Cleaner F3 is an effective, universal pH neutral, non-foaming cleaner, which removes sludge, scale and debris from existing central heating systems to restore heating efficiency and eliminate boiler noise. When commissioning new systems in accordance with local regulations and best practice, Cleaner F3 is ideal to remove flux residues and other installation debris to help extend the life of the boiler and the efficiency of the system. 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.
Cleaner F3 Express will protect a large system (130 litres or up to 16 single radiators) 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 then 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. Additional/ repeat applications of Cleaner F3 Express may be necessary for larger systems, or if systems are heavily sludged.
Fernox Cleaner F3 Express is also designed to be used in conjunction with a powerflushing unit. In this case, please refer to the unit manufacturer’s instructions. When using Cleaner F3 Express with a powerflushing unit, cleaning should be completed within an hour. Use dynamic flushing with plain water until the water is clear, testing with a TDS meter to ensure thorough flushing. Refill the system adding a suitable Fernox Protector for long term protection against corrosion and limescale. In single feed indirect cylinders, e.g. ‘Primatic’ or similar, potable water chemicals must be used.
Firstly, drain and refill the entire system with plain water. For optimum results the entire system, including drop feed radiators, where fitted, should be completely drainable. Preferably full bore gate valves with hose connectors should be provided temporarily for this purpose. Motorised and thermostatically controlled valves must be set, so that no part of the system is closed off during cleaning, or rinsing. Discharges must be made to the foul drain and not the surface water drain. For open vented systems add Fernox Cleaner F3 Express via the header tank. For sealed systems add via a radiator using a Fernox Injector. When cleaning existing systems, sludge and debris should be dispersed for at least one hour at normal operating temperatures. However, to remove hardened iron oxides and limescales, the cleaning time can be extended to up to one week under the normal heating cycle. If a radiator still has a cold spot after one hour, increase the flow through the radiator by closing the valves on the other radiators.
An additional or repeat dose of Cleaner F3 Express may be necessary in some cases. Drain and flush the system thoroughly to remove the cleaning chemical and debris. At least three complete changes of water are likely to be required. This is a crucial part of the cleaning process and must be carried out correctly. Use a rinse test meter such as the Fernox TDS meter to ensure that the Total Dissolved Solids have been satisfactorily removed.
The system can be regarded as being thoroughly flushed when the system water value is within 10% of the mains water value. Differences over 10% mean that significant cleaner residues have been left in the system and further flushing is required. If not removed, cleaner residues will promote corrosion and negate the cleaning process.
Fernox Cleaner F3 Express is supplied in 400ml aerosol cans with a universal applicator set.
Fernox Cleaner F3 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. Wear suitable gloves.
Odour: Faintly aromatic
pH (conc): 6.4
pH (in-use) 6.5 – 7.7
SG: 1.182 @ 20°C
Single Unit Dimensions(Height x Width x Depth)
Single Unit Barcode
Outer Carton Dimensions(Height x Width x Depth)
Outer Carton Barcode (ITF)
218 × 66 × 95 mm
241 x 178 x 339 mm
Fernox Cleaner F3 should ideally circulate around the system for at least one hour, or up to a week, after which it should be drained out and the system flushed/ cleaned before adding Fernox Protector F1 or Protector + Filter Fluid together with a Fernox TF1 Filter to protect the system from further corrosion and scale formation.
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.