Common Radiator Issues and How to Fix Them

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 from the boiler travels through the pipework to reach radiators in each room. Through the racks, they release heat and warm up the air. When water gets cool, it will be transferred back into the boiler for reheating.

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 that 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 build-up inside the radiator. To identify, carefully use your hand to feel the cold spots. If it lies at the top, the cause is likely to be trapped air. If you feel cold in the middle or the bottom, you might have rust build-up in those areas.

Fix: 

If the root cause is trapped air, bleeding your radiator should help resolve it. Read our blog on How to Bleed Your Radiator for experts' advice and instructions. Otherwise, you might need to power flush the radiator to remove all the sludge build-up. To prevent future issues, installing a magnetic filter is a great idea 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: 

When spotting a leak, you need to turn the radiator off and tighten the valve nut slightly. You can further 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: 

Before fixing or replacing TRVs, double-check and inspect to determine if they can work properly. If they are still in great condition, the problem might be wrong temperature estimation from external factors. Check if you usually cover it with clothes or curtains, or any other factors that might prevent accurate temperature readings.

​Our experts recommend setting the TRV at level 3 (20°C), which is recommended for a comfortable temperature. Maintaining a stable temperature setting also promotes the lifespan and efficiency of the TRV. 

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:  

This problem seems more complicated and time-consuming to identify and fix. You should do several tests to see where the noise comes from. Some simple fixes are: bleeding the radiator to release excess air, checking your boiler pressure gauge and reducing it if it’s too high, and inspecting the pipework and securing any loose connections.

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:

You can resolve the problem by balancing the heating system. Do this 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, you should reach out to 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!