The air-to-water heating system is regulated in two steps. The circulation of water in the network of radiators has been balanced by means of presetting both the lines and the individual radiators. The temperature of the water circulating in the radiators is controlled by outdoor air temperature. The setting is complemented by the thermostatic regulators, resulting in an even temperature of 20–22 degrees centigrade in all rooms. With the thermostatic regulator, the room temperature can only be turned down, not up. The thermostat closes and opens the water circulation in the radiator so as to keep the room temperature even. When there is enough heat in the room from other sources (such as the heat generated by household appliances and by people), the thermostat reduces the flow of warm water in the radiator. That is why the upper part of the radiator may be warm at times but at other times the whole radiator may be cold. The thermostat must not be covered with curtains or furniture or be left under a worktop, for that will make the room colder. The access of room air round the thermostat must be kept free.

You may adjust the thermostat only to the extent that the adjusting knob moves freely. It will not necessarily turn from one end of the dial to the other. You are not allowed to open the thermostat and interfere with its initial adjustment. The bleeding of the radiators is a maintenance person’s job. It is up to you to take care of the cleaning of the radiators. Dust accumulating between the radiator panels will hinder the air circulation and reduce the output of the radiator.

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