Relief Valves – RL4 Series

Parker RL4 Relief Valves are designed such that when the upstream pressure exceeds the closing force exerted by the spring, the lower stem opens, permitting flow through the valve. Flow hrough the valve increases proportionately to the increase in upstream pressure.

Dimensions in inches (millimeters) are for reference only, subject to change.
The correct part number is easily derived from the following example and ordering chart. The eight product characteristics required are coded as shown in the chart.
Example 1 below describes an RL4A Series externally adjustable relief valve equipped with ¼” CPI™ compression inlet and outlet ports, Nitrile seals, PTFE back-up ring, stainless steel construction, and a 100 to 150 psig (6.9 to 10.3 bar) spring kit.
Example 2 below describes an RL4A Series externally adjustable relief valve equipped with 1/4″ male NPT inlet port , ¼” female NPT outlet port, ethylene propylene seals, PTFE back-up ring, stainless steel construction, manual override option, and a 10 to 225 psig (0.7 to 15.5 bar) spring kit.
Example 1: 4Z-RL4A-BNT-SS-KD (shown in the part number blocks below)
Example 2: 4M4F-RL4A-EPRT-SS-MN-KF