For some reason, simplehuman won’t tell you this, but if your soap dispenser starts dispensing air instead of soap, or it dispenses less soap than it used to:

• Pour the soap out of the soap cartridge.
• Fill the cartridge with hot water from your faucet
• Turn the unit on and re-prime the pump by completely covering the sensor window, then pressing the power button 3 times quickly.
• Note that this will make the pump run continuously until the sensor window is uncovered.
• Run the hot water through the pump until you see the flow change to a faster speed. You’ll know when it happens. In our case, it took 1/3 to 1/2 of the water in the cartridge.
• Pour the water out.
• Fill the cartridge with soap.
• After a few watery dispenses, your dispenser will be back to its previous glory.