By installing an automatic temperature controller, the user hopes to save energy that is spent on heating an apartment or a private house. True, the purchase and installation of the device sometimes gives the opposite result - the consumption of gas or electricity increases. Therefore, we offer to clarify a number of points: how a room thermostat for a gas boiler works, types of temperature controllers, connection methods and proper settings.
Briefly about the principle of work
For a better understanding of the operating principle of room thermostats, we first explain the algorithm of the boiler as standard:
- The user ignites the heater, using the buttons or control knobs sets the desired temperature of the coolant.
- Each unit is equipped with an immersion or surface-mounted sensor, informing the control unit of the degree of water heating. When the temperature of the coolant reaches a predetermined threshold, the gas valve is activated and shuts off the fuel supply to the main burner. The circulation pump continues to “drive” water through the system.
- After the coolant has cooled to the lower temperature limit, the gas supply resumes, the burner again ignites and heats the water.
Reference. In turbocharged wood-fired boilers, the automation switches off the blower-fan. Air intake and the combustion process in the furnace are suspended, the unit goes into standby mode.
Without an external temperature sensor, the heater “does not see” the air temperature in the rooms and bluntly heats the water to the specified limit. Result: in the transitional autumn-spring period, the so-called timing is observed - a frequent start / stop of the burner (once every 2-3 minutes), reducing the aggregate resource as a whole.
Now about the main thing. The remote temperature controller extends the intervals between turning on / off the gas boiler, since it focuses on the temperature of the air, which cools more slowly. The device is included in the open circuit of the power supply of the gas valve (on TT-boilers - turbines) and the built-in pump.
Installing an automatic temperature controller allows you to kill three birds with one stone:
- reduce energy consumption;
- make boiler control more convenient;
- extend the life of the heat source.
Important notice. The items listed do not apply only to gas heaters. Any heat generator equipped with an electronic or electric control unit is connected to the thermostat: solid fuel, diesel, electric boiler, and so on.
When the room warms up to the indicated temperature, the thermostat breaks the circuit, the burner and the integrated heat generator pump stop. The unit starts after cooling the air by 1-2 degrees, which increases the duration of the interval between shutdown and ignition to 15-20 minutes.
Note 2 significant nuances:
- When using the room controller, the standard start / stop function for the temperature of the water in the boiler jacket continues to operate. When the coolant in the boiler heats up to the set limit, the gas burner will turn off.
- If the burner is extinguished by the command of the internal temperature sensor, the standard circulation pump continues to work. When the external thermostat is triggered, both devices — the burner and the pump unit — stop.
That is why it is important to properly configure the boiler bundle - an external thermostat.
Types of room controllers
For automatic adjustment of the boiler combustion according to the room temperature, 2 types of thermostats are used:
- Mechanical.The circuit is opened and closed by a bimetallic plate bending from heating. To change the desired temperature, the user rotates the handle, which increases or decreases the gap between the plate and the second contact.
- Electronic (digital). Here, the role of a heat-sensitive element is played by a thermistor, which changes the resistance depending on the temperature. The circuit where this part enters closes the relay contacts, guided by the change in resistance and user settings.
Reference. Mechanical and electronic thermal sensors are used not only for the boiler. Thermostats are successfully used in other parts of the heating system, for example, to turn off the circulation pump of a separate radiator branch or for zone control of warm floors.
The mechanical device is connected to the heat generator through a cable. Most electronic models provide wireless connectivity. According to reviews, radio-controlled thermostats are gaining wide popularity due to the convenience of installation and operation. How the wireless boiler temperature regulator works:
- The device consists of two units equipped with radio modules.
- The first block, including the executive relay, is installed directly next to the heater and connected to the desired connector. Food - from the house electric network of 220 volts.
- The second unit with a display and control buttons is powered by batteries and installed in a convenient place in the home.
- The temperature sensor located inside the remote control reacts to the air temperature. At the right time, the radio module sends signals to the first unit on the inclusion / stop of the boiler. He opens the relay contacts, heating and circulation of the coolant stops or resumes.
