N.C. De-energised or N.O Energised: 2 to 1 full flow, pressure difference through the pilot orifice holds the main poppet open. 1 to 2 restricted flow, main poppet seated due to pressure differential. N.C. Energised or N.O De-energised: 2 to 1 No flow, pilot orifice closed, main poppet seated due to pressure differential. 1 to 2 full flow when the solenoid force is overcome.