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Fernox Central Heating Leak Sealer F4 500ml

Product Code: 45902

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

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Safety Data Sheet (COSHH)


4.8889 5 9

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Fernox Central Heating Leak Sealer F4 500ml 4.9 5 9 9
top quality overpriced but the best for the job and accepted on all my guarantee requirements for certificates 29 Mar 2015
Leak sealer Again screw fix has come up with the goods,can not fault the quality of service and value for money . 17 Jan 2015
Does Exactly What It Is Suppos I have an oldish CH system (about 40 years old) and have been bothered for ages by a variety of hard-to-trace weeps. I recently had a new pressurised boiler fitted and the system was losing pressure at the rate of around 0.1 - 0.2 bar per week (more than 0.5 litres per week).I added the fernox and the system has lost no noticeable pressure over a period of a month. Better than expected result! 23 Jul 2013
Does exactly what it says ! Having had a fairly bad leak from a large vertical radiator (poorly welded joints) I decided to give Fernox F4 a go by adding the whole bottle to my central heating header tank in my loft...and then draining a few pints off from one of my radiators...to get the stuff into the system & circulating. Amaizingly after only 2 hours of running the central heating...the leak had stopped completely !. Fantastic product.- does exactly what it says !. 31 Jan 2013
  • 2015-05-25T14:46:18.616-05:00
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Brand Fernox
Manufacturer Guarantee 10 years
Manufacturer Guarantee 10 years
Model No F4
Pack Size 1
Product Type Central Heating Leak Sealer
Sealant Adhesive Volume 500 ml
Total Product Weight 572 kg