Typically, electronic models are equipped with programmers that allow you to set the schedule of the boiler for a week. The temperature in the rooms can be changed several times during the day. Individual instances are programmed for 90 days and controlled via mobile communications, for example, via SMS or the smartphone’s Internet application.
Which thermostat is better to choose
To make the right choice of a room controller, we suggest considering the pros and cons of two types of household appliances. The disadvantages of mechanical models:
- low accuracy of the maintained temperature;
- wired connection - the cable will have to be pulled from the boiler room to the desired room;
- lack of various convenient functions available in programmers.
Note. Judging by the reviews of the real owners on the forums, the accuracy of maintaining the temperature is not a critical problem and does not worry users too much. Another thing is the wires that need to be hidden under the baseboards, in the furrows of the walls, and so on.
There are three obvious advantages of bimetallic thermostats:
- low price and availability;
- reliability in work - in the simplest models there is nothing to break;
- simplicity of controlling the boiler with a single handle, which is important for elderly homeowners.
The negative sides of electronic regulators are the higher price, the interface is not always clear and the need for timely battery replacement. Cheap Chinese models have an additional problem - communication failure with the relay unit when installing the control panel behind 1-2 partitions.
An absolute plus of digital temperature controllers is comfortable operation. It is enough to lay once a weekly and daily program of work of the heat generator, no further action will be required.
We list a typical set of functions using the Baxi Magic Plus thermostat as an example:
- temperature control range - 5 ... 35 ° С;
- protection against freezing of the heating system, by default it starts the boiler when the home cools down to +3 degrees;
- LCD with backlight, control - push-button;
- a shift in the temperature sensor ± 5 ° C (for an explanation, see the next section of the publication);
- 2 operating modes - economical and comfortable;
- hourly / daily / weekly programmer.
Reference. Manufacturers often call such devices digital chronothermostats. The weak point of the devices is low maintainability in the event of a breakdown, especially of Chinese products, for which it is not easy to find spare parts.
Knowing the features of electronic and mechanical regulators, it is not difficult to choose a suitable model. Focusing on your budget, first of all, consider reliable products of European, Japanese and Korean manufacturers. Among the "Chinese" there are also decent brands, but on average the product quality leaves much to be desired.
Installation and connection of the device
The installation of the household regulator consists of two stages - mounting in a convenient place and connecting to a gas (solid fuel) boiler. In order for the thermostat to fix the temperature without deviations, position the control element according to the recommendations:
- minimum height from the floor - 1.5 m, maximum - 1.7 m;
- within 1 m from the appliance there should be no radiators, heaters or other household appliances that distort the thermal picture (including air conditioners);
- exclude exposure to drafts, working ventilation;
- it is undesirable to place the sensor away from heated rooms.
Tip. For a private house with warm floors, it is worth buying a thermostat model, equipped with an additional temperature sensor. The latter is located above the floor surface and measures the temperature in the lower zone of the room.
After mounting the device on the wall, according to the manufacturer's instructions, lay the wire to the heat source in a hidden or open way (if there is a wired connection). How to connect the regulator to the boiler:
- Connect one end of the control cable to the terminals marked COM (common) and NO (normally open) of the thermostat. On a wireless modification, these terminals are located in the relay box.
- In the operating instructions for the heat generator, find the connection scheme of the remote thermostat, marking and location of the contacts.
- Remove or swing down the front panel of the gas heater blocking access to the control board and connectors.
- Remove the jumper inserted between the terminals indicated in the passport. Do not discard the part; later it may be needed.
- Connect the wires coming from the regulator contacts to the released terminals. It is not necessary to observe the polarity.
- When installing the wireless thermostat, connect a three-wire 220 V power cable with a ground wire to the relay unit.
Tip. If the contacts of your device have numbers or incomprehensible letters instead of the indicated marking, look for the 2 necessary terminals with the help of a tester (the circuit between them must be open). There are three contacts in total; a pair of COM and NC is initially closed, as shown above in the diagram.
