Fernox F1 Central Heating Protector 500ml Product Code: 77218

Provides long term protection of domestic central heating systems against internal corrosion, limescale formation and bacterial contamination. Prevents corrosion of all metals. Use on all types of boilers, radiators and pipework systems. Non-toxic.


  • 1 Year Guarantee
  • Stops Frequent Venting of Radiators
  • Prevents Bacterial Contamination


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Safety Data Sheet
Additional Information
Technical Specification
  • Brand : Fernox
  • Sealant Adhesive Volume : 500 ml
  • Product Type : Central Heating Protector
  • Volume : 500 ml
  • Model No : F1
  • Pack Size : 1
  • Manufacturer Guarantee : 1 Year Guarantee
  • Pieces in Pack/Case : 1
Product Contents
Delivery & Returns


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€22.45 Incl. 23% VAT

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Fernox F1 Central Heating Protector 500ml is rated 4.8 out of 5 by 53.
Rated 5 out of 5 by from Good insurance I always use this whenever the system is drained down. Provides the best possible protection against rusting and problems with sludge and blocked rads. Screwfix price is also the best.
Date published: 2018-03-01
Rated 5 out of 5 by from Always use Always make sure my central heating has fernox in it. Just needs it like sugar in me brew.
Date published: 2018-01-23
Rated 5 out of 5 by from Well worth the effort with F3 We have had a combination central heating system (inc new pipes) installed new 18 years ago. It has been serviced every year by a huge/ well known heating firm and has had various parts maintenance in that time. However, in over a decade of service from the well known heating firm, I can never recall a boiler service where the heating water was ever drained and replaced or inhibitor added. We also have had a magniclean device installed on the strong advice of the heating firm. Every engineer visit is accompanied with a brow beating and hard sell of products, the latest being a power flush at over £700. The radiators all seemed to work fine with only one top radiator being cooler than the rest. We researched heavily on power flushing and alternatives. An independant heating engineer recommended initially avoiding the power flush and look to use Fernox F3 Cleaner and Fernox F1 protector. Various reputable online heating forums also gave similar guidance. We decided to go down this route. We have 13 Radiators and used 1 litre of Fernox Cleaner. We isolated the boiler electric and gas and drained down the system via a drain point and hose, some signs of discolour and iron oxide. I guessed the magniclean must be working well. We filled the system slowly, bleeding the radiators on the way up and putting 1 litre of cleaner in via the towel radiator top blanking nut. After this we ran the system for a week as per the instructions to clean the system and seemed to notice the radiators did get hot noticeably quicker and the boiler did seem quieter. After a week, we isolated the boiler gas and electric and drained the system down again. The heating water discharged was heavily discoloured after cleaning for a week and a fair bit of iron oxide was present. We removed the top radiator and flushed this through outside with a hose and this released even more black sludge. We left the top radiator off and refilled the system to rinse the cleaner and residue out. While it was full we opened the top thermostat valve and lock valve into a bucket and washed out some more sludge. We then drained out the system and cleaned/ rinsed the magniclean. The top radiator was replaced and the system emptied of the water used to rinse it. By this time, the heating water discharged was a lot cleaner. The process did result in clearing out a whole lot of black slurry. We then refilled the system for the last time, and this time added 1 litre of Fernox F1 Protector at the top towel radiators, bleeding the system as it filled up slowly. Before we started the heating, we balanced the radiators, having watched a few videos on YouTube on how to do this and get optimum flow around the system. Having switched the heating back on, it is running quieter and heating quicker, the balancing has helped with preventing unevenly cooler radiators, and we are pleased. The Fernox products claim a 15% reduction in gas for heating, but I can’t verify this but would say the system does heat quicker and is burning for shorter periods, so it may be true. Overall we feel that the system must be healthier now for this treatment and are pleased so far and would recommend this. If you do go down this route, allow yourself 2 whole days each a week apart. 1 day to add cleaner, 1 day to rinse and add protector. It won’t take you all day, it is time consuming but well worth it. We will definitely repeat this exercise to keep the system clean and protected.
Date published: 2018-01-20
Rated 5 out of 5 by from Best By Far Have used cheaper brands in the past but have come back to Fernox because in my experience it does outperform all these other brands. In this case it is worth paying out the extra money.
Date published: 2018-01-02
Rated 5 out of 5 by from Fernox F1 Best on market Great price Essential for all central heating systems
Date published: 2017-12-29
Rated 5 out of 5 by from Fernox F1 What can you say, it's the defacto treatment, never had a problem with a system treated with this stuff.
Date published: 2017-12-26
Rated 5 out of 5 by from Fernox name, good price Well, it's Fernox inhibitor. A good price in a handy to get to store.
Date published: 2017-12-14
Rated 5 out of 5 by from Simply The Best! This is still quite simply the best! I've used most of the others over 30 years and always come back to Fernox. Most recent success was a newish heating system making lots of crackling & bubbling sounds. Had just been flushed & treated by someone else with another product. I drained it, then refilled, adding Fernox. Absolutely silent! Another success! I've never seen corrosion in a radiator where this has been used from new.
Date published: 2017-11-23
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