This is my first yelp review ever glad i read steve k's review and called jim. Sign up to which? legal for clear, step-by-step advice on problems big and small. Energy classification (heating). Just call drain doctor plumbing and drainage and your drain will be cleared as quick as a wink. You also can consult these technology providers. In other words, the model ‘number’ is not always an indication of heating output, although it occasionally.