Room thermostat for gas boiler from Aliexpress from China

Thermostats for heating equipment belong to the category of devices designed to maintain a constant temperature regime. Many users of modern gas boilers and others use exclusively the factory functionality, which allows them to set the desired temperature. However, in some cases, it is the use of a thermostat that helps ensure maximum living comfort.

Choosing a programmable room thermostat for a gas boiler on Aliexpress

Why do you need a room thermostat?

Installing a room thermostat in the house and connecting it to a gas boiler solves two problems:

Provides a comfortable air temperature in the house. Eliminates situations when you want to “turn up the heating” because the rooms are hot, or vice versa, “turn up the heat” because it’s cold.
Significantly reduces gas consumption for heating , as it allows you to avoid “overheating” in the house - keeping many rooms at a lower temperature. A change in room temperature of just 1 °C leads to an increase or saving in the amount of gas for heating by approximately 4-5%.

In rarely visited areas of the house, it is beneficial to keep the temperature lower. Building regulations recommend maintaining the air temperature in different rooms of the house during the heating period in the range from +12 to +26 °C.

Standards for air temperature in residential areas of the house

In a private house or apartment, when setting up the heating system, it is recommended to focus on the indoor air temperature standards established by GOST 30494-2011. Interstate standard. Residential and public buildings. Indoor microclimate parameters":

The name of a room	Temperature (оС), optimal / permissible
Living room	20-22 / 18-24
The same, but in areas where the outside air temperature of the coldest five-day period is -31 °C or lower	21-23 / 20-24
Kitchen, toilet	19-21 / 18-26
Bathroom, combined toilet	24-26 / 18-26
Staircase, lobby	16-18 / 14-22
Pantry	16-18 / 12-22

A room regulator allows you to maintain a constant temperature in a heated room with high accuracy. With manual control, the range of temperature fluctuations is larger and deviations are more often towards higher temperatures. Every extra degree in the room leads to an increase in gas consumption for heating . In addition, using a thermostat, you can program an automatic decrease in the temperature in the house during certain periods (at night...).

In rich EU countries, the room temperature set at night usually does not exceed 16-17 degrees. This is evidenced by a report presented by the German thermostat manufacturer Tado for 2014.

Room thermostat saves energy

When the boiler operates without a room thermostat, the circulation pump runs constantly, consuming electricity. The circulation pump, controlled by a two-position room thermostat, operates intermittently, which saves energy and the life of the pump.

General principles for connecting a thermostat

The method and diagrams for connecting the thermostat to the heating equipment itself can be found in the technical data sheet of the gas boiler. Modern equipment, regardless of manufacturer, requires connection points for the thermostat. The connection is made using the terminals on the boiler or the thermostat cable included in the delivery package.

If you are using a wireless thermostat, place the measuring unit only in a residential area. This may be the coldest room or the room where the largest number of people often gathers, the children's room.

It is not advisable to install a thermostat unit in the kitchen, hall or boiler room, where the temperature regime is unstable.

The thermostat should not be exposed to sunlight, it should not be located in a draft, near heating devices and electrical equipment that emit a large amount of heat - thermal interference has a bad effect on the operation of the device

Connecting different types and models of thermostats may have their own characteristics; installation is carried out in accordance with the manufacturer's instructions, which are included with the device.

Recommendations include a comprehensive description of the regulator's operation, connection method and diagrams. Next, we will tell you how to properly connect a thermostat to a gas boiler and about the installation features of the most typical regulator models.

Connecting a mechanical thermostat

The mechanical type thermostat is distinguished by its reliability and simplicity of design, low cost, and long-term operation.

However, it supports only one temperature mode, which is set by changing the position of the handle on the temperature scale mark. Most thermostats operate in the temperature range from 10 to 30°C.

To connect a mechanical thermostat to an air conditioner, use the NC terminal; to gas or any other heating equipment, use the NO terminal

The mechanical thermostat has the simplest principle of operation and is activated through an opening and breaking circuit, which occurs using a bimetallic strip. The thermostat is connected to the boiler through the terminal box on the boiler control board.

