Common Radiator Issues and How to Fix Them

Almost every UK home has a central heating system with radiators to keep them warm and comfortable throughout the cold season. After not being used for a long time, these radiators are likely to develop some issues. But don't worry, you can sort most of them with some DIY fixes over a weekend.  

In this guide, we'll explain common radiator issues and how to fix them. Keep reading to know what to do if you can’t fix your radiator right away. 

Radiators and How They Work 

Radiators are part of the central heating system inside your home. Usually, they’re in each room to transfer heat from hot water into the air and warm up the space. A central heating system might include: 

• A boiler to heat water 
• Pipework to carry hot water throughout the house 
• Radiators in each room to release heat from the hot water 
• Thermostatic radiator valves or a central thermostat to control the temperature 

The way it works is simple. Hot water flows from the boiler through the radiators, releasing heat into the room before returning to the boiler.  

Common Issues That Prevent Radiators from Heating Properly

If your radiator is not working or heating up properly, something may be blocked in the system. To identify the root cause, check each component of the heating system. Here are the most common problems you may encounter. 

Cold Spots on Radiators 

Sometimes, you might find parts of the radiator, often the top and middle, aren't heating up properly. This usually means hot water isn't being evenly distributed throughout the unit. The cause may be trapped air or rust buildup inside the radiator.  

Fix: 

• Bleed your radiator to release the trapped air at the top of the radiator. 
• Power flush the radiator to remove sludge build-up if the cold spots are in the middle or bottom. To prevent future issues, install a magnetic filter to stop sludge accumulation. 

While you're fixing the issue or waiting for an engineer, portable heaters can be a quick, reliable way to stay warm without spending a fortune.

Leaking Radiators 

Radiator leaks are easy to spot. Just look for small puddles or damp patches around the pipe joints. These can be caused by loose connections, worn seals, or corrosion inside the radiator over time. 

Fix: 

• Turn the radiator off 
• Tighten the valve or nut slightly 
• Replace the seal if it's worn with suitable DIY tools.
• If the corrosion is severe or the leak continues after tightening, call a heating engineer. In some cases, the radiator may need to be replaced entirely.

Incorrect Use of Thermostatic Radiator Valves (TRVs)

Every radiator comes with a Thermostatic Radiator Valve (TRV), which controls the water flow and room temperature. Incorrect use of the radiator valve might make the room too hot or too cold.  

Fix: 

• Inspect and make sure that the TRV on your radiator is working properly 
• Avoid covering it with clothes or curtains to ensure accurate temperature readings 
• Set the TRV according to the desired temperature (level 3 - 20°C is recommended for a comfortable temperature)
• If the TRV feels stuck or is completely broken, you may need to buy a new one and replace it. Contact a professional if you're unsure of how to do this yourself.

Noisy Radiators 

If you can hear banging, gurgling, or knocking noises from your radiators or pipes, there could be several causes: 

• Air trapped in the system 
• Water pressure is too high 
• Loose water pipes 

Fix:  

• Bleed the radiator to release excess air 
• Check your boiler pressure gauge and reduce it if it’s too high 
• Inspect the pipework and secure any loose connections 

This issue might take time to assess and fix. In the meantime, consider alternatives like radiant heaters to warm your house up quickly and safely.

Uneven Heat Across the Rooms 

If you're finding that radiators in some rooms are heating up more than others, it might be that your system is unbalanced. This means hot water flows more easily to some radiators than others.

Fix:

• Balance the heating system by adjusting the lock shield valves on each radiator 

What to Do If You Can't Fix Your Radiators 

Quick fixes can solve many common issues, but some problems may require professional help. 

Call a Professional

If your radiator doesn't heat after bleeding and adjusting valves, a qualified heating engineer. They can help you power flush the system, repair faulty valves or diagnose tricky issues with the boiler and pipework. 

Using Portable Heaters as an Alternative 

While waiting for an engineer, don’t stay cold—hire a portable heater instead. They're a quick and cost-effective alternative to central heating.  

• Focus heat in a specific area or room 
• Portable and easy to move around the house 
• Available in fuel-powered and electric models 

Hiring portable heaters while getting your radiators fixed is much more affordable and reliable to keep your home warm and comfortable.  

Speedy offers all kinds of portable heaters, such as oil-filled heaters, fan heaters to infrared units. Read our heating hire guide for more information and choose what's best for you!

Check out all Portable Heaters at Speedy

Our portable heaters are well-maintained, energy-efficient, and ready to use, giving you instant warmth when your central heating fails. They’re quick to set up, safe for home or workplace use, and available in a range of sizes to suit any room. Get them delivered in just 4 hours or collect from over 200 depots around the UK!