The 3/8" 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 3/8" 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 3/8" 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 3/8" 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 3/8" 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.