X200 Boiler Noise Reducer

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.

Features and Benefits

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


  • 4 x 1 Gal. case
  • 5 Gal. jug


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.

One quart of Sentinel X200 is sufficient to treat a typical residential system of up to 25 gallons. Larger systems should be dosed at 1% of system volume. 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 dosing vessel.
Sealed Systems: If the system is empty, add to any convenient point before filling. If full, use a dosing vessel to inject via the filling loop or other access point.

Physical properties
Appearance: Clear colourless liquid
Odour: Mild
Specific Gravity: 1.02 68°F)
pH (1% solution): 7.5 (approx.)
Freezing point: 29.3°F

Safety Information

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


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 dose 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 a domestic heat exchanger?
No, another product suitible to de-scale the domestic water side of any AERCO product is AERCO HydroSkrub.

Is Sentinel X200 acid based?
No. Sentinel X200 is a neutral product.

Can I use Sentinel X200 in a Primatic Cylinder?

Technical Documents

Application and Sizing Guidelines

Controlling Aluminium Corrosion

pdf 84.12 KB | December 14, 2015

Water Treatment for Condensing Boilers

pdf 86.88 KB | December 14, 2015

Literature and Performance Data

Water Quality in Hydronic Systems

pdf 194.03 KB | December 14, 2015

X200 Material Safety Data Sheet

pdf 73.98 KB | December 14, 2015

X200 Technical Data Sheet

pdf 85.95 KB | December 14, 2015