How to connect a thermostat to a gas boiler

Thermostat – a special device that automatically regulates the operation of a gas boiler. This is achieved by constantly monitoring the air temperature in the room, adjusting the heating intensity accordingly.

How to connect a thermostat to a gas boiler

Methods of boiler operation control

All control options are divided into manual and automatic. The former involve directly adjusting the boiler’s operation intensity by changing the gas supply volume, which is inconvenient. The latter adjust all this through remote controls and special thermostats.

Principle of thermostat operation

The thermostat with a gas boiler operates in a fully automatic mode, with human intervention only occurring at the stage of setting the target temperature. If a deviation is detected, the corresponding command is sent to the boiler. If the daily or weekly room temperature reaches the upper set parameter, the boiler shuts off, and if it drops to the lower limit, the equipment switches on. At the same time, the circulation pump is also controlled. This reduces heating costs by up to 35% by reducing natural gas and electricity consumption. Approaching the threshold value can occur in the following cases:

  • during a thaw outside, when the temperature difference between indoor and outdoor decreases, reducing heat loss;
  • heating of the room by sunlight through windows;
  • an increase in the number of people, where temperature adjustment is done manually or automatically;
  • heat entering through enclosing structures;
  • high energy efficiency of the house.

The feature of the thermostat’s principle of operation and manual adjustment is in its use of room air temperature, not the heat carrier. As a result, there may be a situation where the radiators are cold, but the room temperature is sufficient to keep the gas boiler off.

How to connect a thermostat to a gas boiler

What a gas boiler thermostat looks like

The energy source for the gas boiler thermostat is usually several batteries, making it versatile and allowing it to operate independently of the mains. This minimizes installation work, eliminating the need for wall chiseling and external wire routing.

How to install and connect a thermostat to a gas boiler

The first step is to determine the location for installing the gas boiler thermostat. It should be a typical residential room, not the kitchen, boiler room, or large hallway. In the latter, the automatic room temperature mode will be disrupted, leading to instability in the operation of the entire home heating system. The optimal option would be a room where people frequently gather or the coldest (usually a corner) room. When determining the specific installation location, adhere to the following rules:

  • the device and automatic sensor should not be exposed to direct sunlight;
  • the thermostat should not be placed where drafts are regularly detected;
  • there should be no electrical appliances, heating radiators, or other heat sources nearby;
  • the thermostat’s mounting height should not exceed one and a half meters above the floor (otherwise, there will be distortion in room temperature due to the rise of heated air);
  • the gas boiler thermostat should not be installed on a cold external wall of the building, where the temperature will be lower;
  • the device should have free access and full air circulation, meaning the thermostat should not be obstructed by furniture.

Adhering to these recommendations will prevent temperature distortions on the device sensor and contribute to maintaining a comfortable room temperature, reducing heating costs through the device by reducing the volume of generated heat.

How to connect a thermostat to a gas boiler

Thermostat installation process

Most modern gas boilers already allow for the connection of an external thermostat. They have special elements to which cables or terminals supplied with the automatic regulator are attached. The choice of a specific connection depends on the boiler and thermostat models, taking into account the specifics of the heating equipment. The thermostat is directly connected using wires and wireless connection. The latter option is convenient when the house’s area is large, and the distance between the boiler room with the gas boiler and the thermostat’s installation location is considerable. The thermostat consists of two principal blocks, where one is installed in the control room, and the other is placed next to the boiler. The specific installation process is detailed in the technical documentation for the equipment.

In general, the sensor is connected to two contacts. In the standard state, they are connected by a jumper on the boiler, ensuring circuit closure. In modern models of heating boilers, it is often brought out to a separate terminal block, where the thermostat is simply connected. With the correct installation, the latter either allows or does not allow current to pass through itself, automatically turning the heating boiler on or off. Installation itself does not require special tools, and a multimeter for voltage testing, a regular screwdriver, and tools for attaching individual devices to the wall in the room will suffice.

The installation of the room thermostat sensor involves attaching the wire ends to the boiler terminal and then testing the operation. The latter involves observing the boiler’s operation when changing settings on the thermostat.

How to adjust the boiler thermostat

After connecting the thermostat sensor, it needs to be adjusted. First, study the device documentation because the specifications can vary significantly depending on the model. Usually, on the front surface of the room programmer, there are several switches or keys for making adjustments to the settings. In different models, you can find options for adjusting the following parameters:

  • Threshold values of daily and weekly room temperatures in the target room, reaching which should turn the boiler on or off;
  • setting heating or air conditioning depending on the type of gas equipment to which the programmer with settings for weekly or daily room temperature is connected;
  • adjusting the delay in the programmer’s operation (relevant during ventilation, when the room air temperature temporarily drops sharply, and in some cases, falls below the boiler activation level considering the established minimum daily and weekly limits).

Depending on the model, the thermostat (programmer) may allow setting several temperature operating modes of the gas boiler in a weekly or daily schedule. We are talking about daytime and nighttime operating modes, where the room temperature decreases during the dark hours and gradually increases with the help of the programmer by morning. This approach simultaneously reduces heating costs, creates comfortable sleeping conditions, and makes it easy to wake up in the morning. Additionally, thermostats often have several built-in operating programs available for quick activation. This is relevant for long absences of homeowners when the system can be switched to heating mode with one button press (here you can set a weekly schedule for adjusting room temperature).

How to connect a thermostat to a gas boiler

Which thermostats are better to choose for gas boilers

There are mechanical and electronic thermostats for gas boilers. In our opinion, the latter are more convenient. Devices from well-known brands like Baxi, Bosch, Protherm, and others provide more accurate adjustment of daily room temperature, have extended functionality with not much difference in price, which will be returned by heat savings.

Advantages of thermostats (programmers) for gas boilers

The main advantage provided by installing a thermostat ACV on a gas boiler remains a reduction in heating costs by reducing gas consumption while maintaining a comfortable daily room temperature. Expensive thermostat models significantly increase savings, amounting to a minimum of 10-15%. In addition to increasing overall energy efficiency, such weekly and daily room temperature programmers in an apartment or house provide several advantages:

  • Increased stability of gas heating equipment operation after installing the thermostat (programmer) due to reducing the number of cycles of turning on and off, which positively affects durability and operational time before failure;
  • the possibility of precise manual adjustment of the daily or weekly room temperature mode on the gas boiler programmer considering personal preferences, making staying at home more comfortable;
  • simplicity of connecting the programmer to the gas boiler, which can be done independently with minimal skills after studying the connection instructions;
  • overall simplification of operation and adjustment of the gas heating system in the house, apartment, by abandoning the manual inconvenient method.

In the end, the initial expenses for installing a thermostat (programmer) from Baxi, Protherm, Bosch, Ariston will ensure comfortable daily and weekly room temperatures, real savings that will pay off the costs within one or two heating seasons.