It works i used product in bathtub where water was running out slow water is flowing freely again! This data is sourced from the training providers for more detailed information, contact the training provider for the course you’re interested in. Didn't unblock sink at all,if anything is was more blocked after applications, even when left for hours! Finding and stopping leaks is a plumber’s specialty, so if you notice one, give your plumber a call. Whether your boiler is in or out of warranty,.