How to Balance a Radiator

You may be wondering how to balance a radiator if you find that there are noticeably cold or hot spots on your radiators. Typically you’ll find that over a period of time your radiators may not be providing you with the necessary warmth needed. In order to correct this, we recommend regular radiator balancing.

Don’t panic, this isn’t the end of the road for your heating system, just some necessary maintenance. There are several quick and easy ways to fix this problem through some simple DIY tricks. By following our simple step-by-step walkthrough, you’ll be armed with all the tools needed to balance your radiator yourself.

Firstly, before starting, make sure you have the following tools with you before you begin:

  • Screwdriver
  • Radiator Bleeding Key
  • Adjustable Spanner or Lockshield Valve Adjuster
  • Digital Thermometer

Step 1: Switch Off the Heat

The most important thing to do before starting is switching off the heat. You need to wait until the entire central heating system has cooled before beginning and ensure that your radiators have been bled. If you don't know how to bleed, take a look at our guide on how to bleed a radiator at home.

We’d recommend switching off the system the night before in order to give it the whole evening to cool.

Step 2: Know Your Valves

Every nut and valve is slightly different from each other, particularly varying between different radiators. Therefore, before you begin the procedure, know the different valves that are used on your radiator.

Each valve is used for a specific purpose and thus, we’d recommend carrying out some research about valves before applying a particular technique. For example, a lockshield valve normally has push-on cap which is secured with a screw on top of it. If you have this valve, make sure to remove it completely.

Step 3: Release the Valves

Open all the valves attached to the radiator and release them by moving them anti-clockwise. You’ll probably need a spanner or adjuster in order to open the lockshield. Alternatively, you can quickly open the thermostatic valves or wheel head valves which were used earlier with a twist from your hand.

Step 4: Turn On the Central Heating System

Once you’re done opening all the valves, you can turn on the central heating system and note down the heating order of the radiator. A common thing you might notice is that the radiator closest to the boiler is likely to heat up the first, for obvious reasons. If you’re testing a number of rooms make a point to enlist some help so that you can accurately test the heating order. We’re confident your friends will be queuing up to help you test your radiators!

Step 5: Turn Off the Central Heating System Again

Again, turn off the heating and give your radiators time to cool down. Whilst you’re waiting, we’d recommend taking a look at the Great Rads selection of designer radiators, to help the time fly past faster.

Step 6: Turn Heating Back On & Locate the First Heated Radiator

Once all your radiators have cooled, turn on the heating again and go back to the radiator that heated first during your tests. Close the lockshield valve completely on the radiator by turning it clockwise, before opening it just a quarter of a turn.

Step 7: Note Down the Temperature

Once the radiator has been reheated, take a note of the temperature reading for the pipe leading to the radiator.

Step 8: Note Down the Temperature On the Opposite Side

The next step is to note temperature of the valve on the other side of the radiator to the one you’ve just measured. You should next begin opening the lockshield valve until there’s a 12°C difference between the 2 valves.

Ensure that you leave a few minutes between changes to the valves so that you acquire an accurate reading for any change in temperatures.

Step 9: Repeat Steps 1 - 8 for Each Radiator

Make a point of repeating the above steps for each radiator, in order of how they heat. Typically, you’ll find that the farthest radiator from the boiler will have the greatest valve opening. It’s possible that in order to balance your radiators the lockshield valve of the farthest radiator will end up being completely open, but this isn’t always the case.


You’ve now managed to balance all your radiators. After a productive weekend well spend, it’s your time to relax and enjoy the soothing warmth.


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