12V Potable Water Pump VEVOR NMDP52 Series

Quick Guide

The VEVOR 52 Series is a heavy-duty, 5-chamber diaphragm pump designed for pressurized water systems in yachts, RVs, caravans, and other applications. It features a built-in bypass function to reduce rapid cycling and is capable of self-priming and running dry.

Specifications

• Rated Voltage: 12V
• Rated Pressure: 70 PSI
• Max Flow: 5.0 GPM (NMDP52-G50-70-12) or 5.5 GPM (NMDP52-G55-70-12)
• Inlet/Outlet Diameter: 1/2" MNPT

Installation

Materials Required: Diaphragm pump, flexible reinforced hose (min 1/2" ID), stainless steel hose clamps, screws, electrical cut-off switch, fuse, screwdriver, and sealant/Teflon tape.

1. Mounting: The pump can be mounted in any position. If mounted vertically, the pump head must be in the down position to prevent leakage into the motor casing. Secure the feet without over-compressing them to maintain vibration dampening.
2. Plumbing: Use 1/2" ID reinforced hoses. Avoid kinks or restrictive fittings. Install a strainer on the inlet side. If using a check valve, ensure it has a cracking pressure of no more than 2 psi.
3. Electrical: Connect to a dedicated circuit. Connect the red (positive) lead to the battery positive terminal and the black (negative) wire to the negative terminal. Install an accessible switch to control power. The circuit must be protected by a 15-amp fuse.

Adjusting the Bypass Valve and Pressure Switch

Caution: Bypass adjustment should be performed by a professional technician using proper gauges. Improper adjustment can damage the pump.

1. Remove the pressure switch cover.
2. Use a 2mm wrench to adjust the pressure adjustment screw (No. 2). Turn clockwise to increase pressure, counterclockwise to decrease.
3. Adjust the bypass valve screws (No. 3) accordingly. Turn clockwise to increase pressure, counterclockwise to decrease.
4. The pressure setting for full bypass must be at least 8 psi higher than the shut-off pressure of the pump.

Troubleshooting

• Pulsating Flow: Check lines for kinks, ensure plumbing is not too small, clean filters, and check for air leaks.
• Failure to Prime: Check for air leaks in the intake, debris in valves, punctured diaphragm, or insufficient voltage.
• Motor Won't Start: Check for loose wiring, blown fuse, failed pressure switch, or defective motor.
• Pump Won't Turn Off: Check for leaks in the discharge line, punctured diaphragm, or defective pressure switch.

Maintenance

Regular maintenance and winterization are essential, especially before and after storage. Do not adjust the bypass valve personally without professional assistance.