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Fernox F4 Central Heating Leak Sealer 500ml (45902)

Used throughout domestic heating systems for sealing small, inaccessible leaks. Does not block air vents and pumps.

  • 1 Year Guarantee

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£16.99INC VAT (£33.98/Ltr)

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Fernox F4 Central Heating Leak Sealer 500ml is rated 4.4 out of 5 by 20.
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Rated 1 out of 5 by from Boiler Presure Droping Had a leak in heating system thought this would be ideal way to fix it, 5 radiator 1 t/rail 24hrs later, still leaking USELESS STUFF and its not the cheapest Did not work on the last leak either
Date published: 2016-11-20
Rated 5 out of 5 by from saved from a mighty mess. Having developed a leak on some underground skimmer swimming pool pipework and not keen on digging up tiles/floor/ground for 50 metres to find it decided to give this a try.blocked the pipe return at the pool and dumped it into the other end,filled with water and crossed fingers,where was losing 80mm a day in height,now dropped that to under 10...happy days only 4 stars for reliability as its only been 2 weeks but heres hoping
Date published: 2016-11-19
Rated 5 out of 5 by from Miracle Cure Had a tiny leak on a 10mm Microbore joint to a Towel Rad in the Downstairs toilet,losing @ half a cup per day. Didn't really want to be draining full system down etc at this time of year. Read reviews on this product which @95% seemed positive. I have 22 Rads so needed 2 Bottles which did seem dear but worth a try. Very easy to use, drained @ 2 litres from Kitchen Rad via drain off , and then poured contents of both bottles into Bathroom Towel Rad. Because its quite thick didn't need funnel, poured straight in.. Cautiously switched Heating on for 15 mins & worked immediately. I keep checking everyday , been a week now and still bone dry. Don't know how it works but it does , well worth giving it a try.
Date published: 2016-11-18
Rated 4 out of 5 by from Good as always but............ This is the second time I have used this product. 1st two years ago and worked perfectly. The problem of loosing pressure from my combi boiler has now reappeared now winter is here. I have used two 500ml this time and so far so good and await to see if it works long term. if you have a leak that's big the inevitable will be a full repair, F4 can not work wonders!
Date published: 2016-11-10
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Can I use to much I've got 6 twin rads and 3 single rads do i need 1or 2 bottles

Asked by: Dikk
Hi Dikk, you need 2 bottles to treat your system
Answered by: Fernox Client Services
Date published: 2017-03-03

is Fernox F4 suitable for a use with a boiler using a stainless steel microbore heat exchanger / coil

Asked by: jaminb
Hello Jamind. The F4 Central Leak Sealer will be completely fine to use in your system.
Answered by: Fernox Client Services
Date published: 2017-01-29

Does this product work with Plastic pipes e.g. PE-X (speedfit, flo-plast)

Asked by: Harvk
Hello Harvk. The F4 Central Heating Leak Sealer can be used with plastic pipes. Hope this helps.
Answered by: Fernox Client Services
Date published: 2017-01-22

Can Fernox F4 be used in a central heating system that is partly underfloor heating and partly conventional radiators

Asked by: Copycat
Hello Copycat. The F4 can be used on underfloor heating systems, however there can't be any antifreeze in the system, and the underfloor pipework cannot be lagged or covered in concrete for this product to work. Hope this helps.
Answered by: Fernox Client Services
Date published: 2017-01-08

Losing about 1 bar of pressure in about 4 hours, any chance this product could cure it.

Asked by: Landlord3579
Hello Landlord3579. The F4 Central Heating Leak Sealer is designed to stop small weeps and leaks, and from the amount of pressure loss you've described the should be within the products capabilities. Hope this helps.
Answered by: Fernox Client Services
Date published: 2017-02-21
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Specification
Brand Fernox
Manufacturer Guarantee 1 Year Guarantee
Model No F4
Pack Size 1
Pieces in Pack/Case 1
Product Type Central Heating Leak Sealer
Sealant Adhesive Volume 500 ml

Downloads

Safety Data Sheet (COSHH)