Radiator Removal and Installation

If the wall behind only needs a quick coat of paint, a long-handled radiator roller or careful masking is often enough. Full removal makes sense when the wall changes more: new plaster, a skim coat, tiles, wallpaper or internal insulation. When you replace flooring, removal helps most if the floor height changes and the pipes will need adjusting afterwards.

Removal is also the first step when you swap a radiator for a new one. This job assumes the same radiator goes back in the same place. If the type, size or connection layout changes, the work becomes more involved.

The method depends on whether the radiator has working valves on both sides: the thermostatic valve on the flow and the lockshield valve on the return. If both close and seal properly, there is no need to drain the whole system. If they are missing or seized, at least part of the system has to be drained.

1. Switch off the heating and let the radiator cool down.
2. Close the thermostatic valve on the flow and the lockshield valve on the return, counting and noting the turns on the lockshield so it can be reset.
3. Place a tray under the joints and lay down old towels.
4. Loosen the nuts on both joints and drain the water from the radiator.
5. Lift the radiator off its brackets and carry it to a safe place, with two people for larger ones.
6. Fit caps or blanking nuts on the open valves.
7. After the other work is finished, check the brackets, seals and threads and replace worn seals.
8. Hang the radiator back, level it and reconnect the joints.
9. Open the valves slowly, let the radiator fill and check for leaks.
10. Bleed the radiator, check the system pressure and return the valves to their original settings.

Why does the lockshield setting matter? When the system was set up, it was used to balance how much water flows through each radiator. If someone simply closes it and then opens it fully, that radiator can take heat away from the other rooms.

In a house with its own boiler you are in control: you switch off the heating, drain and refill as needed. After refilling and bleeding, the pressure usually drops, so it has to be topped up at the boiler to the level the boiler manufacturer gives. If the system was drained, it is worth checking that the corrosion inhibitor is topped up too. Leave the boiler itself, especially a gas boiler, to a qualified, registered gas engineer. If you ever smell gas near the boiler, leave the room straight away and call the local emergency number or 112.

In a block of flats the radiator is often part of a shared heating system. Before anything is removed, contact the building management or owners' association. If the radiator has no working isolation valves, draining the riser is arranged by the management or a company they appoint, often only outside the heating season. Radiators in shared buildings may also carry a heat cost allocator. It must not simply be pulled off and stuck back on, otherwise heating bills can be disputed. Agree its removal and refitting with a new seal with the management or the metering company.

Temporarily taking a radiator off the wall does not usually need any permission. For a larger heating renovation or changes to the pipework, check with your local building authority which rules apply rather than assuming nothing is required.

How demanding the job is depends mainly on what the engineer finds on site. These make the work easier:

• A panel radiator with a working thermostatic valve and lockshield
• Newer joints that loosen without much force
• Clear access and solid brackets in a sound wall

These make it harder:

• A cast iron column radiator, which is very heavy and often has corroded joints
• Seized or leaking valves that need replacing
• No isolation valves, so the system or riser has to be drained
• A change in wall or floor thickness that means extending pipes or moving brackets
• Loose wall plugs in crumbling plaster or old masonry
• Heavily contaminated system water that clogs the valves

In practice an old valve that is closed for the first time in years often stops sealing properly. It pays to expect this and replace the valve while the radiator is off anyway.

• Radiator not level: it is harder to bleed and air stays trapped in one corner, so check with a spirit level before tightening the joints
• Old seals reused: the joint may hold for a few days and then start to weep, so fit new ones
• Flow and return swapped: the valve may hum or regulate poorly, and the flow direction is usually marked with an arrow on the valve
• Bleeding forgotten: the radiator heats only at the bottom or not at all, so always bleed after refilling
• Lockshield set wrongly: one room overheats while another stays cold
• Radiator too close to the wall: air circulates poorly and dust builds up behind it, the usual gap is a few centimetres from the wall and roughly a hand's width above the floor

Why is the radiator nearly always under the window? Warm air rises and meets the cold air falling from the glass. That is why it usually makes sense to put it back exactly where it was unless there is a good reason to move it.

When you take over the work, spend a few minutes with the heating running and the radiator warm:

• The radiator sits firmly on its brackets and does not move
• It is level and in the same position as before
• The joints stay dry when hot, which you can test by wiping them with a tissue
• The radiator heats evenly across its whole surface, not just at the bottom
• The thermostatic head turns freely and responds
• The lockshield is set as it was originally
• The boiler pressure is within the manufacturer's range
• In a flat, the heat cost allocator is back in place and correctly sealed
• The surroundings are dry and the wall and floor are undamaged

After a few days of use, look under the joints once more. Small weeps often only show after the first few cycles of heating up and cooling down.