Provides long term protection against corrosion and limescale formation in domestic central heating systems.


Inhibitor which prevents corrosion and limescale formation in central heating systems. Includes enhanced pH buffering to ensure the system water pH level does not drop below 6.5 or above 8.5 - the optimum pH range for preventing corrosion and limescale build-up. In line with BS 7953:2019 regulations and best practice, and for long-term protection of the system, concentration levels should be maintained and checked annually as part of the boiler or system service. Compatible with all other Fernox products and is suitable for use with all materials and metals used in central heating systems, including aluminium.


• Protects against corrosion and scale in mixed metal central heating systems
• Stops frequent venting of radiators
• One 500ml recyclable bottle treats up to 130 litres of system water (16 radiators) and the equivalent of 250m2 of underfloor systems.

Delivery (UK mainland only)

 

Next Day: £5, or FREE over £40

- Order by 9pm Mon-Thu: next working day

- Order Fri to 5pm Sun: Monday

- Order after 5pm Sun: Tuesday

 

Pre-12pm: £10

- Same cut-offs as Next Day above

 

Saturday & Sunday: £10, or £5 over £40, or FREE over £75

- Saturday: order by 6pm Fri

- Sunday: order by 4pm Sat

 

Heavy items (over 30kg)

- Mon-Fri only. Order by 6pm and allow up to two working days

- Order after 6pm Thu: arrives after the weekend

 

Supplier items

- Sent directly by the supplier, so timings vary. Lead times appear on the product page in working days (Mon-Fri)

 

More about delivery 

Next Business Day Collection (eligible items)

- Order by 9pm Mon-Thu: collect next day

- Order after 9pm Thu to 5pm Sun: collect Monday

- Heavy items (over 30kg): allow up to two working days

 

Opening hours

- Weekdays vary by branch: open 6:30am-7am, close 6pm-8pm

- Saturday: 7am-6pm

- Sunday: 9am-4pm

 

Check your local store's hours and that it's open before visiting. Please wait for our text or email before collecting.

 

Holding your order
We'll hold it for 14 days, then automatically refund your original payment method.