Number reviews: 10
Overal rating: 4
Review for Fernox Leak Sealer F4 500ml by Phil
18th July 2023
I’ve used this many times in a previous life and it’s 50/50 whether it works or not.
Large leaks you’ve got no chance, smaller leaks it might work.
Boiler manufacturers don’t like this stuff as although it states doesn’t block systems if you’ve got a dirty sludgy system it’s going to make things worse as it can cling to the dirt.
If you can’t find the leak and this is your only option it’s best drain the system fully to try and get as much suspended dirt out first.
Review for Fernox Leak Sealer F4 500ml by rodge/handyman
11th January 2023
i had a slow loss of pressure in my system and could not find leak anywhere, had to keep topping the boiler up i then drained a little water out and put fernox in at the bathroom towel radiator then put water pressure back up to just over 1 and run the heating constant for best part of 2hrs leak solved pressure set at just over 1 and staying there !! would highly recommend.
Review for Fernox Leak Sealer F4 500ml by South Yorkshire Heating
13th June 2021
Always like the security that using a reputable product from a company you can trust. Does what it says and in a good safe way. They have the back up of fantastic product knowledge over a long time so you can have great confidence.
Review for Fernox Leak Sealer F4 500ml by DAJ
8th June 2021
Used once on a micro bore system that had a fair few minor leaks that were untraceable.
Couldn’t tell you if it worked or not but we didn’t get back to the job.
Went in well and assume it did what it says. Big house to re-pipe.
Review for Fernox Leak Sealer F4 500ml by Verisafe (Derby) Ltd
19th March 2020
I have used this product on various jobs and have always been pleasantly surprised by the results. A quality product that give piece of mind.
Review for Fernox Leak Sealer F4 500ml by ADOGAS
13th July 2019
Have used this product since I started in the industry and it works really well. Only hardens when comes into contact with air. You can also use it with other sentinel products and doesn’t cause any issues. I usually put it into the bathroom rad if there’s available. Otherwise drain down the header tank to ensure it gets into the system and does the job. Or in the magnetic filter if there is one.
Review for Fernox Leak Sealer F4 500ml by Heat Trend
2nd April 2019
have used a couple of times where I can't get to all the pipe work. does seem to work although got called back to one leaking a year after using this. be careful as not all boiler manufacturers allow it. should only be last resort
Review for Fernox Leak Sealer F4 500ml by McGrath Heating Services Ltd
25th March 2019
Used this product quite a few times now where there is a small leak on system and am unable to find worked well on the ones I added it to no callbacks and not a big expense to customer
Review for Fernox Leak Sealer F4 500ml by Ultimate Plumbing and Heating Services
30th November 2018
I have used Fernox leak sealer for years now and have found it to be very good.I have tried other brands but I always return back to this product.I would recommend this if you cannot find the leak .
Review for Fernox Leak Sealer F4 500ml by Cliff Plumbing & Heating Limited
30th September 2018
Best leaker sealer I have used and well worth the money. 80% of the time when a customer reports losing a small amount pressure in heating system, one dose of this cures the leak. Will continue to only use fernox for leak sealer
No questions
