Thermostats mounted to boiler

To boiler/heater

— devices built directly into the heating device. This installation method is popular primarily among thermostats used in solid fuel boilers — the design features of such devices are such that it is easiest to make them built-in. In this case, part of the body is located directly in the boiler furnace, and control is carried out through a chain that controls the damper.

There are other types of thermostats installed in the boiler/heater, but much less frequently. Speaking of such devices, it is worth noting that, on the one hand, they do not have a division into an external and internal unit, which simplifies installation and reduces cost; on the other hand, placement directly on the heater is not always the most convenient option.