Which supermarket is cheapest? Using an effective chemical inhibitor can decrease the corrosion rate and prevent the build-up of sludge and scale, thus preventing deterioration and helping to maintain efficiency. Request an appointment for service today! We’d advise switching off the boiler, and calling an emergency plumber to rectify the problem. If a blocked drain is making your life a misery, call our team at a better service today and let us clear up the problem on your behalf. Clean.