how to balance radiators

How to Balance Radiators

Knowing how to balance radiators can save you money, but cost you time. Balancing radiators can take a long time, but it can be very rewarding. Getting all of your radiators to the same temperature is the goal.

I have been replacing radiators and balancing central heating systems for over ten years, and balancing radiators is not one of my favourite jobs to do, but it has to be done. Most central heating systems do not need balancing, but sometimes they do.

All you need is an adjustable spanner or some plumbers grips, and a laser thermometer (my preference) but you can use any type of thermometer you can hold on the radiator. I used just my hands for the first few years, but it’s probably not the best idea.

Balancing Radiators

For balancing radiators, all you need is an adjustable spanner. Make sure you have bled all radiators in your house and opened all radiator valves to make sure your central heating system needs to be balanced.

There is no point trying to balance the central heating system until you have tried to bleed each radiator first. Bleeding the radiators should be the first thing to try when you have radiators that are not getting hot. This is the simplest solution to try first.

If you are still having problems with some radiators not getting hot or as hot to touch as others, then balancing your radiators is the next step to heating your home properly.

How to Turn Off Radiator Valve

To turn off a radiator valve for balancing radiators, you need to close a lockshield valve. If you have thermostatic radiator valves (TRVs) on any of your radiators, these need to be fully open for balancing the central heating system.

If you do not turn off the thermostatic valves, the radiators will turn off when balancing the system when they have reached the temperature set on the TRV and mess things up.

To turn off a lockshield radiator valve, you have to turn the top of the valve clockwise as far as it will turn. If it has a handle, you can use your hand. If not, then you will have to use an adjustable spanner or some plumbers grips.

How to Balance a Central Heating System

To balance a central heating system, you have to spread the heated water evenly around your radiators. You do this by restricting the water from going to the hotter radiators and forcing it to go to the colder radiators.

My step-by-step process for how to balance a central heating system –

  • Leave thermostatic radiator valves fully open on maximum setting at all times!
  • Close one lockshield valve on all the radiators that get really hot.
  • Do not touch the cold radiators that you are having problems with, and turn the heating on.
  • The cold radiators should now get hot, and the normally hot radiators shouldn’t have any heat at all.
  • If the problematic radiators are still not hot, then balancing your radiators is probably not the solution to your problem.
  • Open all the closed lockshields a quarter turn with an adjustable spanner or another tool.
  • Leave it for half an hour or so to let the system heat up.
  • Go around with your thermometer and check the temperature of all the radiators and make notes of what they are.
  • Then go around tweaking each radiator via the lockshield. If a radiator is not as hot as the others, then open the lockshield a little more. If any of them get hotter than the radiators that are fully open, then close them a little.

Some lockshield valves are very sensitive to the smallest of turns, so you might go back and forth a few times from too hot to too cold with certain radiators before you get it right. It can be very time-consuming and frustrating.

When you tweak a radiator you need to leave it a while to reach the new temperature, so just keep going around all the radiators checking and tweaking. They don’t have to be the exact same temperatures, but you want them as close as possible.

When you have got them as close to the same temperatures as possible, turn the heating off and let it cool down fully and then turn the heating back on and check temperatures again, then get tweaking again if needed.

How to Balance Radiators Without Thermometer

To balance radiators without a thermometer, you can use your hands to feel the temperature of the radiators. This isn’t very accurate, but I did this for a few years when I started out, before buying a laser thermometer for around £20.

If your radiators need balanced, then there should be big differences in the radiator temperatures between the radiators that are not hot enough and the ones that are. So balancing the radiators without a thermometer is still going to work.

Just follow the step-by-step process above and use your hands to feel the radiator temperatures instead of a thermometer. They should all be too hot to keep your hand on for too long, ideally, or close to.

Unbalanced Radiators Symptoms

Unbalanced radiators symptoms are cold radiators or radiators that are not hot enough to heat the room properly. Which means cold rooms. Most central heating systems I work on have all unbalanced radiators.

If you have cold radiators, this does not mean they are cold because they are unbalanced, it could mean you need to bleed your radiators or clean the central heating system.

Balancing Radiators FAQs (Frequently Asked Questions)


When Would You Balance a Central Heating System?

You would balance a central heating system when you are having problems with certain radiators not getting hot.

What Side of the Radiator is the Lockshield Valve?

The lockshield valve is not fitted to any particular side of the radiator. The thermostatic radiator valve is fitted to whatever side is most appropriate for the room that the radiator is in, and the lockshield valve is fitted on the other side.

Sometimes times there is a lockshield valve on both sides of the radiator.

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