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Sentinel X100 Central Heating Inhibitor 1 Litre

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Sentinel X100 Central Heating Inhibitor 1 Litre

A 1-litre leave-in inhibitor that protects central heating systems from limescale and corrosion, treating up to 100 litres of system water.

At a glance

Manufacturer part no.
X100
Showing prices

£15.42

£12.85 ex. VAT · VAT at 20%

In stock
Cut-off passed — dispatches next working day
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Same-day dispatch

Ordered by 4pm Mon–Fri, 10:30am Sat.

30-day returns

Unused, in original packaging.

What it is

Sentinel X100 is a leave-in liquid inhibitor for central heating systems, formulated with TripleTech anti-corrosion technology to protect against limescale and corrosion across multiple system metals. It is pH neutral and suits hard, soft and artificially softened water, and is Energy Saving Trust recommended for maintaining system efficiency.

Signs this part needs replacing

  • Black or discoloured water when bleeding a radiator
  • Banging or kettling noises from the boiler heat exchanger
  • Cold spots at the bottom of radiators (sludge/scale build-up)
  • Boiler cutting out on overheat or losing efficiency
  • System recently drained, flushed or had a part replaced without re-dosing

Before you order

  • Confirm your system is open-vented or sealed and whether it contains aluminium components
  • Use a test kit to check existing inhibitor levels before topping up
  • Re-dose after any drain-down, power flush or major repair
  • Isolate the relevant valve or cistern before dosing

Not sure which part?

Search by part number, product name or brand — our technical team confirms fitment before anything is dispatched.