What's Involved In Winterizing A Marine Watermaker?

Marine watermakers are essential equipment for long-distance sailors and liveaboards, providing fresh drinking water wherever you go. However, when boating season ends and temperatures drop, these systems require special attention to prevent damage during periods of inactivity. Proper preparation ensures your equipment will be ready to perform when you need it again.

This guide walks you through the complete winterization process, covering why it matters, the step-by-step flushing procedures, antifreeze application, component protection, and storage considerations. By following these practices, you'll extend the life of your watermaker and avoid costly repairs come spring.

Understanding Why Winterization Matters

When water sits idle in a watermaker system during cold weather, several problems can develop. The most significant risk is freezing, which can crack membranes, damage pumps, and rupture fittings. Even in climates where temperatures don't drop below freezing, stagnant water creates an environment for biological growth that can foul membranes and reduce system efficiency.

Salt water left in the system crystallizes as it evaporates, leaving behind deposits that can clog small passages and damage sensitive components. The high-pressure pump and membrane are particularly vulnerable to these effects. Without proper preparation, you might return in spring to find your system needs expensive repairs or complete replacement.

Taking time to properly prepare your marine watermaker for winter protects your investment and ensures reliable performance for years to come. The process typically takes just a few hours but saves you from potential headaches and significant expenses down the road.

Flushing the System Thoroughly

The first step involves removing all salt water from the system. Start by running fresh water through the entire watermaker for at least 30 minutes. This initial flush removes the majority of salt and mineral deposits that could cause problems during storage. Make sure the system runs at normal operating pressure during this process to reach all internal passages.

After the initial freshwater flush, many boaters perform a pickling procedure using a specialized cleaning solution. This involves circulating a biocide solution through the system to eliminate any bacteria or organic matter that might grow during storage. The solution should remain in contact with all wetted surfaces, including the membrane, for the manufacturer-recommended time period.

Once the cleaning solution has done its job, perform a final freshwater flush to remove any residual chemicals. This step is important because you don't want cleaning agents sitting in the system for months. Run clean fresh water through until it comes out clear and you can't detect any chemical smell in the discharge.

Adding Antifreeze Protection

After flushing, you'll need to introduce antifreeze to prevent freeze damage in cold climates. Use only non-toxic propylene glycol antifreeze specifically designed for potable water systems. Never use automotive antifreeze, as it's toxic and will contaminate your drinking water system.

Mix the antifreeze according to the manufacturer's specifications for your expected low temperatures. In most cases, a 30-50% solution provides adequate protection for typical winter conditions. Circulate this mixture through the entire system, including all hoses, filters, and the membrane housing, until you see pink antifreeze coming out of the discharge.

Pay special attention to low points in the system where water might collect, such as the bottom of the membrane housing or pump inlet. Some systems have drain plugs that should be opened to ensure complete antifreeze coverage. The goal is to displace every bit of water with the protective solution.

Protecting Components and Seals

Beyond fluid protection, physical components need attention during the winterization process for watermakers. Remove and inspect all filters, checking for wear or damage. Clean or replace them as needed, and store them in a dry location. Leaving dirty filters installed can lead to contamination and reduced performance later.

Inspect all seals, O-rings, and gaskets for signs of wear, cracking, or compression set. These rubber components can dry out during extended storage, so consider applying a thin coat of appropriate lubricant to preserve their flexibility. Replace any questionable seals now rather than dealing with leaks when you recommission the system.

Disconnect electrical connections and protect them from moisture and corrosion. If your system has an electronic control panel, ensure it's powered down completely. Some owners prefer to remove sensitive electronics and store them indoors where temperature and humidity remain stable throughout the winter.

Storage and Maintenance Checks

Choose your storage location carefully. The ideal spot is dry, temperature-controlled, and away from direct sunlight. If you must leave the watermaker installed on the boat, ensure adequate ventilation around the unit to prevent condensation buildup. Cover the system with a breathable material that protects from dust but allows air circulation.

Label all hoses and connections before disassembly if you're removing any components. Take photos of the system configuration to help with spring reinstallation. Keep all loose parts, filters, and accessories together in a labeled container so nothing gets misplaced over the winter months.

Document what you've done, including dates, products used, and any issues you noticed. This record helps track maintenance history and reminds you of specific steps when you reverse the process in spring. Note any parts that might need replacement so you can order them before the next season starts.

In Conclusion

Winter preparation for marine watermakers involves systematic flushing, antifreeze protection, component care, and proper storage. Each step plays a role in preventing damage from freezing, salt crystallization, and biological growth. While the process requires attention to detail, it's straightforward and protects equipment that represents a significant investment in your vessel's capabilities.

Whether you're planning extended cruising or coastal sailing, having a reliable watermaker gives you independence and flexibility on the water. Our team at EcoSistems specializes in energy-efficient reverse osmosis watermakers designed for optimal performance and easy maintenance. Get a free quote for a marine watermaker and discover how our advanced technology can enhance your boating experience for seasons to come.