Fix Your Radiator: How To Fix The 5 Most Common Problems

There’s nothing more annoying than returning home on a freezing cold day to find that your radiators are not working properly, but it’s important not to panic. Radiators can develop a range of common faults, many of which can be fixed easily and inexpensively. You may even be able to get to the root of the problem and rectify your radiator issues yourself, depending on what’s causing your radiators not to work.

Below, we’ve listed the 5 most common radiator problems and shared advice on the best course of action to take when faced with these particular issues.

1)Radiator is cold at the top

If one (or more) of your radiators is cold at the top but warm at the bottom, it’s highly likely that there is trapped air in your radiator. This is a very common problem and usually makes itself known when you first turn your heating back on once the summer is over. Removing the trapped air is as simple as bleeding your radiator, which can be done using a radiator bleed key. If you don’t own a key, you can buy one from your local DIY store.

Here is a simple step-by-step guide on how to bleed your radiators:

• Before you bleed your radiator, make sure your central heating is switched off and the radiator is completely cool.
• Locate the bleed valve, usually found at the top left or right of your radiator.
• You’ll need to open the valve slightly (not fully) using the bleed key, making sure you turn the screw anti-clockwise until you hear hissing, which is the sound of the trapped air escaping. It’s a good idea to hold a cloth beneath the bleed valve when doing this so that you can catch any water that escapes.
• When the hissing stops and a steady stream of water appears from your radiator, turn the key clockwise to close the bleed valve.

Just be sure to check the pressure of your boiler gauge before turning your heating back on, as the pressure may need to be rebalanced.

2) Radiator is cold in the middle or at the bottom

Unfortunately, a radiator that is cold in the middle or at the bottom but hot at the top is a trickier problem to fix. The most likely cause of this is a build-up of sludge, which may be blocking the middle or bottom area of your radiator and preventing that section from heating up. To correct this, you’ll need to flush out the sludge that’s living inside your radiator. The easiest way to remove the sludge is to call in a professional to carry out a power flush. Having said that, you can purchase a sludge remover to flush out the system yourself, provided that you have an unpressurized and tank fed open-vent system. If you have a pressurized system, you will have no other option than to get help from a Gas Safe engineer.

3) Radiator is not heating up at all

If only one of your radiators is refusing to heat up, you could have a stuck or frozen thermostatic valve, which prevents water from getting into your radiator. The thermostatic valve is usually situated beside the base of the radiator and can seize up when it starts to get old. To get to the bottom of this issues, you’ll need to remove the top part of the valve to reveal a pin. Then, use your finger to put a little pressure on the pin to see whether it’s able to move freely. If it won’t move, you can try and loosen it with your finger and a squirt of grease or WD40. Should this not work, you must contact a qualified heating engineer to replace your thermostatic valve.

4) Radiator is leaking

There are a number of issues that can cause a radiator to leak, such as corrosion or a leaking valve. You can use a towel to dry the surface of your radiator and the valves to determine where exactly the leak is coming from. Once dry, look for the section of the radiator that stays wet, as this will be the problem area.

If you discover that the valve is leaking, this is the easiest thing to put right. A leak can occur when the valve has been left in the mid-open position, so check this first. If the valve needs repairing, you must follow these steps in order:

• Drain the system and turn off the supply valve and lockshield valve.
• Place some towels under the leaking valve before unscrewing the union nut which connects the radiator and water pipe.
• Open up the bleed valve to release the remaining water from the radiator (you may need to use a bucket to catch this water).
• Once the radiator is empty, tightly wrap some PTFE tape around the valve tail, then re-tighten the union nut and re-open the bleed and lockshield valves.
• Finally, check for leaks once the system has re-filled and before you close the bleed valve. If the leak persists, you’ll need to replace the valve.

Corrosion is also a common culprit of a leaking radiator and it’s an issue that can’t be rectified. So, if the leak is caused by corrosion, you’ll need to purchase a replacement radiator.

5) Radiator is making unusual noises

You might hear a ticking sound every now and then, which is quite normal as your radiator will do this when it’s heating up or cooling down. If the same sound can be heard from under the floor, this will be your pipes expanding and, like your ticking radiator, needs no attention.

Sometimes, your radiator may make a whistling noise when the water flow rate is too low or too high. To stop this, turn the radiator valves fully on.

When you can hear tapping or banging sounds, you should bleed your radiator as this is usually caused by trapped air (see problem 1 to find out how to bleed your radiator). If this doesn’t work, you’ll probably need to call out a Gas Safe engineer to get to the bottom of your noisy radiator issue.

REMEMBER:Although some minimal risk problems with radiators do not require professional assistance, you must never try to resolve major issues yourself as this is dangerous and could cause costly damage to your property. Don’t forget, you can also seek help from a qualified heating engineer if you would rather not carry out simple tasks (such as bleeding your radiators) yourself.