One Radiator Not Working in One Room: Common Causes & Fixes

A malfunctioning radiator in one room is a common but frustrating issue many homeowners face. Whether the radiator is not heating up at all or only warming partially, it could leave one room uncomfortable while the rest of your home remains cozy. In this guide, we’ll dive deep into why this happens and how to fix it. We’ll also explore preventive measures, common mistakes, and when to call a professional.

Key Points Covered:

1. Common causes of a single radiator not working.
2. DIY fixes for the most frequent issues.
3. The cost of professional repairs.
4. Long-term radiator maintenance tips.
5. When to hire an expert to handle radiator issues.

Why Would a Single Radiator Stop Working?

When only one radiator is not working while others in the house are operating normally, it’s essential to troubleshoot the issue methodically. The most likely causes of a radiator malfunction in one room include:

• A stuck thermostatic radiator valve (TRV).
• Trapped air inside the radiator.
• Imbalance in the system causing uneven heat distribution.
• A faulty lockshield valve restricting water flow.
• Potential blockages in the radiator pipes.

Let’s examine each of these in more detail.

Read about: Best Thermostatic Radiator Valves UK

1. Thermostatic Radiator Valve (TRV) Stuck

A thermostatic radiator valve (TRV) regulates the flow of hot water into a radiator. These valves often get stuck, especially in older systems or if they haven’t been used for a while. When the TRV becomes stuck in the closed position, no hot water can enter the radiator, leaving it cold even when the heating is on.

Signs of a Stuck TRV:

• The radiator remains cold, even when the heating is turned on.
• The rest of the radiators in the house are working fine.

Fixing a Stuck TRV:

Here are the steps to check and fix a stuck TRV:

1. Turn Off the Heating: Before attempting to fix the TRV, ensure that your heating system is turned off. Let the radiator cool down entirely before you start working on it.
2. Inspect the TRV: Remove the TRV’s head by unscrewing it. You will see a small pin underneath. Press the pin gently with your finger.

• If the pin moves freely and pops back up, the TRV is likely functioning correctly, and you should look for other issues like trapped air.
• If the pin is stuck in place, it means the TRV is indeed the problem.

1. Use Grease or WD-40: Apply a small amount of lubricant to the pin, such as WD-40 or a similar product. Use a pair of pliers to gently work the pin up and down until it moves smoothly.

• Warning: Be cautious not to force the pin too hard, as this could cause permanent damage to the TRV.

1. Test the Heating: Once the pin is moving freely, reattach the TRV head and turn the heating system back on. Check to see if the radiator is heating up properly.

If the pin won’t budge or you’re uncomfortable handling this fix, call a heating engineer to replace the valve or fix the issue.

Read more: How to Bleed a Radiator

2. Air Trapped in the Radiator

Another common reason for a radiator not working is trapped air. When air gets into the radiator, it rises to the top, preventing hot water from circulating. This results in a radiator that is warm at the bottom but cold at the top.

Symptoms of Trapped Air:

• The top of the radiator is cold while the bottom is warm.
• There may be gurgling sounds coming from the radiator.

How to Bleed a Radiator:

Bleeding a radiator is a simple DIY process to release the trapped air. Follow these steps:

1. Turn Off the Heating: Let the radiator cool down entirely to prevent hot water from spilling out.
2. Prepare for Spills: Place old towels or rags around the radiator and have a bucket handy to catch any water that escapes during the process.
3. Locate the Bleed Valve: The bleed valve is usually located at the top of the radiator. It can be opened with a radiator key or, in some models, a flathead screwdriver.
4. Open the Bleed Valve: Slowly turn the valve counterclockwise until you hear a hissing sound. This is the trapped air escaping. Once water starts to dribble out, close the valve by turning it clockwise.
5. Check Boiler Pressure: Bleeding a radiator can sometimes lower the pressure in your boiler. Check the pressure gauge, and if it has dropped below 1 bar, you may need to repressurize the system. Follow the manufacturer’s instructions to do this safely.

