Main water valves come in a variety of styles, types, and sizes. Valves will vary depending on the size and type of the property, and if fire protection is involved. The main control valve is the valve that is at then end of the water service line inside the building. If the main valve fails there is no way to other valve inside the building that will allow you to work on that particular valve to repair it. That is when a main water valve replacement is needed. That is why it is best to use a valve that is closest to the inside plumbing of the building, not the valve closest to the street, when you need to shut the water to a building.
When a main control valve breaks and a main water valve replacement is needed it requires expertise and know-how to do the job safely and to code. Working on a live main is no simple task and it poses some risk of property damage if done improperly, or by an inexperienced or unlicensed individual.
What if a valve breaks in the closed position?
In most cases if a gate valves breaks in the closed position extensive work has to be done. Sometimes a curb valve will be located in the sidewalk area which would enable you to close the curb valve using the proper tool. You could then remove the broken valve with little trouble. If there is very little room to work inside the basement where the valve is located and there is no curb valve, the roadway may have to be opened in order to close the tap connection itself. Opening the roadway can be fairly costly and will involve securing DOT permits.
Changing out a main control valve under pressure can be a very tricky proposition and sometimes dangerous. Removing a valve under water pressure can sometimes be done by highly skilled plumbers, but never when live electric services are nearby. One should never risk an injury just to save a few dollars. Read more about changing a water valve.
The different types of valves
A gate valve, as the name implies, has a gate built into the body that is raised or lowered by turning the valve handle. The correct way to open a gate valve is to turn the handle counter-clockwise without applying any excessive force or using a jerking motion. A 1″ water valve will take about six full turns to fully open. You should stop turning the handle as soon as there is any resistance.
Turning the handle or stem too far with excessive pressure can cause damage and very often will cause a leak. In some cases the stem can snap, making the valve gate frozen in place. never risk breaking a main control valve in the closed position. If resistance is met, always gently work a valve back and forth. This will free up any corrosion or sediment.
A ball type valve has a bored out ball inside the valve body. A ball type valve only requires a quarter of a turn of the handle to fully open or close. There is an arrow on the handle to indicate which direction to turn the handle to either open or close it. When opening or closing a ball valve do so slowly or abrupt rushes of water going through the plumbing system can cause damage and leaks. This type of damage is called water hammer.
Always have a faucet on a top floor of the building open to monitor water flow and let air escape when water is being introduced back into the plumbing system. That rule of thumb applies for reopening any type of water valve.
Technically OS&Y stands for ‘outside screw and yoke’. Which means that when the handle is turned it directly raises and lowers the gate of the valve by interacting directly with the stem of the valve. The handle and the stem are both threaded so they interact together (this is different than a typical gate valve). The stem of the valve itself raises and lowers visibly outside the body of the valve, while the handle remains in a fixed position. As the stem rises the gate inside the body of the valve rises in unison letting water flow through the body of the valve.
OS&Y valves are required for fire service lines in NYC because it is always clear whether the valve is open or closed. The fact that the valve stem visibly rises and lowers is vitally important because dedicated fire mains are not connected to plumbing fixtures. Therefore they cannot be easily tested to determine if the water is on or off.
Who to hire to perform a main water valve replacement
In New York City only Licensed Master Plumbers are permitted to perform a main water valve replacement. It cannot be emphasized strongly enough that hiring an unlicensed, uninsured, or unskilled individual to work on a live water main can have disastrous consequences. If improper work is done resulting in damage an unlicensed and untrained person will probably also have no insurance to cover the cost of the damage – which could be substantial.
Hiring a licensed, insured, and experienced plumbing firm is an assurance of a job well done. A plumber being experienced in all the different types of valves, no matter the size, allows a relatively simple plumbing repair to remain that way.
Joseph L. Balkan Inc. is a licensed plumbing company in business for over 60 years with a high degree of expertise in handling any sewer line repair or water main situation. Balkan provides free on-site visits seven days a week, and expert advice is a call or mouse click way.