Jabsco Cyclone 50840 Series Low Pressure Centrifugal Pump, Stainless Steel, 29 GPM, 8.7 PSI

Overview

The Jabsco 50840 Series is a low pressure centrifugal pump for marine circulation jobs where a high flow of clean water is needed without high discharge pressure. This stainless steel DC motor and pump unit is used for installations such as hot water circulation, livewell circulation, and bait tank systems, with versions for 12VDC or 24VDC boats and 3/4" NPT or 3/4" BSP pipe threads.

Across the 50840 low pressure variants, the pump is continuously rated and delivers 31 GPM (120 LPM) open flow with maximum pressure of 9 PSI (0.6 BAR). It uses a mechanical seal, anti-clog impeller design, and stainless steel construction, which makes it a practical fit for wet compartments where vibration, heat, and frequent use are part of normal service.

Key features

• Low pressure centrifugal pump range with 31 GPM (120 LPM) open flow and 9 PSI (0.6 BAR) maximum pressure across the 50840 variants.
• 12VDC and 24VDC versions let the pump match common DC electrical systems on boats.
• 3/4" (19 mm) NPT or BSP port fittings support the pipe thread standard used in the installation.
• Continuously rated motor with a 3500-hour motor life rating for circulation jobs that may run for long periods.
• Stainless steel construction with an anti-clog impeller design and long-life mechanical seal.
• Can run dry for short periods and can run against a closed discharge.
• Single-tool servicing keeps seal or pump-head work straightforward on board.

Variants

The product is offered in four configurations so it can match the boat voltage and the pipe thread standard used in the plumbing system.

The available configurations vary by voltage and port fitting. The low pressure rating, 31 GPM (120 LPM) open flow, 9 PSI (0.6 BAR) maximum pressure, and continuous duty rating remain common to these four versions.

• 50840-0012: Voltage 12VDC, port fitting 3/4" NPT. This configuration is for 12V DC systems using NPT threaded plumbing.
• 50840-2012: Voltage 12VDC, port fitting 3/4" BSP. This configuration is for 12V DC systems using BSP threaded plumbing.
• 50840-0024: Voltage 24VDC, port fitting 3/4" NPT. This configuration is for 24V DC systems using NPT threaded plumbing.
• 50840-2024: Voltage 24VDC, port fitting 3/4" BSP. This configuration is for 24V DC systems using BSP threaded plumbing.

Installation and setup

The Cyclone can be mounted on any flat surface. For proper operation, place the pump below the lowest fluid level so the pump head stays flooded; this is important because centrifugal pumps depend on liquid being available at the inlet.

Fit the pump in a location that stays dry and has ventilation. Use the rubber grommets to reduce vibration transfer into lockers, bulkheads, or machinery spaces. When the pump is mounted vertically, keep the motor above the pump head.

Use 3/4" pipe fittings with PTFE pipe joint tape or compound. Plastic fittings should not be used if the pump is installed below the waterline.

Electrical and system integration

Select the variant that matches the vessel DC supply before wiring. The 12VDC models are for 12V systems, and the 24VDC models are for 24V systems; a low battery or undersized wiring can reduce pump output.

Wire polarity matters. Connect the positive lead to the red or orange conductor and the negative lead to the black conductor. If polarity is reversed, the pump may still run but output can be poor. Protect the circuit with the correctly rated fuse or circuit breaker for the selected model.

Operation and service

The pump may run dry for short periods and may run against a closed discharge. Those capabilities are useful during brief priming or valve transitions, but normal operation should keep the pump supplied with fluid.

Service access is straightforward because the pump head can be worked on with a single tool. Periodically check the electrical connections and inspect the seal area for signs of leakage, especially after heavy use or a long layup.

Use cases on board

This pump suits boat owners and technicians setting up livewell circulation, bait tank flow, or hot water circulation where continuous DC operation is required. It is also useful as a general circulation pump in marine systems that need strong flow at low pressure rather than a pressure pump for taps or washdown.

Safety notes

Do not use this pump for petrol or fluids with a flash point below 37.8 C (100 F). For overboard discharge installations, the discharge outlet must be above both the static and heeled waterlines to reduce flooding risk.