Swagelok 177-13K-R4-A Relief Valve Spring Kit

Swagelok 177-13K-R4-A Blue Spring Kit is a color-coded replacement spring assembly for Swagelok's R4-series proportional relief valves, designed to enable precise control of the valve’s cracking pressure without replacing the entire valve body. The kit uses a blue spring designated for the 50 to 350 psig (3.4 to 24.1 bar) range, and Swagelok lists the initial cap position at 12.5 turns to guide correct installation and subsequent tuning for accurate relief performance. This part is identified by the ordering number 177-13K-R4-A and carries the Blue color code; it is intended specifically for R4-series relief valves used in gas or liquid service where proportional relief behavior is required. The Swagelok R4 spring kits are part of the standard maintenance options for these valves, with additional kits in other color codes for higher cracking pressures, providing a straightforward path to adjust set pressure within the R4 family.