Attwood MK2 Shower Sump System 12V 800GPH Automatic Large Box

Attwood MK2 automatic shower sump system – 12V, 800GPH

A large-box grey-water collection and discharge system for showers, sinks, galley drains and air-conditioning condensate. An internal float switch starts the 800GPH pump automatically as the water level rises, while the clear snap-in lid and removable mesh screen simplify inspection and cleaning.

Suitable applications: motorboats, yachts, canal boats, liveaboards, campervans and other 12V installations requiring contained grey-water drainage.

Technical specification

Boat compatibility and system design

• Collects grey water from one or more showers, basins, galley sinks or condensate drains.
• For 12V electrical systems only; not compatible with 24V supplies without a suitable converter.
• Verify the available mounting space, inlet heights, hose diameters and discharge route before purchase.
• Not for toilet waste, fuel, oil, drinking-water delivery or heavily contaminated liquids.
• The discharge must be routed to an approved above-waterline outlet with anti-siphon protection where required.

Important: nominal flow is measured under low-restriction test conditions. Installed output reduces with vertical lift, hose length, small-bore pipe, bends and fittings.

Installation, checks and package contents

• Mount level, upright and accessible so the lid, screen, float and pump can be serviced.
• Use the correct inlet adaptor for every connected drain and blank any unused openings securely.
• Keep discharge hose runs short and rising, avoid sags and restrictions and provide a vented loop where the installation requires it.
• Connect through the recommended fuse and test automatic start, shut-off, leakage and backflow before use.
• Attwood reference 5143-4; legacy 4143-4 applications should be compared for box dimensions and connection positions.

Package contents: one genuine Attwood large-box shower sump assembly with internal 12V pump, float switch, clear lid, filter and supplied connection parts.

Frequently asked questions