How to replace an old, rusting Radiator
There are several reasons for removing and replacing radiators that aren’t working properly, most often age and wear and tear will lead to corrosion and poor heating performance, and fitting new units will help to reduce your energy cost by ensuring that your home is being heated efficiently
Replacing a new radiator isn’t a difficult task, and by following our simple guide almost anyone can swap out an old inefficient unit for a new one without too much hassle or mess.
Parts and Materials Required
- Radiator fixing kit and brackets:
- Wall plugs
- Radiator to wall connectors
- Screws, bolts, and washers
- 1-OFF Endcap
- 1-OFF Bleed cap
- TRV and Lockshield
- PTFE Tape
- Insulation Foil
When you purchase a new radiator most of the parts to attach the radiator to the wall will be included, I recommend using Stelard radiators as they are a good quality make and include everything you need to fit but check the pack before you buy and make sure the fittings are included.
I never use the screws supplied with a fixing kit, I find that they are often very cheap and can break on installation, So I use separate fixings and this will depend on the construction of the wall the radiation is to be fitted to.
You can check out our article on the different types of fixings for more information on how to select the right type of wall plugs and screws depending on the type of wall you have.
In this article, we’ll include information on how to fix the radiator to a typical solid brick wall.
Things to Check Before You Start
There are a few things to check before you start. The first is to check the condition and construction of the wall you are going to mount the radiator on.
If there are any cracks or of the wall surface or plaster is in poor condition, if this is the case allow time to make any repairs, in addition, once the old radiator has been removed it’s a good idea to apply a fresh coat of paint.
Measure the existing radiator, height, length, and depth, check the distance between the feed and return pipes and the height from the floor. You can use this information when choosing a replacement.
Confirm how your walls have been constructed, are they solid masonry ie made from bricks or blocks and mortar or using stud and plasterboard – normally tapping on the surface of the wall will give an indication if it is solid or if there is a hollow space behind either a drywall or stud wall.
Solid masonry walls are easier to work with and allow for a wider choice of replacement radiators. Masonry walls are stronger which allows using any size or style or radiator and are not limited to the same weight restrictions as stud walls. By using the correct fixings, generally large radiators can be installed on any part of the wall.
To mount radiators to plasterboard walls, first, you will need to identify where the noggins or studs are located, the best way is by using a digital stud detector which is held against the wall and lets you know where each stud starts and finishes
Wall studs and noggins are the vertical and horizontal timbers that form a frame to support the plasterboard, which is attached by screws or nails. Studs are the strongest part of the wall, and you will need to use them for supporting the radiator.
The position and location of the wall studs can restrict the size and shape of the radiator you can use. When fixing a bracket to a wall stud a normal wood screws of the correct size is all that is needed, wall plugs are not required.
How to remove and replace your radiator
The simplest way to change a radiator is to use like for like. Measure the original unit as described above and choose a replacement that has the same mountings and inlet to outlet centres. For a smaller or larger replacement, the feed and return pipe will need to be modified to suit, you can find out more about extending plumbing in our article or contact a plumber to change these for you.
Replacing an identical radiator which has the same pipe centres is much easier, first turn off the central heating and isolate the radiator by shutting off the radiator valves at both ends. There are several types of radiator valves, they generally work in the same way, by turning the top of the valve clockwise until it won’t go any further.
For thermostatic valves, turn them down to zero or the locked position, for lockshield valves, carefully remove the plastic cover (they tend to split if you are not careful) and turn the square shaft clockwise with an adjustable spanner sometimes a radiator bleed key will fit the square shaft.
It’s a good idea to make a note of the number of turns, this way when you replace the radiator you reset the flow to be the same.
Put down some old rags or newspaper and place a small tray beneath the valve, this will catch the water as it drains out. I like to use an old ice cream tub or a paint roller tray as they are low enough to fit under most pipework.
I always have a spare container and an empty bucket next to me, this allows you to empty the radiator quickly without stopping to empty the old water.
Make sure both valves are turned off, then use a spanner to loosen one of the swivel nuts that connect the valve to the radiator. I often use a pair of plumbing grips or joint pliers to hold the valve in place, this stops it from turning and prevents any damage to the connecting pipework.
