how to check and maintain your radiators

Heating Advice: How to check your radiators

Even though it’s summer, now is the best time to check your radiators are working properly ahead of autumn and winter.

When the temperatures drop and nights draw in, you want your heating to work efficiently and as you expect to keep your home warm and cosy. To do that, you need to do some important checks and carry out some maintenance.

To make sure your heating is ready for the upcoming season, Plumbworld has picked out some important tips you need to know. From valves to bleeding your radiator and useful checks, we’ll cover as much as we can to ensure your radiators are good to go.

Read on to find out more about radiator maintenance and checks ahead of winter…

Radiator Maintenance

Radiators have been around for decades, with some even lasting this long. However, they provide consistent and comfortable heating. Radiators keep interiors warm without the dry heat of warm air heating, and the systems last for a long time. Radiator maintenance doesn’t take long but it’s important to make sure your system is running efficiently.

DuraTherm Horizontal Oval Tube Single Panel Designer Radiator - 600 x 1020mm White

Radiators are very easy to care for, requiring some basic seasonal maintenance to keep them running for years. It’s always best to do your maintenance in the summer for a number of reasons. Firstly, so you can see what is and isn’t working well ahead of when you’ll need it. Secondly, because plumbers will often be more available at this time of year.

There are two main issues and fixes for radiator maintenance...

Why is my radiator cold?

There are few things nicer in autumn and winter than waking up or coming home to a warm house when the weather is cold and crisp. 

DuraTherm Traditional Colosseum Triple Bar Column Radiator - 600 x 828mm Anthracite

However, if you have discovered that your radiator stays cold, you may well need some help. As well as leaving you shivering, radiators that fail to heat up can also indicate problems such as debris in the system causing blockages or a poor system set up.

A radiator may be cold for a number of reasons, but there are also some fixes, which we’ve outlined below:

  • Boiler: Check your heating to make sure that it is in the right setting and working properly. If you have a combi-boiler, check that it’s set for hot water and heating and not - if you have one - in ‘summer mode’. You should also make sure there is no fault code displaying. A fault code may be a little more complicated to deal with.
  • Pump: If your heating has a heat pump, ensure that it’s working. If the pump has stopped working, it will no longer heat the water needed to keep radiators warm. It will result in all radiators losing their temperature. The simplest way to check if your heat pump is working is to see if it’s making any noise.
  • Air in the system: If one or more radiators in your home are cold, this may be a sign there is air in the system. Air in the heating tends to gather at higher points - the top of the radiator - and prevents the distribution of water.
  • Valves are stuck: A cold radiator can often be caused by a stuck valve. This is usually the case if the problem is with just one radiator. The thermostatic valve, the white one that controls the flow of water, can become seized. This can be due to age.
  • Water pressure: If your boiler and pump are working, your water pressure may be at fault. For residential gas boilers, the correct pressure is usually around 1.0 bar. This is often indicated on the gauge and you may need to balance your system to fix it.

How to balance a radiator

DuraTherm Traditional Colosseum Double Bar Column Radiator - 600 x 828mm White
  1. Turn off your heating: to begin balancing radiators, they must be completely cold so turn off your home heating.
  2. Work with your valves: balancing your radiators involves having the correct lockshield valve access. So, you need to get that valve cap removed.
  3. Open your valves: once your valves are exposed, open them up in an anti-clockwise direction.
  4. Turn your heating up: with your radiator valves open, switch the heating back on and turn it up. Make note of the speed at which your radiators take to heat up. Radiators nearest the boiler will warm up the fastest. Measure the radiators and how quickly they heat up.
  5. Turn off your heating again: turn everything off again and let your radiators go cold.
  6. Fastest heating radiator: turn the heating back on. Go to the radiator that was quickest to heat up. Close its lockshield valve in a clockwise direction and then open it by one-quarter turn.
  7. Measuring the temperature: with the fastest radiator warm, take a couple of temperature readings using your digital thermometer. First, from the pipework next to the valve. Then, from the pipework on the opposite side by your thermostatic valve. Record the difference.
  8. Open the lockshield: open your lockshield valve until the temperature difference between the two points is 12°C.
  9. Do the rest of your radiators: once you’ve balanced your first radiator, do the same for the remaining radiators. Do so in the order of their warm up ranking. For the slowest radiator, you may find the lockshield valve even needs to be opened completely.

How to bleed a radiator

DuraTherm Horizontal Oval Tube Single Panel Designer Radiator - 600 x 1200mm White
  1. Switch off the heating: keep your radiator intake valves open, but make sure you turn off your heating
  2. Wait for your radiators to cool: feel all over your radiators to check they’re cool and don’t attempt to bleed them if they’re still warm. You don’t want boiling water to come out when you open the valve and it’ll let your radiator's contents settle.
  3. Equipment: get a radiator key, a cloth, old towels to put down and a container to catch any liquid.
  4. Find the bleed valve: the valve will be at the top of the radiator on one side and will look like a round hole with a square inside. Put your old towels down on the floor underneath it with the container on top to catch any water.
  5. Loosen the bleed screw: with a radiator key, or flathead screwdriver, turn the bleed screw anti-clockwise. One quarter or half turn is enough. Never open the valve fully to avoid water pouring out.
  6. Wait for the hissing to stop: once all the air has been released, the valve will start to leak water. This will need to be mopped up. A steady stream of water is the sign that all the air has gone.
  7. Re-tighten the valve: use your radiator key or screwdriver to re-tighten the bleed screw in a clockwise motion.
  8. Turn on the heating again: turn the heating on and check your work.

Radiator Maintenance Tips

After the other points we’ve been through, there are just a couple more handy tips you should try throughout winter to make sure your heating is running smoothly in autumn.

Turn on your radiator valves

Whether you have normal or thermostatic radiator valves, you need to pay attention to them during summer - even if you aren't using your central heating.

DuraTherm Horizontal Single Flat Panel Designer Radiator - 600 x 1212mm Anthracite

Valves, especially thermostatic valves, react to room temperature and will close themselves off as we move from spring into summer - as they are supposed to do. However, you may have switched your valves down to low or off. This is often the case in summer when central heating is off with valves also completely closed.

You might find when you come to use your heating again that your valves have got stuck in the off position. This means your radiators won't warm up properly or be as hot as they should. Therefore, you or a plumber will need to free up the pin inside the valve.

An easy fix is to turn your valves to their maximum position or setting and then switch off your heating. Your heating will be off so you won't be getting unnecessarily hot in summer, but it means when you do switch it back on in autumn, your valves will be working properly.

Turn your heating on

Calm down, we don’t mean to whack the heating up in the middle of summer but just for up to 20 minutes every three or four weeks.

DuraTherm Horizontal Single Flat Panel Designer Radiator - 600 x 1440mm White

One of the main causes of boiler problems is due to inactivity. You can prevent this by briefly switching your heating on once a month throughout summer.

By doing so, you'll help to keep components of your heating system moving. This way, they will be ready to use efficiently when the temperature drops. If you don't try this trick, it’s possible that your heating will be off for three or four months without moving.

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Don’t forget to check out the rest of our blog for more bathroom advice…

How to fit a Shower Enclosure | How to Fit & Replace a Radiator | Design Inspiration: Contemporary Bathroom Design Tips


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