March 05, 2023 Heating, Maintenance Guide Why is my radiator cold?

Are you feeling chilly even though your heating is on? Are you cuddled up under a blanket while your radiators refuse to emit any heat? Are you wondering why is my radiator cold? Well, you're not alone. We've all been there at some point in our lives, shivering and frustrated, wondering what on earth is wrong with our radiators.

Maybe your radiator is giving you the silent treatment because you forgot its birthday, or perhaps it's just having a bad hair day. Who knows, but fear not! In this blog article, we'll delve into the world of radiators and explore the possible reasons why is my radiator cold. We'll go through everything from air in the system to rusty pipes and broken pumps. And who knows, maybe we'll even uncover the secret reason why your radiator is giving you the cold shoulder (pun intended).

By the end of this article, you'll have a better understanding of what's causing your radiators to not heat up, and you'll know how to fix the problem or when to seek professional help. So, let's dive in and get your heating system back up and running efficiently!

1. Air in the system

If you notice that your radiators are not heating up as they should, air may have entered your heating system and become trapped, preventing the hot water from circulating. This is actually a really common issue. Fortunately, bleeding your radiators is a really easy solution.

Start by getting a towel, a radiator key and turning off your central heating and allowing the system to cool down. After all, nobody wants hot water spraying in their face. Once the system has cooled, locate the bleed valve at the top of the radiator and use a radiator key or flat-head screwdriver to open it. If it's your first time doing this, don't open it too much. This will help make sure everything happens a bit more slowly.

You should hear air escape from the valve. Then eventually you'll hear a bubbling noise as the water from inside the radiator tries to escape after all the air has gone. Once this happens, tighten the valve and turn on the heating system again.

Bleeding your radiators like this regularly can help prevent you from wondering why is my radiator cold in the future, and it will also help to ensure that your heating system runs smoothly throughout the year.

2. Blocked radiator

Another reason for your radiator not working could be that there may be a blockage in the system. This can be caused by dirt, rust, or other debris that has naturally accumulated in the system from corrosion.

There are two solutions to this; proactive and reactive. Proactively, you should be dosing your system with chemical inhibitor at least once a year. Preferable during an annual service. On top of this, it is suggested that you power flush your system every 5 years. Both of these actions will prevent the build of rust and debris inside your central heating.

If you're the reactive type, then you just need to skip to the power flushing stage at this point. You could try this yourself, but on the assumption your radiator is in a bad place at this point, you may want to call in a professional to do this for you. A professional will use a powerful cleaning agent and equipment to flush out the system thoroughly.

If the problem still persists, or your professional advises that you may need a new radiator, you can choose from a wide range of modern and efficient radiators in different styles and colours here at PlumbHQ. This may seem daunting, but this could save you money in the medium term. New radiators are widely accepted to be far more efficient that their older cousins.

3. Check your radiator valves

Your radiator may not be heating up if the valves are in the wrong position, or worse, stuck. A good indicator of this problem is if the radiators nearest to the boiler or upstairs are getting hot, but the ones downstairs or furthest away from the boiler are cold.

In order to diagnose this problem, we'll need to inspect the radiator valves. The TRV is the larger of the two valves, and will have a scale on it. Make sure this is fully open, or at the highest number, when diagnosing this issue. The valve on the other side is the lockshield, and this may also be closed, so open this one up by turning it fully to the left. If you manage to open these valves but still find that only this radiator is cold, it may well be that these valves are stuck.

The easiest way to solve this issue is to buy some new radiator valves and have them installed.

4. Thermostat issues

Another reason you can be left wondering why is my radiator cold is a faulty thermostat can cause your radiators to not heat up properly, or not heat up at all. The thermostat is there to detect the temperature around your home so, if you notice that some rooms in your home are colder than others, it could be a sign of a faulty thermostat. To check if your thermostat is the problem, start by checking the batteries. Low batteries can cause a thermostat to malfunction and fail to signal the boiler to heat up the water.

If the batteries are not the problem, it's best to call in a heating engineer to diagnose and repair any issues with your thermostat. A professional can identify the cause of the problem and provide an effective solution. In some cases, the thermostat may need to be replaced if sensors have failed or it's otherwise beyond repair.

5. Boiler pressure is too low

If you have a combi boilers, your heating system will work on a closed-loop system, meaning that they are pressurised to between one and two bar. So if your boiler is not properly pressurised, it will not provide the necessary hot water to warm your house, which can result in your radiators not letting off any heat.

You can check your boiler's pressure by looking at the dial on the boiler. There is usually a simple colour dial, and if you find that the pressure is too low, you can turn the top-up valve to increase the water pressure, enabling the required amount of water to enter the system. However, it's essential that you don't add too much, as this can lead to other problems and potentially damage your heating system.

In some cases, you may find that your boiler's pressure keeps dropping, even after topping it up regularly. This could indicate a more significant issue, such as a leak in the system or something worse. In such cases, it's best to seek the help of a qualified heating engineer who can diagnose and fix the problem.

6. Faulty pump

A broken pump can indeed be the cause of your radiators not letting off any heat. The pump is responsible for circulating hot water through your heating system and into your radiators. If it is broken or faulty, your radiators won't be able to receive the hot water they need to heat up.

In some cases, you may be able to detect a faulty pump by the sound it makes. So locate your boiler, put your ear to it when the heating is on. If you hear any unusual noises coming from your pump, such as rattling or grinding, it could indicate a problem. However, it's not always easy to diagnose a faulty pump, and you may again need the help of a professional.

Replacing a faulty pump is not a job that you should attempt on your own. Working with the central heating system can be dangerous, and if you're not sure what you're doing, you could cause more harm than good. A professional heating engineer will have the knowledge and experience needed to diagnose the problem and replace the pump safely.

7. Boiler issues

Finally, if none of the above solutions work, the issue may be with other parts of the boiler that we mere mortal can't get to. In this case, you'll need to face the music and call in a heating engineer to diagnose and repair the problem.

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