Sentinel Internal Leak Sealer 1Ltr

Product Code: 99730
Sentinel Internal Leak Sealer 1Ltr
Product Code: 99730
Internal Leak Sealer for small inaccessible leaks and weeping joints in all types of indirect heating systems including those containing aluminium components. Compatible with elastomers.


  • 1 Year Manufacturer's Guarantee
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Safety Data Sheet
€17.45 Incl. 20% VAT
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Additional Information
Technical Specification
  • Brand : Sentinel
  • Sealant Adhesive Volume : 1 Ltr
  • Product Type : Internal Leak Sealer
  • Pack Size : 1
  • Manufacturer Guarantee : 1 Year Manufacturer's Guarantee
  • Pieces in Pack/Case : 1
Product Contents
Delivery & Returns


Standard delivery: €15

Free delivery on all orders over €70.00

Click here to see information on our delivery charges and times



Hopefully you won't need to return an item, however, if you do, it is our aim to make this as simple as possible. By following the guidance below you can help us to help you when a product is not what you expected, or is faulty. Your statutory rights are not affected by this guidance.


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Sentinel Internal Leak Sealer 1Ltr is rated 4.8 out of 5 by 34.
Rated 5 out of 5 by from Well worth trying My 15 year old Worcester 24i combination boiler was losing pressure daily resulting in the overheat sensor tripping out. Told by heating engineer that must have a leak in system as nothing wrong with boiler. Assumed not in upstairs pipework or radiators as no sign of water damage. Did not fancy having to lift carpets and flooring down stairs to try and find leak. Bought Sentinel leak sealer to give it ago although a little sceptical it would work. BUT IT DID WORK. Boiler pressure now stable for last ten days. Only thing to be aware of is that it does not flow easily as is like thick PVA glue. So make sure if using tubing and funnel that it is large enough to flow easily. I drained system down enough to take off valve from upstairs radiator and fed tube into pipe. Worked for me. Better than lifting all the downstairs flooring! Happy days.
Date published: 2016-11-21
Rated 5 out of 5 by from Well worth the money I purchased this to sort out a small leak I had on my towel radiator, I removed the non bleed valve plug and used a length of tubing to remove a ltr of water, I then poured in Sentinel leak sealer, replaced the plug, turned on the system bled the radiator, hey presto no more leak. I would highly recommend this product to anyone who has the same problem.
Date published: 2016-11-08
Rated 5 out of 5 by from Sentinel Leak Sealer I have used this product for over 12 years. The condition of Systems is always clean and corrosion free. The price at Screwfix is excellent.
Date published: 2016-09-24
Rated 5 out of 5 by from Great Very good product I really recommend it, work on the first time really great good nice brilliant smells nice !!!!!!!!!!!
Date published: 2016-04-18
Rated 5 out of 5 by from Sealed the leak Using this marked the end of a 2 month search for a leak that couldn't be found. The noise coming from the central heating pump has changed noticeably since adding this but I cannot comment on whether this is a good or bad thing... something to keep monitoring I think.
Date published: 2016-04-05
Rated 5 out of 5 by from Brilliant Had a mystery leak somewhere under floor that could not be detected, leading to regular pressure drops and topping up of system on a daily basis. I thought I'd give this product a try before ripping the entire flooring up and hey presto it worked! I poured it into the system through the top of the bathroom towel rail as this was easy access, turned on the boiler for a short while as per the instructions and that was it. Several months later still no problems and pressure is constant. One of the best products I've used, highly recommended.
Date published: 2016-02-29
Rated 5 out of 5 by from Easy to use and works! Had a small leak somewhere inaccessable, so drained the system a bit, poured into top of bathroom towel rail (highest point), refilled and bingo. No leak.
Date published: 2016-01-23
Rated 5 out of 5 by from Finally. Job done. After a very long time suffering the inconvenience of the boiler not coming on in the morning because of the loss of pressure overnight we are finally waking up to a warm house. Adding the sealant could not have been easier. I used a towel radiator upstairs as this is the highest point and filling through the top vent is straightforward. Vent any remaining pressure from the system, drain off a litre(ish), remove the vent plug from the radiator, empty contents into system, refit plug, pressurise system and let the sealant do the work. Hey presto! No loss of pressure to date. For this price and the short time to do the job it can only be 5 star and it only needs 2 words. It works.
Date published: 2016-01-21
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