A diaphragm pump refills the pressure tank to 7 bar / 100 psi when in the tank pressure drops below a certain limit (5bar/75psi by default). Diaphragm pumps are positive displacement pumps that are capable of self-priming, meaning they can remove air from the water lines as long as the discharge side is unrestricted. Another useful feature is flow-back prevention, fluids cannot return from the discharge to the suction side.
12V - 3A DC diaphragm pump
Power input: 12V DC power source capable of delivering a minimum of 3 Amps (36W). Connected through a relay that is controlled by the Aero module.
Suction side: Connects to the Aeroponics tote's pre-filter through a 1.5 meter/ 5 ft washing machine hose with a 3/4" threaded connector.
Discharge side: Marked with an arrow in the pump head. Connects to the pressure tank's Pump input using a 0.5 meter/ 1.5 ft washing machine hose with a 3/4" threaded connector.
When selecting the pump choose one that has a built-in pressure switch to cut power in case the pressure gets too high. Mine came with the adjuster not set properly and the pump kept shutting down at 5 bar / 75 psi, if this happens to you too turn the adjuster screw clockwise until the cutoff point is at 7.2 bar / 105 psi. Do not go above this pressure as around 8 bar / 116 PSI the pump head will start to leak slightly.
A thermal kill switch was added to protect the pump from overheating. The switch is connected in series with the pressure protection switch and it cuts power if the temperature exceeds 60 °C / 140 °F until the pump cools down. The normally closed thermostat switch is installed on the positive DC input cable, a self-adhesive thermal pad creates contact between the sensor and the motor housing.
High-pressure diaphragm pump
7 BAR / 100 PSI, 12V - 3A (36W)Built-in check valve, adjustable cut-off switch, 5/16" barb connector
Thermal switch connected to the power line
Self-adhesive thermal pad to create contact
Chop a 2 meter / 6 feet washing machine hose into:
1.2m/ 4ft piece with the 90-degree connector for the suction side. Connected to the aeroponics tote's Pre-filter.
0.8m /2ft piece with the straight connector for the discharge side. Connected to the pressure tank's Pump intake
Install hose clamps on both suction and discharge sides to secure the two pieces to the pump. As the 5/16" diameter barb connectors on the pump are smaller than the washing machine hose's internal 3/8" diameter pull an extra piece of 5/16" tubing on the connectors before attaching the washing machine hose.
5/16" tubing to increase the size to 3/8"
Hose clamp securing the connection
Power to the pump will be provided from the Aeroponics module. To transfer the 12V - 3A required to drive the pump we need an extender cable, waterproof power connectors, and 2 pairs of terminal blocks to connect the pump wires to the waterproof DC connectors.
Terminal block connecting the waterproof DC power connector
Extender cable will be installed between the pump and the Aeroponics module
Pump mounted above the pressure tank, below the aeroponics weight platform and the Aero-module
