The 1/2" Wilkins Model 420 pressure vacuum breaker began production in 1998 and was discontinued in 2013. The 420 was replaced with the 420XL, which is the lead free version. The 420 was designed as a freeze resistant vacuum breaker. The 420 still must be winterized as it is "freeze resistant" not "freeze-proof." The check assembly is self contained and has a replacable seat. The air inlet uses a rubber fold instead of the traditional spring inlet. In 2010, a lead free version was created. Leaded and lead free versions use the same internal parts.No special tools are required for servicing.
The 1/2" Wilkins Model 420XL pressure vacuum breaker began production in 2010 and is still currently being produced. The 420XL is a lead free device and replaced the old model 420 which was not lead free. Leaded and lead free versions use the same internal parts. The 420XL was designed as a freeze resistant vacuum breaker. The 420XL still must be winterized as it is "freeze resistant" not "freeze-proof." The check assembly is self contained and has a replacable seat. The air inlet uses a rubber fold instead of the traditional spring inlet.No special tools are required for servicing.
The 1/2" Wilkins Model 420 pressure vacuum breaker began production in 2007 and was discontinued in 2013. The 460 was replaced with the 460XL, which is the lead free version. The 460 was designed as a spill resistant vacuum breaker. The check assembly is self contained and has a replacable seat. Leaded and lead free versions use the same internal parts. The bonnet has a built in tool to disassemble the check assembly.
The 1/2" Wilkins Model 420XL pressure vacuum breaker began production in 2010 and is still currently produced. The 460XL is a lead free backflow preventer. The 460XL replaced with the 460, which is the non lead free version. The 460XL was designed as a spill resistant vacuum breaker. The check assembly is self contained and has a replacable seat. Leaded and lead free versions use the same internal parts. The bonnet has a built in tool to disassemble the check assembly.
The 1/2" Wilkins model 720 & 720A pressure vacuum breaker began production in 1975 under the SMR name. It was sold to Neptune Meter Company in 1978. Wilkins bought the rights to the device in 1984. It is a bronze bodied, fully testable device. The "A" suffix is for the reworked air inlet design. Both models will accept the modified air inlet parts. In 2010, the test cocks were moved from the body to the ball valves. No special tools are required for servicing.
The 1/2" Wilkins 975 Reduced Pressure Zone backflow preventer was introduced in 1990 and was discontinued in 1992. The 975 was replaced by the 975XL which featured removable seats, while the original 975 did not have removable seats. All other parts will interchange between the 975 and 975XL models. The checks are a poppet style and are not self contained and there is spring pressure against the covers. The relief valve is a piston style with an internal sensing line. This device does not meet low lead laws introduced in 2014. A lead free version is available, known as the 975XL2. No special tools are required for servicing.
The 1/2" Wilkins 975XL Reduced Pressure Zone backflow preventer was introduced in 1993 to replace the earlier model 975. The 975XL features removable seats, while the original 975 did not have removable seats. All other parts will interchange between the 975 and 975XL models. The checks are a poppet style and are not self contained and there is spring pressure against the covers. The relief valve is a piston style with an internal sensing line. This device does not meet low lead laws introduced in 2014. A lead free version is available, known as the 975XL2. A seat removal tool is required for seat service.
The 1/2" Wilkins 975XL2 Reduced Pressure Zone backflow preventer was introduced in 2010 as a lead free alternative to the model 975XL. The 975XL2 features a three cover design, with removable seats. All parts will interchange between the 975XL and 975XL2 models. The checks are a poppet style and are not self contained and there is spring pressure against the covers. The relief valve is a piston style with an internal sensing line. This device meets low lead laws introduced in 2014. A seat removal tool is required for seat service.