A boiler is a closed vessel in which water or other fluid is heated.The fluid does not necessarily boil.
(In North America the term "furnace" is normally used if the purpose is not actually to boil the fluid.) The heated or vaporized fluid exits the boiler for use in various processes or heating applications,12 including water heating, central heating, boiler-based power generation, cooking, and sanitation.Źródło: https://en.wikipedia.org/wiki/Boiler
Years of training and/or experience are needed to become a skilled plumber; some jurisdictions also require that plumbers be licensed. Some needed skills, interests, and values Reading drawings, and specifications to determine layout of water supply, waste, and venting systems Detecting faults in plumbing appliances and systems, and correctly diagnosing their causes Installing, repairing and maintaining domestic, commercial, and industrial plumbing fixtures and systems Locating and marking positions for pipe connections, passage holes, and fixtures in walls and floors Measuring, cutting, bending, and threading pipes using hand and power tools or machines Joining pipes and fittings together using soldering techniques, compression fittings, threaded fittings, and push-on fittings. Testing pipes for leaks using air and water pressure gauges Awareness of legal regulations and safety issues Ensuring safety standards and build regulations are met. United States Each state and locality may have its own licensing and taxing schemes for plumbers. There is no federal law establishing licenses for plumbers. United Kingdom Plumbers in the United Kingdom are required to pass Level 2 and Level 3 vocational requirements of the City and Guilds of London Institute. Źródło: https://en.wikipedia.org/wiki/Plumber#Plumbing_activities
Plumbing is any system that conveys fluids for a wide range of applications. Heating and cooling, waste removal, and potable water delivery are among the most common uses for plumbing however plumbing's not limited to these applications.1 Plumbing utilizes pipes, valves, plumbing fixtures, tanks, and other apparatuses to convey fluids.2 Trades that work with plumbing such as boilermakers, plumbers, and pipefitters are referred to the plumbing trade. In the Developed world plumbing infrastructure is critical for public health and sanitation.34 The word derives from the Latin plumbum for lead, as the first effective pipes used in Roman era were lead pipes.Źródło: https://en.wikipedia.org/wiki/Plumbing.