Once the air is released, turn the heating system back on and check whether the radiator is heating up properly. If the problem persists, it might indicate another issue, such as an imbalance in the system.

Read about: Radiator Cold at the Bottom

3. Imbalance in the Radiator System

If you have multiple radiators, some may heat up faster than others, or the radiator furthest from the boiler may struggle to heat up. This imbalance happens because the hot water is not distributed evenly throughout the system. The lock shield valve, typically located on the opposite side of the TRV, controls the flow of hot water to each radiator and might need adjusting.

Symptoms of Imbalance:

• Some radiators heat up faster than others.
• The radiator furthest from the boiler stays cooler.

How to Balance Your Radiators:

To balance the radiators in your home:

1. Turn Off the Heating: Let the system cool down completely before starting.
2. Open the Valves: Fully open all the TRVs and lockshield valves in your home.
3. Adjust the Lockshield Valves: Starting with the radiator closest to the boiler, use a spanner to partially close the lockshield valve. Move to the next radiator and adjust its lockshield valve slightly less than the previous one. Repeat this process for all radiators in the system.
4. Test the System: Turn the heating back on and monitor the radiators. Each should heat up at a similar pace. If one is still slower to warm, fine-tune the lockshield valve on that radiator until the system is balanced.

Balancing radiators can be tricky, so don’t hesitate to call in a professional if needed.

4. Faulty Lockshield Valve

If bleeding the radiator and balancing the system don’t solve the issue, the lockshield valve itself might be faulty. A lockshield valve controls how much hot water enters the radiator. When it malfunctions, it can block water flow, leaving the radiator cold or partially heated.

Fixing a Faulty Lockshield Valve:

1. Turn Off the Heating: Let the system cool down before handling the lockshield valve.
2. Check the Valve: Use a spanner to gently open and close the valve. If the valve is stiff or won’t turn, it may need to be replaced.
3. Replace the Valve: If the valve is beyond repair, you’ll need to replace it. This job is best handled by a professional, as it involves draining the system and installing a new valve.

5. Blockages in the Radiator Pipes

In some cases, the problem may be due to a blockage in the radiator pipes. This can happen over time, especially in older systems, as sludge builds up inside the pipes and restricts water flow.

Symptoms of a Blocked Radiator:

• The radiator remains cold despite all other solutions.
• The radiator makes strange noises, such as banging or gurgling.
• The radiator is cold throughout, not just in specific areas.

How to Fix a Blocked Radiator:

Fixing a blockage usually requires a professional power flush, which involves forcing water through the pipes at high pressure to remove any buildup. This is not typically a DIY job, so contact a heating engineer if you suspect a blockage.

Cost of Hiring a Professional for Radiator Repairs

While many radiator issues can be fixed with simple DIY methods, there are times when hiring a professional is necessary. Below are the average costs for common radiator repairs:

• Fixing a stuck TRV: £30 – £60
• Replacing a TRV: £40 – £120
• Bleeding one radiator: £30 – £60
• Bleeding all radiators in your home: £60 – £180
• Power flushing the system: £300 – £700 (depending on the size of your home)

Keep in mind that prices can vary based on your location. For example, heating engineers in the southeast of England may charge more than those in the north of England or Scotland.

Preventive Maintenance Tips for Radiators

To avoid radiator problems in the future, regular maintenance is essential. Here are some preventative tips:

1. Bleed Radiators Annually: Even if your system is working fine, air can accumulate over time, so bleeding your radiators yearly can help keep the system running efficiently.
2. Inspect TRVs and Lockshield Valves: Check the functionality of your valves regularly. If you notice stiffness or difficulty adjusting them, address the issue early to avoid future malfunctions.
3. Regular System Flushing: Every few years, consider having your system flushed by a professional to remove sludge and debris that can cause blockages.
4. Annual Boiler Servicing: Keep your boiler in top condition with an annual service. This helps prevent low boiler pressure, uneven heating, and other system-wide issues.

Read more about:

best boilers in uk

FAQs