Make sure the system is turned off and allow radiators to cool down. Select a radiator and shut both the wheel-head and lockshield valves. 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, screw the Fernox Express injection nozzle into the air vent after cutting to the right diameter to fit tightly. Fit the tube to the adaptor and screw onto the canister. Attach the other end of the tube onto the nozzle in the radiator.
Re-open the wheel-head valve (or TRV) and inject all the Fernox Express by squeezing the trigger for 30 seconds. Then close the wheel-head valve (or TRV), remove the injector nozzle and tighten the air vent pin. Open both radiator valves, turn on the central heating system and let it run for 15 minutes to allow the Express to disperse around the system.
Not only can the Fernox Express be dispensed directly into the radiator it is also ideal for dosing via system filling loop using the appropriate special adapter supplied with the product. The whole process takes less than two minutes.