A solenoid operated modular valve (10; 85; 116; 166), comprising: a solenoid body having a coil and a pole piece positioned in the solenoid body; a polymeric material valve body cartridge (14; 124) releasably connected to the solenoid body; and an armature/valve member (36; 118) slidably disposed in both the solenoid body and the valve body cartridge (14; 124), the armature/valve member (36; 118) displaced toward the pole piece when the coil is energized, characterised in that the solenoid operated modular valve (10; 85; 116; 166) further comprises: a polymeric snap-in seat assembly (18; 88; 137; 168) having: first and second deflectable claw arms (70, 72; 138, 140; 174, 176) each having a barb (74, 76; 178, 178') engaging the valve body cartridge (14; 124) to retain the snap-in seat assembly (18; 88; 137; 168) in direct contact with the valve body cartridge (14; 124); a guide tube slidably receiving a valve member guide of the armature/valve member (36; 118); and a biasing member (42; 136) acting to normally bias the armature/valve member (36; 118) toward the snap-in seat assembly (18; 88; 137; 168) and acting to create a clearance gap between the snap-in seat assembly (18; 88; 137; 168) and the valve body cartridge (14; 124) in a non-installed condition of the modular valve (10; 85; 116; 166). a solenoid body having a coil and a pole piece positioned in the solenoid body; a polymeric material valve body cartridge (14; 124) releasably connected to the solenoid body; and an armature/valve member (36; 118) slidably disposed in both the solenoid body and the valve body cartridge (14; 124), the armature/valve member (36; 118) displaced toward the pole piece when the coil is energized, characterised in that the solenoid operated modular valve (10; 85; 116; 166) further comprises: a polymeric snap-in seat assembly (18; 88; 137; 168) having: first and second deflectable claw arms (70, 72; 138, 140; 174, 176) each having a barb (74, 76; 178, 178') engaging the valve body cartridge (14; 124) to retain the snap-in seat assembly (18; 88; 137; 168) in direct contact with the valve body cartridge (14; 124); a guide tube slidably receiving a valve member guide of the armature/valve member (36; 118); and a biasing member (42; 136) acting to normally bias the armature/valve member (36; 118) toward the snap-in seat assembly (18; 88; 137; 168) and acting to create a clearance gap between the snap-in seat assembly (18; 88; 137; 168) and the valve body cartridge (14; 124) in a non-installed condition of the modular valve (10; 85; 116; 166). a polymeric snap-in seat assembly (18; 88; 137; 168) having: first and second deflectable claw arms (70, 72; 138, 140; 174, 176) each having a barb (74, 76; 178, 178') engaging the valve body cartridge (14; 124) to retain the snap-in seat assembly (18; 88; 137; 168) in direct contact with the valve body cartridge (14; 124); a guide tube slidably receiving a valve member guide of the armature/valve member (36; 118); and first and second deflectable claw arms (70, 72; 138, 140; 174, 176) each having a barb (74, 76; 178, 178') engaging the valve body cartridge (14; 124) to retain the snap-in seat assembly (18; 88; 137; 168) in direct contact with the valve body cartridge (14; 124); a guide tube slidably receiving a valve member guide of the armature/valve member (36; 118); and a biasing member (42; 136) acting to normally bias the armature/valve member (36; 118) toward the snap-in seat assembly (18; 88; 137; 168) and acting to create a clearance gap between the snap-in seat assembly (18; 88; 137; 168) and the valve body cartridge (14; 124) in a non-installed condition of the modular valve (10; 85; 116; 166).