X100 Inhibitor X200 Noise Reducer X300 System Cleaner X400 System Restorer X500 Inhibited Antifreeze X700 Sanitiser and Biocide X800 Jetflo Ultimate Cleaner X900 Filter Aid Deposit Remover Leak Sealer Seal X Joint & Leak Sealer

X200 Noise Reducer

X200 Noise Reducer
Safety Information

Sentinel X200 boiler noise reducer is a unique, life-long system treatment for the elimination boiler noise.

Safe to use in all types of indirect central heating systems, X200 noise reducer will quickly pay for itself in reduced fuel usage.

  • Eliminates boiler noise "kettling".
  • Restores boiler efficiency.
  • Safe and non-corrosive.
  • No need to flush - stays in system.


  • 1 litre bottle
  • 10 litre cubitainer
  • 20 litre cubitainer


Sentinel X200 is a non-acid product which has been formulated for the treatment of kettling in central heating boilers caused by limescale. Unlike alternative treatments, Sentinel X200 is added to the system and left there without causing any problems. Sentinel X200 is extremely successful in reducing noise problems caused by the presence of limescale on the heat exchanger surface, and restoring boiler efficiency.

Many noise problems are caused by system design or mechanical faults. It is important to check for these before seeking a chemical solution.

Boiler noise can also be caused by sludge (e.g., iron oxide corrosion debris), in which case, the system should be cleansed with Sentinel X400 System Restorer.





1 litre of Sentinel X200 is sufficient to treat a typical domestic system of up to 10 radiators. Larger systems should be dosed with 2 litres. The time taken for boiler noise to reduce/be eliminated will depend on the hardness and quantity of lime scale present. In extremely severe cases, a further dose of Sentinel X200 may be necessary.

Sentinel X200 should be left in the system. The water should also be treated with Sentinel X100 inhibitor, or Sentinel X500 inhibited antifreeze.




Open Systems: Dose via F&E cistern, via a by-pass feeder or use a Sentinel Dosing Vessel.

Sealed Systems: If the system is empty, add to any convenient point before filling. If full, use a Sentinel Dosing Vessel to inject via the filling loop or other access point.

Physical properties

Appearance: Clear colourless liquid
Odour: Mild
Specific Gravity: 1.02 (20°C)
pH (1% solution): 7.5 (approx.)
Freezing point: -1.5°C

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Can I add Sentinel X200 if Sentinel X100 is already present in the system?

Yes!! Sentinel X100 and Sentinel X200 are entirely compatible with each other. In fact adding Sentinel X200 to the system already containing Sentinel X100 is recommended for best protection!


How does the Sentinel X200 work?

Boiler noise, sometimes called "kettling", is caused by build up of scale on the heat exchanger in the boiler. Uneven distribution of the scale causes localised over-heating of the system water to form steam bubbles that collapse noisily when they reach cooler water. The Sentinel X200 modifies the scale allowing them to be removed and full, even heat transfer returned with no more localised overheating, no more steam bubbles... no more noise!


How long does Sentinel X200 take to work?

The benefits of Sentinel X200 should be obvious almost immediately but it normally takes 2-3 weeks to fully eliminate boiler noise, but can take a little longer (up to 6 weeks) if the boiler is heavily scaled.


I have added Sentinel X200 but the noise is still there, what should I do?

First check with your plumber to see if the noise is caused by other problems such as gas flow rate. It can take 4-6 weeks for Sentinel X200 to be fully effective. If the boiler is still noisy after this time, add another dose of Sentinel X200.


I have added Sentinel X200 and the noise has gone worse!

Sometimes this happens if the Sentinel X200 removes the scale unevenly (which is quite possible if the scale layer is thick). Wait for 4-6 weeks and if it is still worse add another bottle of Sentinel X200. This should clear the scale and stop the noise.


Do I need to flush the Sentinel X200 out of the system?

No, Sentinel X200 stays in the system to provide a long-term cure.


Can Sentinel X200 be used as an offline cleaner for heavy scale build up on the heat exchanger?

No, a stronger chemical needs to be used, such as Sentinel Deposit Remover.


Is Sentinel X200 acid based?

No. Sentinel X200 is a neutral product.

Can I use Sentinel X200 in a Primatic system?



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The information provided below enables compliance with the Control of Substances Hazardous to Health Regulations. A Safety Data Sheet is available upon request.

Sentinel X200
Boiler Noise Reducer for Central Heating Systems

An aqueous solution of synthetic polymers, phosphonate and surfactant

Health Hazards
Not for use in potable water systems
Not considered hazardous to health


Keep out of the reach of children.

Avoid contact with skin and eyes.
Wash out empty container thoroughly with water before disposal

Keep container tightly closed
Store in cool, well ventilated area

Flush spillage with plenty of water and wash to waste

Fire/Explosion Risks

First Aid

Skin Exposure

After contact with skin, wash immediately with plenty of water.

If irritation develops, seek medical attention

Eye Exposure

In case of contact with eyes, rinse immediately with plenty of water and seek medical advice.


Rinse mouth with water
Do NOT induce vomiting!
Seek medical attention

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SESI is a low maintenance, non-polluting device which uses a natural electrolytic process to prevent limescale build up inside pipes and appliances.

By protecting against the build up of limescale, you could help your customers save up to £130 a year on their energy bills.

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Sentinel Performance Solutions Ltd | The Heath Business & Technical Park | Runcorn | Cheshire | United Kingdom | WA7 4QX | 01928 588 330