This will be useful someday i never knew the pepsi method, will have to try that out if and when my drain gets clogged in the future! Navien tankless water heater combi. Asap installed a new water heater very neat and professional job the technicians had a very pleasant demeanor and were easy to deal with great job asap! Couldn't have asked for more thanks drain masters! Emergency plumbers provides an extensive range of plumbing and boiler services throughout the london area we’ve.