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Product Frequently Asked Questions:
Domestic Water Piping Specialties


A vacuum breaker is a device designed solely to protect against backsiphonage on a plumbing system. Vacuum breakers can not prevent against backpressure, and are generally not testable devices. A backflow preventer is a device designed to prevent both backsiphonage and backpressure. 

Examples of vacuum breakers include pipe applied atmospheric type vacuum breakers [Model 35XL], hose-connection vacuum breakers [Model BFP-9] [Model BFP-8F], pressure vacuum breakers [Model 720A] [Model 420XL], laboratory-faucet vacuum breakers [Model 35XLVCH] [Model 730], and spill-resistant vacuum breakers [Model 460]​

Dual checks are not testable in line whereas double check and reduced pressure principle devices are. dual checks and double checks prevent against low hazard threats (water discoloration, smell and taste), whereas reduced pressure principle devices protect against these as well as high hazard threats (dissolved chemicals in the water that can cause illness and/or death).

Examples of dual check backflow preventers are [Model 700XL] [Model 705] [Model 700FP]. Examples of dual check backflow preventers designed specifically for beverage dispensing equipment are [Model 700XL] [Model 705].

Examples of dual check backflow preventers are [Model 350A] [Model 350AST] [Model 350XL 450] [Model 950XLT2] [Model 350]

Examples of reduced pressure principle backflow preventers are [Model 375A] [Model 375XL] [Model 375ST] [Model 375AST] [Model 375]
What is a detector assembly on a double check or reduced pressure principle device?
Plumbing systems that are by code not connected to a water meter (such as fire hydrants) have no way of determining whether water is being consumed downstream of the device via either component malfunction or water theft. A detector assembly is a bypass system with its own inline meter, designed to detect low flow rates through a normally un-metered plumbing line that requires a backflow device. 

Examples of double check detector assembly backflow preventers are [Model 350ADA] [Model 350ASTDA] [Model 950XLTDABF] [Model 350DA] [Model 450DA]

Examples of reduced pressure detector, fire-protection, backflow-preventer assemblies are [Model 375ADA] [Model 375ASTDA] [Model 475DA] [Model 375DA]
A water regulator is a direct acting device. This means that the entire flow through the plumbing system is directed through the valve itself. A regulator contains a spring that biases the valve open, based on a set pressure range. Once the downstream pressure in the plumbing system is exceeded the spring compresses and the valve inside the regulator begins to close. A water control valve is a diaphragm valve with a pilot assembly that is plumbed outside of the main body of the valve. The actions of this pilot assembly control the operation of the main valve. In the case of a pressure regulating water control valve, the pilot assembly would contain a water regulator thereby regulating water pressure in the main valve.  water regulators tend to be for pipe sizes from ½” to 3”, whereas water control valves tend to be in pipe sizes from 1¼” through 10” and larger as required. 

Examples of water regulators are [Model NR3XL] [Model 500XLTYSBR] [Model 600XL] [Model 70XL].

Examples of water-control valves are [Model ZW209] [Model ZW206] [Model ZW205].
A temperature actuated water mixing valve combines both hot and cold water. Inside the valve is a piston type actuator that is sensitive to a very precise temperature range. This element opens and closes the hot water supply such that the resulting water mix falls within a given temperature range. Temperature actuated water mixing valves are designed to be used either at the source (water heater) or at the point of use. Water temperature limiting devices and primary thermostatic water mixing valves are categories that are intended to be used at the source and comply with ASSE 1017. Individual fixture, water tempering valves are point of use and comply with ASSE 1070.

Examples of water regulators water temperature limiting devices and primary, thermostatic, water mixing valves are [Model 1017XL] [Model ZW1017XLHT].

Examples of individual fixture, water tempering valves are [Model ZW3870XLT] [Model ZW3870XLT-4P] [Model ZW1070XL].

A compression style hydrant (Zurn Z1310) operates by turning the handle which moves the operating rod activating a spring-operated plunger with a rubber compression seat.   A ceramic disc style hydrant (Zurn Z1321) features a 1/2 turn cartridge which allows water to pass through an opening within the rotated cartridge.  These hydrants are designed to provide a longer lifespan than a traditional compression fitting.

A trap primer is a plumbing device designed to divert a small amount of water away from another plumbing fixture and feed traps in other fixtures such as floor drains.  Electronic trap primers (Zurn Z1020) is a standalone unit that operates automatically at programmed intervals to dispense a measured amount of water to 5 to 40 separate lines.  Another type of trap primer takes the place of a traditional lavatory P-trap (Zurn Z1021).  Zurn offers an a trap primer outlet adapter as well (Z1023)​