When connecting the thermostat, pay attention to the markings - they are present on almost all models. If there are no markings, use a tester: pressing one probe to the middle terminal, check the side terminals with the second and identify a pair of open contacts

Installation of an electronic thermostat

The design of an electronic thermostat requires the presence of an electronic board that is responsible for controlling the device.

The control signal is potential - voltage is transmitted to the boiler input, which leads to the closing or opening of the contact. A voltage of 220 or 24 volts must be supplied to the thermostat.

Electronic thermostats allow for more complex settings of the heating system. When connecting an electronic thermostat, the power wire and neutral are connected to it. The device transmits voltage to the boiler input, which starts the operation of the equipment

An electronically controlled thermostat is used to organize the operation of complex climate systems. It will help in controlling not only an atmospheric or turbine gas boiler, but also a pump, air conditioner, and servo drive in the heating system.

How to connect a wireless thermostat?

The wireless thermostat consists of two blocks, one of which is installed in a living room and acts as a transmitter. The second unit is mounted near the heating boiler and connected to its valve or controller.

Data transmission from one block to another is carried out over a radio channel. To control the device, the control unit is equipped with an LCD display and a small keyboard. To connect the thermostat, set the sensor address and install the unit at a point with a stable signal.

Thermostat connection diagram for an open circuit - the equipment turns on at the moment the current appears. A similar circuit is used when connecting a mechanical thermostat

The main disadvantage of a wireless thermostat is that the remote unit is powered by batteries, which have a limited resource and therefore require frequent replacement. To ensure uninterrupted operation, the device is equipped with an alarm function that warns when the battery needs to be replaced.

Which room thermostat should you choose?

We select a room thermostat based on the following basic and mandatory requirements for the thermostat:

The boiler control principle is two-position with On/Off contacts. This thermostat is cheaper and fits any gas boiler.
The temperature control algorithm is programmable , automatically changing the room temperature settings throughout the day, at least at night.
Connection to the boiler is by wires. It's cheaper and easier. A gas boiler is installed in the kitchen of the house. Connecting a room thermostat to the boiler with wires does not cause problems, especially if it is done at the stage of finishing or repairing premises.
With temperature control by hysteresis. The hysteresis value is no more than +/- 0.5 °C. Hysteresis is the amount of deviation of the thermostat response temperature for turning the boiler on and off from the set temperature. The room temperature will change by an amount greater than the hysteresis, approximately +/- 1 °C.

On-off thermostats for gas boilers have a relay output with “dry” contacts on which there is no electrical voltage . The power sources for such thermostats are usually galvanic batteries or accumulators.

Don't go wrong with your choice. Don't buy a powered thermostat. The relay contacts of such a thermostat will most likely be under mains voltage. They are intended for other purposes.

The thermostat relay contacts can be in one of two positions: closed or open. Connected to the boiler, closed thermostat contacts activate the boiler heating mode . When the contacts open, the heating mode is switched off. The boiler operates in cycles - on/off. There are no changes in the heating mode settings on the boiler itself.

Another important parameter to choose is the temperature control algorithm. Thermostats available:

With temperature control by hysteresis (proportional control algorithm);
With PI control (proportional - integral algorithm).
With switching control algorithms. You can manually select the first or second.

Thermostats with PI control have advantages. They provide more accurate maintenance of indoor air temperature +/- 0.5 °C. The temperature of the heating water, and therefore the radiators, changes to a lesser extent during the regulation process.

Disadvantages of thermostats with PI regulation. More frequent switching on and off of boilers. The boiler, controlled by a thermostat with PI regulation, operates in cycles of 10 - 20 minutes. At the beginning of the cycle, the boiler turns on, after a few minutes of operation it turns off and waits for the next cycle to begin. Temperature regulation occurs by changing the duration of the boiler operation in the cycle.

The choice in favor of a room thermostat with hysteresis control was made due to their lower cost and availability on the AliExpress trading platform.

How to set up a boiler yourself

Why do you need proper adjustment of equipment:

To save resources.
To make the room comfortable, use hot water.
To extend the life of the equipment.

