Different types of valves
Valves vary widely in form and application. Sizes typically range from 0.1 mm to 60 cm. Special valves can have a diameter exceeding 5 meters.
Valve costs range from simple inexpensive disposable valves to specialized valves which cost thousands of US dollars per inch of the diameter of the valve.
Disposable valves may be found in common household items including mini-pump dispensers and aerosol cans.
A common use of the term valve refers to the poppet valves found in the vast majority of modern internal combustion engines such as those in most fossil fuel powered vehicles which are used to control the intake of the fuel-air mixture and allow exhaust gas venting.
Źródło: https://en.wikipedia.org/wiki/Valve
List of plumbing subsystems
The major categories of plumbing systems or subsystems are:
potable cold and hot tap water supply
plumbing drainage venting
sewage systems and septic systems with or without hot water heat recycling and graywater recovery and treatment systems
Rainwater, surface, and subsurface water drainage
fuel gas piping
hydronics, i.e. heating and cooling systems utilizing water to transport thermal energy, as in district heating systems, like for example the New York City steam system.
Źródło: https://en.wikipedia.org/wiki/Plumbing
Professional plumbing
The hydraulic system is a very important part of any building, so it's good to care for her. If you are a failure, you should immediately call the appropriate service hydraulic, and at the same time it is necessary to remember that he was a proven and reliable. Only those reputable, recommended by many companies are able to provide us with services of the highest quality, which is why it is good to try when selecting specific professionals. Ideally, it was the service, which have used our friends or that is recommended on internet forums. Only such a professional company will be good, if we want our hydraulic system worked flawlessly.