For use in closed, domestic hot water systems to control pressure buildup;Fixed diaphragm construction;Designed and constructed per ASME Code Section VIII, Division 1;Tested to JIS Z 2801 for reduction of Legionella, Staphylococcus and E. coli;Follows ASHRAE 188 Anti-Legionella guidelines;All models available with optional sight glass;Seismic restraints available on stand models only;Deep drawn models are lighter, stronger and more compact than traditional head and shell construction;Maximum Operating Temperature-200 Degree F;Maximum Working Pressure-150 PSIG;Warranty-1 Year