You need to start with the right choice of boiler and its power. Consider the features of the room: the number and area of windows, doors, quality of insulation, wall materials. The minimum calculation is based on heat losses per unit time. You will learn more about this in the article “How to calculate the power of a gas boiler.”

Gas boilers are divided into single-circuit and double-circuit. The latter perform heating on the heating and hot water supply (DHW) circuit. Single-circuit units provide heating only. Therefore, to obtain hot water, indirect heating boilers are installed.

Depending on the type of placement, equipment can be floor-mounted or wall-mounted. Units placed on the floor have greater power. Therefore, they are used for large areas (from 300 m²). Installation is carried out only in separate rooms (boiler rooms). These are models Baxi (“Baksi”), Buderus (“Buderus”), “Navien”, “Kiturami”.

Attachment appliances (Neva Lux, Arderia, Daewoo, Ariston, Bosch) fit perfectly in small apartments in the kitchen. Therefore, it is important to take into account all the nuances of the location. The comfort of residents, as well as the durability of the boiler, depend on the correct selection of parameters.

Power setting

The heating power depends on the modulation of the gas burner. If you choose an electronically controlled device, then it includes a thermostat that connects to a room thermometer. The adjustment occurs automatically: the thermometer measures the temperature in the room. As soon as it drops below a comfortable level, he gives a command to start the burner or increase the flame power.

In normal mode, the thermometer monitors the temperature in only one room. But if you install valves in front of each radiator, control will be in all rooms.

You can adjust the burner manually by operating the gas valve. This is true for atmospheric boilers with an open combustion chamber. Thus, in the Protherm “Cheetah” and “Protherm Bear” models, the valve is controlled by an electric motor. To change the settings, you need to go to the service menu. Most often, this is done by a specialist, and the user follows the steps specified in the instructions.

But we will still tell you how to call up the hidden menu for adjustments.

Before going into the menu and making settings, do this:

Unscrew the taps on the batteries.
Set the room thermostat to maximum values.
In the user settings, set the maximum temperature that you use in severe frosts. The burner always turns off when the readings reach 5°C above the set values. For example, at +75 degrees, a shutdown will occur when it reaches 80 degrees.
Cool the coolant to 30°C.

Choosing a room thermostat on Aliexpress from China

At first glance, the AliExpress trading platform offers many models of room thermostats for a gas boiler. But, after careful study, you understand that most models are analogues under different brands.

I considered two options: a model with control buttons on the body and with touch buttons on the screen. The choice was made in favor of the buttons on the case. You won't have to use the buttons often. It's more convenient and cheaper.

Room thermostat from Aliexpress from China, model BGL02-5BB, is an electronic two-position programmable controller that allows you to adjust the temperature according to one weekly program with the possibility of combinations of six different time intervals.

The thermostat, model BGL02-5BB, supports the function of protecting the heating system from freezing when the room temperature drops to 5 °C.

The amount of hysteresis can be set in the settings. The minimum hysteresis value is +/- 0.5 °C.

The body of the device is made of high-quality plastic with a glossy surface. The printed circuit board looks neat, covered with protective transparent plastic on top.

The parcel was delivered by Chinese and Russian mail 18 days after payment for the order.

Cons, disadvantages of a thermostat with Aliexpress

There is no function for monitoring the discharge of the 1.5 V battery, AA 2 pcs. I didn’t pay attention to this when choosing the device. It's my own fault. Although the batteries last for more than a year of operation. I change them before the start of the heating season - no problem.

When you manipulate the buttons, the screen backlight turns on. If the screen is located above eye level, the image on the screen becomes difficult to see. Place the device on the wall as expected, at a height of 1.5 m. If you look at the illuminated screen from top to bottom, then everything is clearly visible.

The box with the thermostat contains one sheet of instructions in English. The instructions do not contain any indication of the model or brand of thermostat. The contents of the instructions in some points do not correspond to the thermostat model.

Complaints about the instructions not matching the device model are often found in customer reviews on AliExpress.

Products for construction and repair

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Connecting a room thermostat to a Protherm gas boiler

The wires from the room thermostat - thermostat are connected to the terminal block marked as X17 (black in the figure on the left) in the 24 V compartment of the control panel of the Protherm Gepard (Panther) gas boiler.

