How to control a radiator

Written by cameron easey
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You can control radiators used with you home heating system by balancing each of the radiators. Balancing will adjust the radiators so they all receive the same amount of water. Normally, radiators that are closest to the boiler will be hotter than radiators that are farther away. By balancing the system, you can control the amount of water being used by each radiator.

Skill level:

Things you need

  • Adjustable spanner
  • Radiator thermometer

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  1. 1

    Turn off the boiler so the heating system can cool down. Wait at least two hours for the water in the heating system to cool.

  2. 2

    Open the lockshield valve positioned on one side of the radiator. The valve may be hidden under a cover that you will need to remove. Place the adjustable spanner on the valve and turn it clockwise to open the valve.

  3. 3

    Place the adjustable spanner on the control valve that is positioned on the opposite side of the lockshield valve. Turn the adjustable spanner clockwise to open the valve.

  4. 4

    Repeat Steps 2 and 3 for all the radiators in your heating system.

  5. 5

    Place a radiator thermometer on the water inlet and outlet pipes on the radiator closest to the boiler.

  6. 6

    Turn on the boiler and let the water heat.

  7. 7

    Close the lockshield valve on the radiator that has the thermometers attached, then wait for the boiler to heat the water.

  8. 8

    Slowly open the valve until the temperature difference between the two thermometers is within -6.67 degrees C.

  9. 9

    Take the thermometers off the radiator and repeat Steps 5, 7, and 8 on the rest of the radiators until they all have been balanced.

Tips and warnings

  • You can use an adjustable wrench to open and close the valves if you do not have a spanner.
  • If you fit the radiator thermometer to the main flow and return pipes, you will get an incorrect reading for the water temperature.

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