Guidelines for Vacuum Breaker Installation, Operation and Maintenance
Troubleshooting The most common problem associated with atmospheric vacuum breakers is the occurrence of spillage of water from underneath the vacuum breaker cover. There are many possible causes of this. Set forth below is a list of the potential causes of spillage, together with the appropriate solution for the problem: 1. Vacuum Breaker Installed At Angle. As noted above, if a vacuum breaker is installed in a tilted or angled position, the float cup will not seal evenly against the bottom of the bonnet. To address this issue, adjust the position of the vacuum breaker so as to be plumb and level. 2. Contamination of Float Cup Gasket. If the water contains a high level of calcium or other minerals, deposits and scale can accumulate on the float cup gasket. If this occurs, the gasket will not seal completely against the bonnet. The gasket should be cleaned or replaced. 3. Contamination of Bonnet. Build-up of deposits can occur on the seating surface of the bonnet as well. The bonnet must then be cleaned or replaced. 4. High Water Pressure. As noted above, WaterSaver vacuum breakers are designed specifically for laboratory applications. The float cup and gasket are extremely light to permit sealing at as low a flow as possible (since many laboratory procedures require low flow over an extended period of time). When used in water systems with high water pressure (greater than 70 PSI), these components can wear out more quickly than at low pressure. If that occurs, the vacuum breaker may not seal properly at low flow. In higher pressure applications, the float cup and gasket might require replacement at more frequent intervals. 5. Deterioration of Bonnet Gasket. The vacuum breaker bonnet is sealed into the vacuum breaker body using a nylon gasket or O-ring. Over time, this gasket or O-ring can deteriorate and leakage can occur. In that event, the gasket or O-ring should be replaced.
6. Connection to Elevated Equipment. As noted above, the vacuum breaker must be installed at least 6” above the flood level rim of the sink or the highest point which can be reached by a hose attached to the outlet. Thus, if a hose is attached to the serrated end of a laboratory faucet, the free end of the hose should not be capable of reaching a height that is less than 6” below the vacuum breaker. Spillage can occur in the event that a hose is attached to a faucet and extended above the level of the vacuum breaker. In this situation, when the valve is opened and water is flowing through the system, there can be an accumulation of water in the hose downstream of the vacuum breaker. The pressure created by the weight of the downstream water may exceed the water pressure upstream of the vacuum breaker, causing a negative pressure situation. This will cause a reversal of flow, the vacuum breaker will close, and spillage will occur. In this situation, the vacuum breaker is acting exactly as it is designed in preventing backflow. The situation described above is most likely to occur when the water control valve is opened a slight amount and left in this position for a long period of time. Fluctuations in supply line pressure and flow may cause the float cup to “flutter” rather than seal continuously against the bonnet. This will accentuate the tendency for a negative pressure situation to develop. One possible solution for spillage of this type is to install a non-positive closing volume control device (such as the WaterSaver BO358 ) on the faucet outlet. The control valve can then be fully opened, permitting the vacuum breaker float cup to seal. Water flow is metered using the volume control on the outlet. As noted above, the Uniform Plumbing Code requires that vacuum breakers be located on the discharge side of the last valve in the water line. Therefore, the volume control device must not be capable of fully closing.
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WaterSaver Faucet 701 W Erie St Chicago, IL 60654
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