The wires from the contacts of the on-off thermostat relay are connected on the block to the RT . The terminals will be shorted with a jumper wire that must be removed.

Terminal block for room thermostat from Aliexpress. The two-core wire from the gas boiler is connected to the terminals designated COM and NO. It does not matter which wire core is connected to which terminal.

Connecting a room thermostat to other models of gas boilers is done in the same way. You just need to find the location of the corresponding terminal block on the boiler.

How does a gas boiler room thermostat work?

A protective film is visible on the thermostat display.
The current room temperature and the temperature set by the setting are displayed. Sun - work in a programmable mode in the “Sunday afternoon” interval. Snowflake - Frost protection function is enabled. At the bottom of the screen is the current time and day of the week - Sunday. installed in the room , with temperature control by hysteresis , measures the current air temperature and, if the temperature drops from the value set in the settings, turns the boiler on. For example, if the temperature is set to 22 °C in the thermostat setting, then the boiler will turn on, taking into account the hysteresis +/- 0.5 °C, when the air temperature drops to 21.5 °C. The heating water heated by the boiler will begin to flow into the radiators and heat them. The radiators, in turn, will heat the air in the room.

The problem is that the process of heat transfer from radiators to the room air is very slow. After turning on the boiler, the air temperature in the room, at the place where the thermostat is installed, will continue to decrease for some time, to 21 °C, and only after that will begin to increase. When the air temperature increases to 22.5 °C, the thermostat will turn off the boiler. But from the heated radiators, the air temperature in the room will continue to increase for some time, up to 23 ° C.

Due to the presence of a large time delay in the feedback loop, fluctuations in the air temperature in the room will be noticeably greater than the value of the thermostat hysteresis. Fluctuations in the air temperature in the room will be +/- 1 °C from the specified 22 °C.

Often the temperature of the heating water manages to increase to the maximum at which the boiler will disconnect from the boiler temperature sensor. Although the thermostat will still command the boiler to turn on.

Device and technical characteristics

The peculiarity of the KChM-5 boiler is that its heat exchanger is not solid, like most heating devices, but consists of cast iron sections. The number of sections increases with increasing power.

Photo 1: Hot-water solid fuel household boiler KCHM-5

The next feature of KChM heating devices is their versatility. If necessary, a solid fuel boiler can be easily converted to operate on gas, diesel fuel, fuel oil, or exhaust gas. If you install a pellet burner and a hopper with a feed auger, the KChM-5 easily turns into an automatic long-burning pellet boiler. You just need to slightly modify it, install a burner for the appropriate fuel, and now it’s gas or diesel. This versatility can be very useful if main gas is still being installed, but a heating device is needed now. Then everything is simple, install a solid fuel boiler KChM-5, and then switch it to gas with a minimum of costs.

Photo 2: Heating boiler KChM-5 with Baxi gas burner

Let's take a closer look at what parts the KChM-5 boiler consists of:

We have already mentioned that the heat exchanger consists of sections. At the bottom of the near section there is a pipe for connecting the return line of the heating system, and at the top of the far section there is a pipe for connecting the direct line.
There are three doors on the front panel: the loading door, the scooping door and the ash pan door. The loading chamber has holes for access of secondary air. By adjusting the amount of opening of the ash pan door, you can regulate the intensity of combustion. This process is performed either manually using an adjusting screw or using a draft regulator.
On the rear wall of the boiler there is a chimney pipe with a smoke damper. Thanks to it, you can regulate the output of combustion products.
The entire body of the KChM-5 is insulated with a special material to prevent heat loss and increase operating efficiency. The outside of the body is coated with wear-resistant paint.
To prevent boiling and control the water temperature in the heating system, a thermometer is provided. It measures the water temperature in the middle section and displays the readings on the front panel.

Setting the boiler thermostat

Since the instructions for the thermostat purchased on Aliexpress are in English and do not correspond to the device, I had to find a video on setting up a room thermostat. The device in the video and its functions are exactly the same, although the model is called differently.

