and the second to increase.

Setting the hysteresis value is performed by simultaneously pressing the sb3 button when setting.

When making homemade devices, it is important not only to properly solder and make a circuit, but also to place the device on the equipment in the right place. The board itself must be protected from moisture and dust in order to avoid a short circuit, and, accordingly, failure of the device. The isolation of all contacts is also very important.

Thermostats

Types of devices on the market

Today, companies that produce such equipment offer the buyer 3 main types of devices. They all work on different internal signals. It is their function that is to control the temperature and its equalization, depending on the settings of the device (upper and lower line).





There are three kinds of internal signals:

1. 1. Data is taken directly from the coolant. In everyday life, it is not very popular, since its effectiveness is insufficient. The principle of operation is a submersible sensor or other similar device. Although there are problems with efficiency, it belongs to the expensive segment of such devices on the market.
2. 2. Internal air waves. This option is the most popular because it is considered reliable and economical. It takes data not on the temperature of the coolant, but directly on the air. This allows for higher accuracy. What degree will be set in the control unit, such will be the air temperature. Connected to the heating system with a cable. Such models are constantly being improved by manufacturers, which makes them more convenient and functional.
3. 3. External air waves. Operates on the basis of an outdoor sensor. It works under any changes in weather conditions, and immediately reacts by changing the settings of the heating equipment.

Such devices can be both electrical and electronic. The thermostats can receive a signal in automatic or semi-automatic mode. The work and temperature change can occur due to the control over the temperature of the radiators and the main lines or by recording changes in the boiler power.

Today there are many popular models from top manufacturers who have already secured their position. These include, first of all, E 51.716 and IWarm 710. The case itself is small and made of plastpolymer, which does not burn. Despite this, there are many useful functions... The display, as for such small sizes, is quite large. It displays all existing data. Such devices cost in the range of 2500-3000 rubles.

TO functional features the first model can be attributed to the possibility of its installation into the wall in any position, the temperature is controlled simultaneously from the floor itself, as well as the presence of a 3 m cable.When installing, you need to think about whether there will be free access to the device for unhindered control.

To the above pluses, you can add some minuses. These include a small set of functions that are in the analogs of these devices. It sometimes causes discomfort when used. In addition, these models do not have an automatic heating function. But if you wish, you can finish it yourself.

Thus, making your own thermostat or purchasing and installing a ready-made model will not be difficult if you adhere exactly to all the diagrams, drawings and instructions for manufacturing and installation. This equipment will save the owners time on manual temperature control of certain devices.