A pressure relief manifold for a jacketed, reaction vessel is designed to protect the vessel from breakage while isolated or disconnected from the circulator. Installed on the outlet side of the vessel, the manifold will reduce the likelihood of breakage caused by an excessive pressure differential exerted by the thermal transfer fluid. Complete system includes aluminum body, outlet fittings, hose, relief valve set at 10psi and pressure gauge. Designed for process scale reactors, 10 liter & above. Operating range -195 thru 426 degrees C.