Sentinel Leak Sealer 1L, Seals All Minor leaks and Weeping Joints in Heating Systems, Suitable for All Metals Including Aluminium, Will not Cause blockages in The Heating System

Definitely works and makes the the heating run quieter.

We had a leak in the central heating system so the boiler needed topping up every week. I’m average at DIY but I managed to drain a radiator down a bit and add the leak sealant after watching a YouTube video. I refilled the system and set the central heating going. After another top up a few days later the leak has stopped!!! Brilliant- what a great product. I didn’t expect it to work but thought I’d give it a go before resorting to shelling out on a plumber . Must have saved myself a few hundred quid. Wood recommend this product.

Easy to use, just poured into a radiator using an easifill funnel, pretty thick stuff like pva glue. I added it to an empty old system with a slow pressure drop (less than a bar drop in 6 months) and there has been no pressure drop since. Ensure you air the system fully as it is prone to capturing air.

Easy to use.

After having a pressure drop on our combi for months and no signs of a leak anywhere (suspected a draincock behind an inacessible wall) added this sealer with no great hopes.Within a few days wasn't having to repressurise the boiler quite as much, and after a couple of weeks, no pressure loss at all.Been a good few months now and pressure gauge hasn't moved at all! Worked for me!

Bought this product on recommendation, we've had a pressure drop for a while on the central heating & after 2 unsuccessfull call outs with british gas a friend told me about this. It did the trick, it's been 3 weeks now & the pressure is holding fine

Read many a review and this produce was rated quite high so purchased it, followed the insterlation instruction ran the heating for the required period turned it off and left it for the 24hrs as stated on the instructions. Checked it the following day and the system had not only lost pressure but it was lower than before the treatment. So still trying to find the leak.its possible this solution was just not the right one for my problem but it was recommended by the heating engineer.

Followed instruction and fixed my heating leak first time. Very impressed