Timeguard FST24 24-Hour Fused Spur Timeswitch

Timeguard FST24 24-Hour Fused Spur Timeswitch

By Timeguard · Model: FST24 · Electrical & Lighting

24-hour mechanical fused spur timeswitch rated at 13A, designed to replace a standard fused connection unit for immersion heaters and storage heaters.

  • 24-hour mechanical timer with 15-minute switching intervals
  • Fused at 13A — replaces a standard fused connection unit
  • Manual override switch for on/off control outside timed periods
  • Fits a standard single back box (35mm minimum depth)
  • Neon power indicator shows when the load is energised
  • Multiple on/off periods can be set within a 24-hour cycle
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Overview

The Timeguard FST24 is a mechanical fused spur timeswitch that replaces a standard fused connection unit, adding 24-hour time control to hardwired appliances. It is most commonly used to control immersion heaters and storage heaters, allowing homeowners to programme heating periods around off-peak electricity tariffs. The 15-minute switching intervals and multiple on/off segments give sufficient flexibility for most domestic heating schedules.

In-Depth Look

The Timeguard FST24 has been a standard fitting in UK airing cupboards for years. It provides a simple, reliable way to put an immersion heater or storage heater on a timer without the need for a separate time clock or smart controller.

How It Works

The FST24 replaces a standard fused connection unit on the wall. Inside, a 24-hour mechanical clock drives a switching mechanism that turns the connected load on and off according to the segments pushed in or out on the timer dial. Each segment represents 15 minutes, so you can programme multiple heating periods throughout the day. A manual override switch on the front allows the load to be turned on or off independently of the timer.

Typical Applications

The most common use is controlling an immersion heater on an Economy 7 or Economy 10 electricity tariff, where hot water is heated during cheaper off-peak hours. It is also used for storage heaters, towel rails, and any other hardwired appliance up to 13A that benefits from timed operation. The neon indicator on the front confirms at a glance whether the load is currently energised.

Verdict

The Timeguard FST24 is a proven, no-nonsense solution for adding timed control to hardwired appliances. Its mechanical simplicity means there are no batteries to replace, no apps to configure, and no connectivity to troubleshoot — just push the segments and let the timer do its job.

Specifications
Timer Type24-hour mechanical
Switching Intervals15 minutes
Fuse Rating13A
Voltage230V AC 50Hz
Back Box Depth35mm minimum
FinishWhite

Who It's For

  • Electricians installing time control for immersion heaters on Economy 7 tariffs
  • Homeowners wanting to schedule storage heater charging periods
  • Landlords adding timed control to hardwired appliances in rental properties

Pros & Cons

Pros

  • Simple mechanical operation with no programming complexity
  • Fits a standard single back box — straightforward replacement for a fused spur
  • 13A fuse rating handles immersion heaters and storage heaters
  • Manual override allows instant on/off control when needed

Cons

  • Mechanical timer is less precise than digital alternatives
  • 24-hour cycle only — no 7-day programming for different daily schedules
  • Timer dial can be fiddly to set in a dimly lit airing cupboard
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