RE: CRS-NC-AP0001B Pressure Relief Valve

This bulletin outlines recommended service requirements for the C&R water system pressure relief valve.

After each race weekend or multiple test days the valve cap (1) should be removed and the piston (2) disassembled.  The 0-ring (3) in the piston should be replaced with a new seal MI-2-109V and lubricated with a small amount of Silicone lubricant 3M-08946 both of these products can be obtained from C&R.

Lubricate the O-ring MI-2-115 (4) and reassemble the PRV.  This O-ring along with the spring (5) and the O-ring MI-2-119 (7) should be replaced after every fifth rebuild.  When replacing the spring the valve cracking pressure should be checked and the new spring shimmed to obtain the desired level.  Shims can be placed between the spring and the cap in position marked (6) below.  Each 0.015” thick shim MCM90135A451is worth between 1 & 2 PSI depending on the spring used.  Ensure the screen  1018200105A (8) is clean and not damaged and replace as necessary.

See drawing NC-AP0001B for available springs and other parts for the PRV assembly.