Learn about the advantages and disadvantages of this commonly used mechanism and how it can be affected by issues like leaking non-return valves or their absence. Weekly Boiler Tips are compiled by the knowledgeable and remarkably prolific content creators at WARE, a family owned, third-generation, 69-year-old commercial and industrial boiler rental and service firm based in Louisville KY. You can learn all about this and more at WARE's Boiler University.