Non-volatile floor boilers equipped with gas automation 630 SIT, 710 MiniSIT, SABK, Orion and the like are not compatible with remote controllers. The reason is the completely mechanical design of the gas valve and the lack of electrical circuits, where the relay-breaker can be connected.
An exception is gas heat generators equipped with Kare automation and the latest generation of Italian EuroSIT - 820 NOVA valves. In these blocks, electromagnetic valves and special contacts are provided for connecting external thermostats of two types - mechanical and digital.
Setting procedure
To configure the system and select a comfortable temperature, follow these steps:
- Set the maximum temperature with the remote control.
- Start the boiler and bring it to the optimal operating mode, in which the unit reaches the highest efficiency.
- When comfortable heat is established in all rooms, take an electronic thermometer and measure the temperature near your regulator.
- Select the measured value on the thermostat as the heater cut-off threshold. Put the required settings into the programmer.
Important clarification. The gas boiler operates with maximum efficiency at a temperature of 80/60 ° C (supply / return).
Explain the purpose of these manipulations. Due to different areas and heat losses, the temperature in the rooms can differ by 1-3 degrees, so it is better to focus on the degree of heating of the air around the sensor itself.
If at the point of installation of the controller the temperature is very different from the rest of the rooms, during the adjustment you need to make an adjustment for the value of this difference. In some models, for example, Baxi Magic Plus, a function of such adjustment is provided (called - temperature shift). Then it remains only to enter into the memory of the device the desired value, comprising from 1 to 5 degrees.
When does the thermostat not save gas?
There are quite a few reviews of this kind on the Internet: “I was reassured by sellers' assurances of 30% savings, I bought and installed a temperature controller, now the boiler consumes more gas. Why is he needed at all? ” Let's see how this device saves energy (not only gas, but also solid fuel, diesel fuel and electricity):
- The interval between starts of the heat generator is increasing. The reason is that air cooling and heating is slower than water in batteries.
- Together with the burner, the circulation pump is switched off, consuming up to 100 watts of electricity. In TT boilers, the fan stops (turbocharger or smoke exhaust).
- The premises are fully heated at the right time, when residents are at home. During the remaining hours, a reasonable temperature is maintained. It is recommended to reduce the heating even at night - for a comfortable sleep, it is enough to heat the rooms at the level of 18-19 ° С.
Explanation. Reasonably permissible is the temperature with which the boiler quickly warms up the room to a comfortable level without any special energy costs. It is determined empirically and lies within 15-18 degrees.
Now, consider situations where instead of saving, an increased consumption or heating deterioration is observed:
- The boiler has a minimum coolant temperature (40-45 ° C), because the floor heating circuits are connected directly. The heater works with low efficiency, gas consumption does not decrease.
- When the house is heated exclusively by underfloor heating, and the thermostat does not measure in the lower zone of the room. The screed and the air warms up slowly, when the sensor is triggered, the floors become too hot. When cooling, the opposite picture is observed.
- The heat loss of the building is too great. No thermostats will help here, insulation is required.
- A bunch of temperature sensors - the boiler is incorrectly configured, hysteresis is incorrectly selected (temperature difference between starting and stopping the heat generator).
Each temperature regulator provides a temperature difference between turning the boiler off and on. The value can be changed within 0.5–2 degrees. If the maximum hysteresis is selected, and the house is heated by underfloor heating, the temperature difference will increase significantly, the stay in the room will become uncomfortable, and the heat generator will use up more fuel for heating.
Conclusion
According to sellers, thermostats for gas boilers reduce the consumption of blue fuel by 25-50%. The figures are slightly overestimated in order to sell heating equipment to the user. In practice, the amount of savings falls within the range of 10-25%, depending on many conditions. But at current tariffs and energy prices, 10 percent will have a tangible effect, so thermostats are definitely recommended for use.