What You Must Do If One Radiator Is Not Working

Winter is the coldest time of the year and your house is the safest place to hide from the harsh weather. The radiators in the house make it more comfortable by heating the rooms. A radiator can work flawlessly for years without any significant issues.

In some unfortunate circumstances, the room can be cold but the radiator won’t simply turn on. In such events, don’t panic. Most of the problems are minor that you can handle from home. So chill out if your radiator is not working and learn an easy solution.

But first things first, right?

Why Is Only One Radiator Not Heating Up;

Before we try to give solutions to the heating problem, we will look at the malfunction’s potential cause. As with other technologies, any point of failure can cause the entire system to collapse.

  • Boiler Issues

If you are getting into the winter, often the boiler setting is not adjusted to the season. Confirm the boiler settings to be on the safe. Always ensure that the combi- boiler is set for both hot water and heating.

The summer setting can also cause a problem. The worst fault that could plague the heater is having a fault code displayed. Viessmann Boilers have a fault code page that aids you in sorting the issues.

Any of these issues with the boiler will affect the heating up of the radiator.

  • Faulty Heat Pump

S heating systems have a heat pump. When heat pumps stop working, they stop heating the water needed to keep the radiator warm. You can confirm that the heat pump is running if it is making some noise or vibrating.

  • The air in The Radiator

Air can leak into the radiator and cause uneven heating. The air in the system gathers at high points of the radiator to stop the correct heating water distribution. You will notice this issue if the radiator is warmer on the lower side but cold at the top.

  • A Stuck Thermostatic Valve

A cold radiator may not be due to any large systemic issues. A single thermostatic valve can bring a whole radiator to a halt. The thermostatic valve is a white control at the bottom of the radiator.

The valve regulates the amount of hot water entering the radiator. But once in a while, the valve gets overwhelmed due to ageing in most cases. When the valve stops, hot water cannot enter the radiator hence a cold radiator.

To confirm that the problem is with the valve, remove the rotatable head to reveal the raised in under it. Depress the pin with a finger and observe. If the pin rises with the pressure, it is appropriately functioning.

If you get the pin already depressed or it fails to raise with the pressure, you have found the radiator’s main culprit of malfunction.

  • Low Water Pressure

Once you confirm that either the boiler or water pump is in good working condition, you have to confirm the water pressure. The water pressure is read on the manometer. The ideal pressure to run the radiator is 1.0 bar.

  • System Imbalance

If you notice that a radiator upstairs is working correctly and one downstairs is cold, it may be due to system imbalance. Hot water tends to rise upward whilst cold water goes downwards.

If you get this clue no need to go to check all other issues; start repairs.

One Radiator Not Working? Here Is What You Must Do

Now that we can all diagnose problems facing the radiators, it’s time to get the possible remedies and get your house warm again.

  • Confirm If All the Other Radiators Are Working

Before you open your radiator to start any repairs, confirm that all the other radiators are working. You may be facing a system-wide problem, yet you are fixing a local issue. In case all other radiators are working, confirm if the radiator is switched on.

If you have a problem with the boiler not heating all the radiators, we can concentrate on the boiler. Confirm if there is hot water coming out of the pipes. Confirm that the boiler is not in a summer setting and adjust. For combi-boilers set on both hot water and heating.

For boiler errors, always go through the boiler manual to get to see the solution. However, when things seem too technical, don’t be afraid to call a technician.

Suppose the pressure has run out it because you are using a central high-pressure system. Adjust the pressure dial to the manual’s recommended pressure and add some water to the system if necessary.

  • Bleed the radiator

What is bleeding the radiator? Is it live! Don’t worry, bleeding the radiator has nothing to do with blood. You bleed the radiator if you believe there has been some air leakage in the radiator. Bleeding is simple, and you should be able to handle it on your own.

Using the radiator key, unscrew the bleed screw till you hear a hissing sound. That is due to the radiator letting out air; when it is done, it will start letting out water. At this point, close the bleed screw.

  • Clean or Power flush the radiator.

Sometimes bleeding the radiator is not enough. In this case, cleaning the radiator is the most viable solution. The bleeding failed to work due to the accumulation of dirt, grime, and rust at the radiator’s bottom.

Turn off your heating system and all radiator valves till the entire system cools off. Take out the radiator from the wall. Bleed it and take it out and run water through the unit by attaching a hose to the valve outlets. The process is often called power flushing.

After flushing with clean water, reconnect to its pipes and reattach to the wall. Configure it to its original state.

  • Tap the Stuck Valve

When you establish that the valve is out of place, tap the stuck pin to free it. However, be careful because extra force can damage the valve.


Now you know what to do when you have a radiator not getting hot; you can restore your house’s warmth in case of mishaps with the radiator. Follow the instruction carefully for the best results. Consult a professional for places you don’t understand.