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Hot water heating systems have a two-stage adjustment. The water circulation of the radiator network is balanced with line-specific and radiator pre-adjustments. The temperature of water circulating in radiators is controlled by the outdoor temperature. In addition, thermostatic valves are used to achieve a uniform temperature of approximately 21 degrees in all rooms. The temperature cannot be set higher than this with the thermostat; it is only possible to decrease the temperature.

The thermostat regulates the flow rate of circulating water keeping the room temperature uniform. Because of this, the radiator feels warm during heating and cool when the thermostat has detected an adequate level of room temperature. The thermostat must not be covered with curtains, etc. as this would result in a higher temperature near the thermostat compared to the rest of the room leading to the closing of the thermostat switch and the room becoming cold.

You can adjust the thermostat only within the free movement range of the knob. Opening the thermostat and tampering with the basic adjustments are not permitted. Radiators are deaerated by maintenance persons. Keep the radiators clean. Dust between the radiator panels prevents circulation of air and degrades the radiator’s performance.

What to do if your room feels cool?

  • Turn the radiator thermostats to the maximum setting
    • In this way, you can ensure that the radiator really generates enough heat to achieve the optimum 21 degrees.
  • Gurgling noise coming from the radiator?
    • The radiator has air inside and should probably be deaerated. Report a fault on the Koas website!
  • Is the radiator feeling cold? Check if there are any blocking items
    • Curtains or furniture in front of the radiator prevent the radiator from heating the room.
    • If a curtain, piece of furniture or other item is in front of the thermostat, the thermostat will sense only the temperature of the background of this item and not the actual room temperature. Water circulation in the radiator stops because the thermostat ”misinterprets” the room temperature as high.
  • Do other heat sources disturb the operation of radiators?
    • Do you frequently use the oven for cooking, can hot steam escaping from the bathroom enter the apartment or does your own sauna transfer heat elsewhere in the apartment?
    • Although the heat of the oven feels comfortable for a while, it actually disturbs the heating system!
    • The moment of warmth may backfire: water circulation in the radiator stops as the thermostat detects a high room temperature.
  • Measure the room temperature in a correct way
    • Measure the room temperature in the centre of the room, just over one metre above the floor.
    • A suitable place for this is the intermediate wall between the rooms in the middle of the apartment, however, not the exterior wall, window sill or a draughty place.
    • Monitor the temperature: does it stay at about +21°C?
  • Temperature constantly below +21°C?
    • Oh no, something is wrong. Nothing to worry about, maintenance people can help! Report a fault conveniently at the Koas website!
    • Fill in the fault report carefully indicating, for example, what you have already done so that the maintenance staff can take the measures that are necessary specifically in your house and apartment.

We are all used to different indoor temperatures and it is completely ok! In Finland we are more or less used to the fact the also the indoor temperatures fluctuate when the outdoor weather changes. Also, it is not only a studied health issue but also an environmental issue to maintain the indoor temperature at +21. Thank you for your cooperation in keeping an eye on your room temperature and in case of trouble, fill in the fault report.