Can You Replace a Radiator Yourself?

Posted: Friday, June 19, 2020

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Rathmell 4 column cast iron radiator

change a radiator, is it easy to change a radiator

If you’ve been browsing our stunning cast iron radiator range, you may be wondering - is it easy to change a radiator?  If it’s time for an upgrade, you can use this handy guide to learn exactly how to change a radiator and what tools you’ll need. You can then decide whether to take the job on yourself or whether it’s best to hire a plumber!

How Easy Is It to Change Radiators?

Difficulty: Medium

If you want to change a radiator, it’s fairly straightforward. The task will take a couple of hours so long as you know what you’re doing. The easiest way to replace a radiator is like-for-like. This means your new radiator is the same size as your old one, rather than buying exactly the same model. 

Once you know how to change a radiator it will involve a little elbow grease and skill, but it should be achievable if you’re a competent DIYer. If you don’t feel confident with the task ahead, we advise calling in a professional as you could end up with some messy water damage to your carpets and wallpaper if the job goes wrong!

Do You Need a Plumber to Change a Radiator?

Is it easy to change a radiator? That depends. You may feel confident changing a like-for-like model, but if you’re purchasing something different, you may need to make adjustments to your pipework. Plumbers know how to change a radiator and will complete the job nice and quickly, without any head scratching!  

To change a radiator to a larger model, or vice versa, the floorboards underneath your radiator will need to be lifted so that you can access the pipework below. After positioning the new radiator, your pipework needs to be modified to fit your new radiator’s dimensions. You need to be confident in how to change a radiator to avoid mistakes that can lead to troublesome leaks. 

How to Change a Radiator Yourself

Is it easy to change a radiator for a like-for-like model - yes! But you’ll need to know how to go about it…

Measuring For A Replacement Radiator

Your first task is accurately measuring for your replacement radiator. You’ll need to find the ‘pipe centre’ number, which is the distance between the two valves at either end of the radiator. The valves will attach to your pipework so measuring along the top of your radiator won’t give you an accurate reading of what size radiator you need.  

To know how to change a radiator, you’ll also need to pay attention to the depth of the new model. If you choose something that sits further away or closer to the wall, you may face issues when reconnecting it to the pipework. The height shouldn’t make a difference so long as the wall can support its weight. 

Before You Start

Before you change a radiator, always check the condition of the wall it’s attached to. If your current model is hanging on to crumbling plaster, you will need to patch it up beforehand. Also identify where the wall studs, wiring and pipes are positioned within the wall before deciding how to change a radiator for your new model. You can use a digital detector to locate these things, preventing you from drilling into anything hazardous. 

Use plenty of old towels or protective sheets to shield the surrounding area from water damage. You may be surprised at the volume of dirty water that can escape from the valves so this helps to keep your carpets and walls safe from stains. 

Follow these steps to learn how to change a radiator…

  • Isolate the old radiator. 

Your first job is easy - turn off your central heating and water supply. Ensure that your radiator has completely cooled before you do anything else. Next, isolate the radiator by closing the valves at each end. The manual or thermostatic valve will be located at one end. Turn this clockwise until it stops. At the opposite end will be the lockshield valve. Use a spanner to turn this clockwise, taking note of how many turns you make as you will use this information to reset the new radiator to the same position.

  • Drain the radiator. 

The water needs to be released from your old radiator so that you can safely remove it. There will be a connection at each end that looks like a nut. Place a bowl on top of a towel underneath it to collect the water. Using a spanner, turn the nut away from you to loosen it and use a second spanner to keep the pipe coming up from the floor in place. This will prevent any damage. 

The water won’t release straight away as you need to let some air in. Place your radiator key into the bleed valve at the top and turn it clockwise. Water should gradually begin to drip into the bowl but if it fills up too quickly, close the top valve to stop the flow and empty the bowl. Repeat this at both ends of the radiator. Part of learning how to change a radiator is being patient! Draining the water may take a while but it’s advisable to wait until it’s done to prevent dirty water from spilling onto the floor.  

  • Remove the old radiator. 

Before you can change a radiator, the old one needs to be removed! Once the water has drained out, lift the radiator off the wall or off the floor. To do this, you may need to pull the pipes out slightly at the sides, and then lift the radiator upwards. Two people may be needed for this part depending on the weight of your old radiator. 

There will probably still be a little water left inside so carefully tilt the valve into your bowl to remove the last bit. Stuff a rag into the opening to prevent further spillage as you take it out of the room.  

A tip when learning how to change a radiator is to remove the valve tails (the things that look like nuts) from your old model. Once cleaned, you can use these again. Apply around 5 - 10 rounds of PTFE tape to their threads to ensure the seals stay intact. 

  1. Replace the wall brackets before you change a radiator. 

Your new radiator may not be compatible or may have different dimensions from your old brackets. The old ones will need to be removed so the new brackets can be fitted before you change a radiator. If you are learning how to change a radiator for a freestanding cast iron model, you may need to attach a new wall stay instead. 

To replace brackets, measure the distance between the fixtures on your new radiator and the distance from the bottom of the bracket to the bottom of the radiator. Plot these points onto your wall where the new brackets will be positioned and use a spirit level to ensure they are straight. Drill them into place. The bottom valves should align with the pipework in the floor when you change a radiator, so hanging the brackets accurately is essential. 

  1. How to change a radiator. 

Once everything is aligned, place your bleed valve and valve tails back into your new radiator. Either hang it on the bracket or position it on the floor before tightening the nuts to connect it to your pipework. Like step 2, use two spanners to tighten the nut and hold the pipe firmly in place. 

Return your lockshield and control valves that you isolated before draining your old radiator. Use the same number of turns to reopen them. Open the bleed valve a little to expel any trapped air and tightly close it once this is done. When you change a radiator, you’ll probably hear a lot of gurgling as it fills with water. If you don’t hear anything, check that you have opened the valves enough. 

  1. Add radiator corrosion inhibitor. 

When you change a radiator, add a corrosion inhibitor to stop sludge from being produced as a result of water coming into contact with the metal. When you drain a radiator, some of the corrosion inhibitor will have been lost so it needs to be replaced, even if you didn’t flush the entire system out. There are several types available so you will need to research the best product for your central heating system.  

  1. Turn on your central heating. 

Now you’ve learned how to change a radiator, you can sit back and appreciate your work! If you’re sure your connections are nice and tight, turn on your central heating and enjoy the warmth of your new radiator. Is it easy to change a radiator? Tell us once you’ve given it a go!

If you’re looking for a replacement radiator, Trads has a beautiful collection of traditional and contemporary cast iron models. We manufacture radiators in our Lincolnshire factory so you can choose the exact size and finish to suit your room. 

Shop online or contact us if you need more help with how to change a radiator. 

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