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 Guarantee
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Safety Data Sheet
Additional Information
Technical Specification
  • Brand : Sentinel
  • Product Type : Internal Leak Sealer
  • Volume : 1 Ltr
  • Pack Size : 1
  • Manufacturer Guarantee : 1 Year 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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€17.95 Incl. 20% VAT

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Sentinel Internal Leak Sealer 1Ltr is rated 4.6 out of 5 by 7.
Rated 4 out of 5 by from Sealed some invisible leaks Added this to a customer's sealed heating system which kept losing pressure but no visible leaks, now it's fine.
Date published: 2013-06-15
Rated 5 out of 5 by from Great product Used to solve a leaking compression T which was in a difficult to get at location and would have required a drain down and new inhibiter. The leak was generating approx. 1 pint every 3-4 hours to give you an idea. The liquid is very thick, I drained a few of pints from a rad in a tiled area and removed the whole bleed valve and used a 6inch cut of garden hose with a funnel to get it directly into the system. Took a good 5 mins to get it all in. Let the heating run on a boost and by 30mins the leak had virtually dried up and after 1 hour was good to go. Saved hours of work and wasn't looking forward to recharging the whole system, and bleeding it out. They didn't have the Fernox product in stock at my branch but am very pleased with the performance of this
Date published: 2013-05-28
Rated 5 out of 5 by from Great leak sealer bought this to seal a small leak that i had on an inexcessable pipe and it did the job
Date published: 2013-05-04
Rated 5 out of 5 by from Leak Sealer without hustle excellent product to repair small leak under tailed floor without removing anything. Quick and easy.
Date published: 2012-03-04
Rated 5 out of 5 by from bala every 2 days my boiler pressure went down to 0. after i put sentinel in the system pressure remain same. best one
Date published: 2011-03-29
Rated 5 out of 5 by from Very good purchase This product is very good if you have an underfloor leak you cannot find. Great problem solver. Works on sealed system as well as open vented. The chemical doesn't damage any T.R.V 's.
Date published: 2008-12-09
Rated 3 out of 5 by from Try the no nonsense Got this leak sealer , but compared to the No Nonsense it is very watery didn't perform as well as expected Wouldn't buy again
Date published: 2008-10-01
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