2 gyinabea anaa 2 kwan solenoid valves taa yɛ closed, direct acting solenoid valves na enhia sɛ ɛba fam koraa differential nhyɛso na adwuma. Sɛnea wɔakyerɛ wɔ mfonini a ɛwɔ aseɛ ha yi mu no, sɛ coil no yɛ de-energized (benkum so mfonini) a, plunger no gyina orifice kɛseɛ no so na plunger spring force no kura mu, na ɛsɔ valve no ano. Sɛ coil no nya ahoɔden (nifa so mfonini) a, solenoid no ma plunger no so na ɛma adwumayɛ kwan no tumi fa orifice no mu. Wɔakyerɛ adwumayɛ medium ne flow direction wɔ purple mu wɔ mfonini no mu.