I recommend setting the hysteresis value in the settings , function dIF =0.5 .

Entering the service settings menu: with the device turned off, hold down the “down” button and press the “on” button. The designation of the first menu item, the dIF function, appears on the screen, and the numbers flashing, indicating its value. Using the “down” button we set a new value =0.5.

To save gas, I highly recommend setting the thermostat to weekly temperature programming.

The table shows the factory thermostat temperature settings for a weekly program with a combination of six different time periods. On working days: 1 - morning at home; 2 - went to work; 3 - came for lunch; 4 - left for work after lunch; 5 - came home from work, evening at home; 6 - night in a warm bed. Temperature and time can be changed in the settings at your discretion.

Taking into account the presence of pensioners in the house, I set the temperature in the program settings to 24 °C during the daytime, and 20 °C at night, on all days of the week. According to the control thermometer, the air temperature in the room where the thermostat is located is maintained with an accuracy of +/- 1 °C. Within 23-25 oC during the day, and 19-21 oC at night.

Previously, the gas boiler operated under the control of a room thermostat with PI control. Air temperature fluctuations were two times less.

Entering the programming settings menu: hold the “M” button until “LooP” appears on the screen.

Next, use the “up” and “down” buttons to select working days “1 2 3 4 5” or working days with Saturday “1 2 3 4 5 6” or all days of the week “1 2 3 4 5 6 7”. If not all days of the week are selected at this stage, then to select the remaining days of the week, press the “M” button repeatedly until the designations of the remaining days appear on the screen: “6 7” (if “1 2 3 4 5” were selected at the first stage ) or “7” (if “1 2 3 4 5 6” were selected at the first stage).

Then, using the “M” button, select the period of the day. In the selected period, the numbers indicating the temperature flash. Use the “up” and “down” buttons to set the temperature. Use the “clock”, “up”, “down” buttons to set the start time of the period. Use the “M” button to move to the next period.

Types of control devices

Thermostats for heating boilers with the option of temperature control are divided into several types:

mechanical models with one function;
programmable models with a large range of auxiliary settings.

Wireless models
Also, similar designs are wireless and wired. Thermostats are installed in the selected location, a temperature sensor is connected and connected to the control device.

Design diagram of the control device

Note! Thermostats must be provided with constant air access to prevent overheating. It is also not recommended to install electrical appliances nearby.

Selecting a room programmable device

The option of an electronic temperature sensor for a heating boiler helps you select the appropriate temperature mode and change it at your discretion. The room thermostat sets the set values every day. Some setpoint values can be programmed, for example when day turns to night.

Such controllers have additional options. For example, a function that allows you to stop heating for a while and then resume it. You can also change the programmable temperatures for the duration of the configured periods. Another useful option is the ability to change the heating intensity.

Room type regulator

Thermostat as a central element

The central thermostat for the heating boiler (temperature regulator) is located at a certain distance from the heating unit and allows you to turn off and turn on equipment throughout the house.

Installation diagram of thermostats in the heating system

Thermostat for heating radiator. What task does this device perform and what is its advantage? What is the operating principle and correct installation? Prices also matter. More details in a special publication.

Models from previous years are connected directly to the heating unit by wires, while more modern designs are distinguished by remote control. The latest devices are mounted in dual-circuit units Beretta, Ferroli and AOGV. Room control mechanisms for boilers of the Protherm and Gsm brands are popular. They differ in their dilatometric mechanism.

Protherm equipment models

Room devices stop heating when necessary. They monitor the air temperature and turn on the heating when the temperature drops. The best place for a microcontroller is considered to be the bedroom and living room.

Installing a controller will allow you to obtain accurate data on the microclimate of the room

Helpful information! The recommended temperature for the thermostat is 20 degrees, and in the children's room - 21-22 degrees. At night, the temperature can vary from 19 to 21 degrees.

Thermostatic valves for regulation

Such a device allows you to create a certain coolant temperature by mixing the forward and return flows. The device helps control temperature values by changing the flow of hot water through the battery. In this case, the mechanism controls the supply of hot water through the battery, but not through the boiler. It is installed in any room where you need to maintain a certain temperature.

