Helpful video reference. We use Electric Radiators Direct's UK walkthrough, "HOW TO replace storage heaters - 6 simple steps!", as the video reference here. Electric Radiators Direct are a UK electric heating specialist and their guide covers the process clearly, including the points where the weight of the old unit becomes the main challenge.
1. Find and isolate the dedicated circuit
Each storage heater has its own radial circuit, usually from a separate Economy 7 consumer unit or the off-peak terminals on a dual-rate meter board. The MCB is typically labelled "storage heater" or "SH". Switch it off and, if the board has a locking hasp, use it.
Go to the FCU on the wall behind or beside the heater and test for voltage at the load terminals with an approved two-pole tester. Both positions should show dead before you proceed.
2. Photograph the FCU connections
Undo the screws on the FCU cover and pull it away from the mounting plate. Take a clear, well-lit photo showing which terminal holds the brown flex conductor, which holds the blue, and where the earth connects. This photo is your reference for the new unit.
Note the fuse rating stamped on the cartridge inside the FCU. Compare it against the current rating on the data plate of the new heater before you put the same fuse back.
3. Disconnect the heater flex
Loosen each terminal screw and withdraw the flex conductors one at a time. Wrap insulating tape around the bare ends so they cannot touch each other or the mounting plate while you work. Some FCUs have a separate earth terminal on the backplate: disconnect that too.
If the heater has a hardwired connection, no flex and no FCU, stop here. A direct connection to the radial circuit means the work involves the circuit conductors themselves, and that needs a qualified electrician to disconnect and reconnect correctly.
4. Remove the old heater
Storage heaters are dense. A typical unit weighs between 40 kg and 120 kg depending on the brick content and age. You need a second person for this step.
Tilt the unit slightly forward and check for any hidden wall fixings at the back. Older heaters sometimes have a bracket bolted to the skirting or wall. Once clear, walk the unit away from the wall in small steps. If you have a wooden or laminate floor, protect it with a piece of hardboard.
5. Position the new heater
Carry the new unit into position with your helper. Place it against the same wall, centred on the FCU. Most heaters need at least 150 mm clear on each side for air circulation, and the manufacturer's instructions will give the minimum floor clearance if applicable.
Check the unit sits level by looking along the top. If it leans forward noticeably, the castors may need adjusting or the floor is uneven: a leaning heater can develop hot spots on the brick at the back.
6. Connect to the FCU
Run the new heater flex to the FCU. Insert each conductor into the correct terminal: brown (live) to L, blue (neutral) to N, green-and-yellow (earth) to the earth terminal. Push each conductor in fully and tighten the screw until the conductor is firm. Give it a gentle tug to confirm it will not pull free.
Fit the FCU fuse. If the new heater has a higher wattage than the old one, check the fuse rating against the current on the data plate before fitting. Refit the FCU cover and tighten the fixing screws.
7. Restore power and test
Switch the dedicated circuit back on at the consumer unit. Storage heaters will not produce heat immediately: they charge overnight on the off-peak tariff. Set the input control dial to its maximum position to get a full charge on the first overnight cycle.
The following morning, check that turning the output dial releases warm air. If the heater has a manual boost function for immediate heat, test that too. A heater that charges but does not release heat usually points to a faulty output damper, not an electrical fault.
When to call us
A like-for-like heater swap on an existing FCU is well within what a careful homeowner can do. If the old heater was hardwired, if the circuit needs upgrading to handle a more powerful unit, or if you want to add a heater to a room with no dedicated supply, those are jobs that need a registered electrician and a Minor Works Certificate. Richard covers Sandwich and the surrounding area.
Storage heating work in Sandwich?
Richard can assess existing circuits, disconnect and reconnect hardwired units correctly, and certify any circuit alterations with the right paperwork.
Contact Richard