Pressure relief valves prevent system overpressurization. The following table states the valve cracking pressure at which the valve relieves and the suggested working pressure range for each valve.

WARNING!

To reduce the risk of serious injury, including fluid injection, splashing in the eyes or on the skin, injury from moving parts, or fire and explosion, be sure to follow these precautions:

• Always relieve air and fluid pressure in the system before servicing the valve.
• Be sure that the fluid working pressure of your system is within the suggested working pressure range of the relief valve. Fluid leakage, nuisance cracking, or system component rupture may occur if the system working pressure does not fall within the suggested working pressure range.
• Do not modify, remove, or plug the pressure relief valve.
• Keep the valve in good operating condition. Clean the valve daily when using filled materials. Filled materials may obstruct the internal moving parts of the valve.
• Do not remove the Warning Label. It contains important warnings and instructions. Additional Warning Labels can be ordered at no charge from Graco.
• Ground the entire system, including the pressure relief valve, when pumping flammable liquids.