There are several reasons why you might need to remove or replace a radiator. You might need to drain it of the sludge build-up inside, or perhaps decorate behind it. Removing and replacing a radiator will probably be a messy job, but it doesn’t need to be a difficult one and it doesn’t mean you have to drain the whole system. Read our guide to Common Central Heating Problems to learn some of the reasons why you might need to remove a radiator.
Step 1 – Removing the Radiator
Turn the heating off before you start, and allow it to cool completely. As mentioned above, this is likely to be a messy task, so the first thing you need to do is prepare for that mess. Lay polythene sheets below and around the radiator and place old towels directly under the valves. You will also need a couple of bowls to catch any leaking water, so find some which fit underneath the radiator and valves.
Shut off the Control Valve (the knob that controls the temperature of the radiator) and then remove the plastic cover from the Gateshield Valve (the valve at the opposite end of the radiator to the control valve). This will reveal a small square nut that needs to be tightened using a pair of pliers or a small spanner. Count the number of turns it takes to close the gateshield valve and write the number down.
Slide your bowl under the control valve and use an adjustable spanner to undo the Union Nut (the nut connecting the radiator to the valve). Water will then drain out of the radiator, so make sure your bowl is in place. If you are using a small bowl, it might be worth having another on hand in case the first fills up. You can open the air vent at the top of the radiator to speed up the flow of water if needed.
When the water stops flowing, move to the opposite end of the radiator and place another bowl under the gateshield valve. Undo the union nut between the radiator and the gateshield valve and be prepared for some more water to leak out. When all the water has stopped leaking out, plug both ends of the radiator with some absorbent paper or cloth.
You can now carefully lift the radiator off of its brackets and move it outside. Prop the radiator up against a wall, with one end raised higher than the other, and remove the paper plug from the low end. This will allow any built-up sludge inside the radiator to slowly leak out. Very new radiators probably won’t need this.
Step 2 – Replacing the Radiator
With the radiator plugged at both ends with absorbent paper or cloth, carry it back into position and lift it onto the wall brackets. Remove the plugs and reconnect the union nuts to the control valve and the gateshield valve. Make sure they are tightened properly but be careful not to twist or bend the pipe as you do so.
Open both valves to let the radiator fill up, opening the lockshield valve by the same number of turns it took to close it. Open the air valve at the top of the radiator to let the air escape. As soon as the water starts to dribble out of the air valve, shut it off tightly. Check for leaks around the air valve, control valve, gateshield valve, and the union nuts. If any of them leak, tighten them slightly.
Step 3 – Fitting a New Radiator
If you are replacing the old radiator with a new one, but are planning to reuse the valves, you will need to remove the tail pieces from the old radiator by turning them anti-clockwise with an adjustable spanner. You will also need to check to see if the old brackets are in the right position for the new radiator and if not, re-fit them in the correct position.
Clean the threads of the tail pieces you took out of the old radiator and then wind PTFE tape around them. Screw the tail pieces into the holes at the bottom of the new radiator. Remove, clean, and fit the air valve from your old radiator into your new one in the same way. Use PTFE tape and a radiator spanner to create a tight seal. If the new radiator has an open tapping at the opposite end, fit a new plug tightly into the hole (these can be bought from DIY stores or plumbing merchants).
Lift the radiator onto the brackets and connect the valve union nuts to the tail pieces on either end of the radiator. Open both valves to let the radiator fill up, opening the lockshield valve by the same number of turns it took to close it. Open the air valve at the top of the radiator to let the air escape. As soon as the water starts to dribble out of the air valve, shut it off tightly. Check for leaks around the air valve, control valve, gateshield valve, and the union nuts. If any of them leak, tighten them slightly.