Thermostatic valve design using the example of a specific model

Setting up the heating system under the control of a room thermostat

On a gas boiler controlled by a two-position thermostat, the heating water temperature setting must be set to maximum. The same as it was installed in winter in the coldest weather (65 ° C).

It is advantageous to install a room thermostat that controls the operation of the boiler in the largest room of the house. Radiators in the room in which the thermostat is installed should not have automatic valves that regulate coolant flow.

In other rooms, I recommend installing a thermostatic valve on each radiator , which regulates the coolant flow through the radiator depending on the temperature in the room. This will avoid overheating and keep the air temperature in the house lower but comfortable.

Read more: How to reduce the high gas consumption of a boiler for heating a house.

Models

Let's take a closer look at the features and technical characteristics of the most popular models of KChM Micro and KChM-5 boilers.

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Each of these models is designed for use in local heating systems for small rooms. The equipment includes a regulator for the flow of air masses into the combustion chamber, so you can regulate the intensity of the boiler operation based on what temperature will be acceptable in a particular room.

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All modifications are made in accordance with the requirements of permitting services and meet sanitary standards. The materials used to make the devices do not pose any danger to human health.

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The thermal insulation of the casing is made of polymers that tolerate high temperatures well and do not emit any harmful substances. With such thermal insulation, the devices are absolutely safe, because the surface of the unit does not heat up to high temperatures. They are also very efficient at work.

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The unit operating on solid fuel KChM-5 is in wide user demand. In terms of quality and reliability, the device is in no way inferior to its European analogues, despite the fact that its price is half as much. The boiler can operate on different types of fuel. The simplest models operate on solid fuel, and if special burners are additionally installed, the devices can operate on gas and diesel fuel.

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Solid fuel boiler KChM-5 30 kW 4 sections

The simplest model is single-circuit, i.e. it can only be used to supply heat to the house. However, the manufacturer provides the opportunity to use a heat generator to provide hot water in the house.

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The heat exchanger of KChM 5 is constructed of cast iron sections, the number of which varies from 3 to 9, it all depends on the specific model. Based on the number of sections, the technical characteristics of the device also vary: power, size, volume of the combustion chamber:

dimensions: 500*715*1150 mm;
firebox volume - 35 l;
power - 21 kW (if anthracite is used);
heating area reaches 210 m²;
coal consumption is 3.3 km/h;
productivity is quite high, approximately 80%.

Key advantages of the heating boiler KCHM-5:

The model is universal; you can improve it at any time by installing an additional burner.
All working elements are made of high-quality materials, due to which the unit is characterized by a long service life.
The devices are extremely simple to maintain and maintain.
Good combustion performance is ensured at any draft parameters, which is why there will always be a comfortable temperature in the house, no matter what the weather is like outside.

Model KChM-5 is a long-burning heating device. This means you won't have to refill fuel too often. This operating principle is very convenient, because not all owners of private houses will be able to constantly monitor the operation of the unit. The Kirov boiler KChM-5 includes a thermostat, thanks to which you can maintain the temperature of the coolant at the desired level.

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KChM Micro

This unit is used for heating rooms with an area of 140-170 m². The devices operate on solid fuel, but if necessary, you can switch them to gas.

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In order to convert the boiler you need to buy a special atmospheric burner and an automation unit.

The unit received its name because of its compact size. There are KChM Micro boilers on the market with 4 and 5 sections.

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Solid fuel boiler KChM MICRO

length - 630 mm;
height - 805 mm;
width - 400 mm;
the volume of the combustion chamber is 29 l (if we are talking about devices with four sections) and 41 l (with five sections).

The boiler is absolutely unpretentious to the quality of the coolant; both water and antifreeze can be used. The water is heated to 95°C, the pressure in the system does not exceed 0.4 MPa.

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The power of the device is directly dependent on what fuel is used. If you purchased a model with 4 sections, then the boiler power when burning anthracite will be 14 kW, and when burning wood - 11 kW. Equipment productivity is 78-80%, fuel burns at a temperature of 350° C.

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