Boiler Noise Silencer F2 is designed to reduce boiler noise and kettling and restore heat transfer capability. Boiler noise is a symptom of a scaled system caused by limescale forming on the inside of the pipework. This product is ideal for use with all types of boilers and is compatible with all metals and materials commonly used in systems including aluminium. The Fernox Express range uses Barrier Pressure Pack technology and compressed air propellent to expel the product so the entire range is non-flammable. The propellent (compressed air) is not mixed with the active product so there is no risk of air ingress into the system which could accelerate future risk of corrosion.
A single dose treats a larger sized property with a heating system of 130 litres, up to 16 radiators or 250 sqm of underfloor heating and can be dispensed directly into a radiator air vent, system filling loop, or via a TF1 Filter using the appropriate adapter supplied with the product. Fernox Express takes less than 30 seconds to dose the system without the need to drain down the system, saving time on-site. If dosing via a TF1 Filter, the filter should be emptied of any collected contaminants prior to treating with the product. Too much treatment will not cause problems and is preferable to insufficient dosing. Severe noise may require more than one application. For long term protection against the effects of corrosion and limescale we recommend systems are cleaned using Fernox Cleaner F3 Express and inhibited with Fernox Protector F1 Express. In single feed indirect cylinders, e.g. ‘Primatic’ or similar, potable water chemicals must be used.
Fernox Boiler Noise Silencer F2 Express is supplied in 400 ml aerosol cans with a universal applicator set.
Fernox Boiler Noise Silencer F2 Express is classified as non-hazardous, but as with all chemicals, keep out of reach of children. In case of contact with skin or eyes; rinse immediately with plenty of water.
Colour: Pale beige
SG: 1.05 @ 20°C
Single Unit Dimensions
Single Unit Barcode
Outer Carton Dimensions
Outer Carton Barcode (ITF)
95 × 66 × 218 mm
241 x 178 x 339 mm
Make sure the system is turned off and allow radiators to cool down (1). Select a radiator and shut both the wheel-head and lock shield valves (2). If a thermostatic radiator valve (TRV) is fitted, close it by turning it to the minimum setting.
Having removed the air vent pin using a cloth to absorb any escaping water (3). Screw the Fernox Express injection nozzle into the air vent (after cutting to the right diameter to fit tightly (4)). Fit the tube to the adapter and screw onto the canister. Attach the other end of the tube onto the nozzle in the radiator (5).
Re-open the wheel-head valve (6) (or TRV) and inject all the content of the Fernox Express by squeezing the trigger for 30 seconds (7). After the product has been dispensed close the wheel-head valve (8) (or TRV), remove the injector nozzle and tighten the air vent pin (9). Open both radiator valves, turn on the central heating system (10) and let it run for 15 minutes to allow the Express to disperse around the system.
Fernox Express can also be for dosed via the system filling loop using the appropriate special adapter supplied with the Express product as well as via the bleed valve on a fitted Fernox TF1 Filter. The whole process takes less than two minutes.
Boiler noise is usually the result of limescale deposition within the heat exchanger of a boiler. This condition is worsened if magnetite is also present in the system, as this combines with the limescale to form a much harder deposit.
Boiler noise is usually the result of limescale deposition within the heat exchanger of a boiler. This condition is worsened if magnetite is also present in the system, as this combines with the limescale to form a much harder deposit. Other sediment forming debris such as sand and brick dust entering the system during installation can also become part of the hardened deposit. Local water conditions also play an important part, particularly the scale-forming solids dissolved in the supply water.
Boiler noise is directly related to the rapid condensation or implosion of steam in water. Localised boiling develops on the surface of the deposit, and small steam bubbles are created that make a rattling noise as they leave the surface and travel around the system.
When installed into existing systems, new boilers can become excessively fouled soon afterwards by oxide sludge present in the system water. Replacing a boiler can disturb soft sludge and loosen sediment in other parts of the system, causing these contaminants to be transported by the system water and re-deposited in the new heat exchanger.
The same phenomenon can occur as a result of circulator replacement if flow rates change. The risk of sediment and sludge deposition in new boilers can be avoided by cleaning the system as part of the installation process. Guidance on correct cleaning and treatment can be found in BS 7593:2006 Code of Practice for Treatment of Water in Domestic Hot Water Central Heating Systems.
What should be done?
Fernox Boiler Noise Silencer F2 is specifically formulated to significantly reduce boiler noise by reducing the surface tension of the system water. The reduced surface tension prevents large bubbles from being able to form and so the associated noise is greatly lessened. Fernox Boiler Noise Silencer F2 efficiently treats the effects of a noisy boiler until the causes can be treated with a full clean of the system.
Fernox DS40 Descaler and Cleaner selectively dissolves scale deposits without attacking the metals commonly found in central heating s62486ystems. However this acid-based cleaner should only be used in new installations or in systems less than 10 years old.
Older systems that have been untreated for periods of time may have existing leaks that are temporarily plugged with corrosion debris. Installations with a history of radiator corrosion failures should not be acid cleansed, as other radiators are likely to have deep corrosion pits or complete perforations.
Older installations can be substantially improved, however, by dispersing the sludge with Fernox Cleaner F3 or Fernox Fernox Powerflushing Cleaner F5, followed by powerflushing with plain water.
After removing all soft sludge from older installations, separate boiler de-scaling may be helpful to resolve the problem. In order to do this, all the radiators should be isolated after which the system can be descaled with Fernox DS40 System Cleaner over a period of time – up to 24 hours. This process should be followed by neutralisation with Fernox System Neutraliser before powerflushing with plain water.