Part of the house is cold

If there is warm heating water but not every radiator or underfloor heating loop gets warm, your heating system is out of balance. To keep the text concise, we will use the term radiator, but the steps also apply to an underfloor heating loop.

Air in the radiator

Air in a radiator or underfloor heating loop does not heat up, so the radiator or loop remains cold. This is often accompanied by rushing noises.

• Bleed the radiator or underfloor heating loop and check whether it reaches the correct temperature again.

If there was no air in the radiator, continue with the following steps.

Check the water flow

The heating water is warmest when it has just left the heat pump or central heating boiler and cools down as it flows through the house. By making it more difficult for the heating water to flow through the first radiators and easier to flow through the radiators further along the system, you can help ensure that every radiator in the system gets warm.

If one or more radiators remain cold, the flow rates have not been adjusted correctly. Adjusting these flow rates is also known as hydronic balancing.

Follow the steps below to improve the balance of the system:

• Check the flow rate of your heating water in the App.
  • Is the flow rate more than 20 liters per minute? Partially close the thermostatic radiator valves on the radiators that do get warm.
  • Is the flow rate less than 20 liters per minute? Open the lockshield valve on the cold radiator further.
    • With an underfloor heating manifold, the flow rate can often also be adjusted for each individual loop.
• Check whether the radiator now gets warm. If not, repeat the steps above.

For a more detailed description on hydronic balancing, see this page: Hydronic balancing of your system

Faulty thermostatic radiator valve

The thermostatic radiator valve may be faulty or stuck. You can check this by removing the thermostatic head and gently pressing the pin protruding from the valve body.

Is the pin difficult to press, or does it remain fully pressed in? If so, the valve is no longer working properly. Try to free the pin or replace the thermostatic radiator valve.

Underfloor heating does not get warm

Do you have a mixed heat distribution system with both radiators and underfloor heating, but the underfloor heating does not get warm? Check the points above for the underfloor heating as well.

In addition, check the underfloor heating manifold:

• What temperature is the underfloor heating manifold set to?
• Is the mixing pump on the underfloor heating manifold working?

Have you checked all the points above, but part of your home still remains cold? Contact Support and describe which steps you have already taken or where you are experiencing difficulties.