Can Fernox Leak Sealers be used in combination boilers?

Yes, all Fernox internal leak sealers, such as Fernox Leak Sealer F4, are safe for use with combination and other low water content boilers.

They will not block valves or vents. Leak Sealer F4 Express is recommended for all pressurised systems as this can be added in 30 seconds via a radiator, filling loop or Fernox TF1 Filter, without the need to drain the system.

Is it safe to empty central heating water down the drain?

You should only drain central heating system water into the foul water drain or a septic tank.

Never drain system water into road drains or rain water gullies as these go directly into rivers. Never pour water from a central heating system onto the garden or lawn.

How long will Fernox Protector F1 or Filter Fluid+ Protector last?

Normally a treatment will last the life of the system but an annual check to determine whether further dosing is necessary is recommended.

If the system is drained, it will need to be re-treated with a further full dose of Protector. You can check if the system is properly dosed using a Fernox Protector Test Kit.

Can I overdose with Fernox Protector F1 or Filter Fluid+ Protector?

No, overdosing is not detrimental to the system. It is important to ensure that sufficient Protector is present in the system.

There is a test kit and a postal testing service to check the Protector concentration. Refer to Protector Test Kit product data sheet for further guidance.

What can cause knocking noises in boilers?

Boiler noise results from localised boiling of the water. This happens when the inside surface of the boiler becomes too hot due to scale or baked- on sludge deposits.

All systems over five years can suffer noise and new boilers in old systems are especially vulnerable. Add Fernox Boiler Noise Silencer F2 and / or de-scale the boiler with Fernox DS40 System Cleaner and protect with Fernox Protector F1 or Filter Fluid+ Protector.