The valve joint may need to be cracked at first to allow the water to flow, I use the soft-grip handle on a screwdriver to push the valve away from the radiator, be careful not to loosen the valve nut too far as water will flow very quickly and flood your catch tray.
With the valve joint loose, you can then open the bleed valve at the top of the radiator, this will allow air into the radiator and prevent a vacuum from forming inside the radiator which will stop the water from draining.
The small bleed screw can be loosened using a radiator bleed key or sometimes a flat head screwdriver.
When your catch tray is almost full, close the swivel nut to stop the water and swap for a new tray, then empty the old water into your bucket.
This is where most spills occur and you need to have an old cloth at hand to clear up any spillage. Continue with this process until all the water has been drained from the radiator.
Disconnect the valve at the other end of the radiator and carefully lift the radiator off the wall brackets, try to tilt it slowly to drain any remaining water, as the level drops you will see black sludge draining out, these are the metallic deposits known as magnetite and come from the corroding metal parts of your heating system.
For larger radiators, it’s best to get some help to lift the radiator as they can be heavy and tricky to tip. Once the radiator is empty stuff some old rags into the outlet to prevent any leaks or drips and place the old radiator to one side.
Measure the distance between the bracket and check against the mounting lugs on the new radiator. More often than not they won’t be the same and the old brackets will need to be removed.
Unscrew the fixings from the wall and remove the old mounting brackets, you can fill any gaps or holes if they are not going to be covered by the new radiator mounting brackets.
Use a Stud/Cable/Pipe detector to check if there is anything behind the radiator before you drill any new mounting holes. A digital multipurpose detector is easy to use and it can identify if there are studs, pipes or cables buried in the wall you are about to work on.
By simply holding the detector against the surface, setting the detection depth and then moving the unit from left to right, it should beep and tell you if there are any hazards to work avoid.
Mark out the centre of your radiator and then measure the hole centres had the height for the brackets, check the positions are level.
Often new radiators will have a template you can hold august the wall to mark the position required, I use some masking tape to hold the template in place whilst I mark the hole centres
Then using a hammer drill for masonry walls drill the new holes for wall plugs I have been using Hikoki tools for some time and my 18V combi drill allows me to hold a vacuum cleaner in one hand, just below the drill to catch any dust whilst drilling into brick.
Then gently tap in the wall plugs using a hammer and then Fit the brackets to the wall. Before I fit the brackets I cut and fit some reflective insulation to the wall, this helps to reflect the heat into the room and improves the efficiency of your heating.
Ensure the brackets are fitted the right way round, they often have a short and a long edge, which allows the radiator to sit closer or further away from the wall.
Fit the radiator pipe fitting, first warp some PTFE tape around the thread, hold the fitting in your right hand and the tape in your left then wrap the tape clockwise around the threads, this will mean the PTFE will grip the radiator threads and seal the joint, wrapping the other way will unwind the tape as you screw the fitting in.
Tighten the fittings using either an adjustable spanner or Allen wrench, take care not to over tighten these fittings as you can crack the radiator casting.
Reconnect the feed and return pipework using a spanner and plumbing grips to hold the valve. I like to smear some Fernox LS-X sealing compound on the olive before I make the joint this helps seal the joint.
Then Close the bleed valve and reconnect the water piping and valves before switching on your water supply.
keep the rags and newspaper under the new joints for a little while to ensure no drips fall onto the flooring below.
The new radiator unit can then be refilled and the air bled out. Check out our article on how to bleed radiators for more details on this process.
Find out more about central heating and plumbing in our other great Plumbing articles
This article was written by: Richard Quinton – The DIY Help Desk Owner, Engineer & technical specialist.
Richard is one of the key partners in The DIY Help Desk team. He is a qualified Engineer, writer, and publisher, educated to Master’s level. He is a keen advocate of DIY and home improvements.
Richard enjoys helping others to learn new skills and reach their goals and believes that passing his knowledge and experience on through his writing is an effective way to positively impact the lifestyles and well-being of others on a larger scale.