Freshwater plumbing A little spring maintenance will keep the clean water running
Afew years ago, I had one of those heartfelt conversations familiar to all boat owners, the kind where you figuratively sit at the feet of the best guru in the boatyard, eyes gleaming with hope that he can get to the root of a perplexing boat problem.
“The freshwater pump works fine for a while,” I said. “Then it cycles on, shuts off and won’t start back up again.”
The guru rubbed his chin, asked a few questions.
“No, there’s no leakage,” I said. “The bilge is dry.”
More questions.
“No, it doesn’t happen all the time. Only sometimes.”
The guru shook his head. “You’ve got gremlins.”
“Gremlins?”
He nodded, his face grim. “They’re the worst,” he said.
So much for the great oracle. No help there, and none from the Shurflo manual. I’d read it. Seventeen times. I especially loved the part that said most problems were due to loose hose clamps. I went back to the boat, dejected and more puzzled than ever about the gremlins in my freshwater system. Resigned to coughing up the bucks for a new pump, I ordered one from West Marine. When it arrived I began taking out the old pump and discovered the problems I was having were caused by a faulty electrical connection.
While pressurized marine freshwater systems are relatively simple, they can be the source of immense frustration and inconvenience when they are on the fritz. After all, having water for cooking and washing is pretty important. It’s a clear case of you don’t know what you’ve got until it’s gone. Periodic maintenance and inspections go a long way in heading off potential trouble. In addition, expending a little extra effort will help ensure that the water you drink tastes good and is safe.
Water works A typical freshwater system includes an electric diaphragm pump to draw water from a vented tank. A strainer or filter is installed in the outlet hose between the tank and the pump to prevent debris from damaging the pump’s inner works. A manual pump is often installed in the outlet hose as well. I consider a manual pump an essential component of the freshwater system. It will serve as a backup if the electric water pump fails and it uses much less water when I’m away from the dock.
The outlet or discharge side of the electric pump is plumbed into an accumulator tank that stores pressurized water. Designed with a sealed air chamber and a water reservoir, these are also called expansion tanks because they allow for the expansion of water volume within the tank. They perform several functions, the most important of which is the reduction of water pump cycling when minor variations of pressure occur. In other words, the pump won’t cycle on every time a small amount of water is drawn from a faucet, saving amps and prolonging the life of the pump. The discharge side of the accumulator tank is plumbed into a manifold that directs cold water to faucets and the shower. The manifold also feeds cold water into the bottom of the water heater.
Problems in freshwater systems often arise shortly after spring commissioning. Hoses have been removed in the winterizing process, and those pesky clamps may be loose either because they weren’t tightened enough when reinstalled or because the hoses themselves have expanded and contracted as temperatures rose and fell while the boat was on the hard. Loose hose clamps will cause leaks, and they also will allow air to seep into the system and cause the pump to cycle continuously without delivering adequate water pressure.
You might think all is well for quite some time before enough air builds up, but you don’t need much to make trouble. A pinhole in a hose, a tiny tear from chafe, or a poorly seated hose clamp can all trigger continuous cycling, as can improperly installed water filters and sharp bends in supply lines. If the ends of your hoses at the manifold are chewed up from years of being pried off the hose barbs during winterizing, consider cutting the bad ends off provided there’s enough slack in the hose. Over time the plastic at the clamp point can harden and lose shape, preventing a tight seal at the barb. This is one area often overlooked when troubleshooting an erratic water pump. Just because you don’t see any leaks doesn’t mean the seal is tight enough.
Plumbing prescriptions When I commission the freshwater system aboard Sonata, my 1981 Pearson 36 cutter, I take several steps to avoid a visit to the boatyard guru and the possibility of bad-tasting water. The first thing I do is tighten the hose clamps at every connection, starting with the ones at the tanks. This involves some circus contortion acts to get at some of the hose clamps, but it’s well worth the effort. I frequently find clamps have loosened. In fact, I repeat the process later in the season, particularly after pronounced temperature changes or after a long passage; engine vibration can loosen clamps.
The strainer at the outlet hose from the tank is another part of the system worth checking. It must be clean and free of debris that could slow the flow of water on its way to the pump. Crud stuck in the strainer also can make water taste bad.
Freshwater pumps are designed to be maintenance-free. However, they still deserve a careful inspection before charging the system with water. Are the screws holding the pump in place all tight? Is the wiring neat and secured with cable ties, and are the connections all tight and free of corrosion? While I’m at it, I also check the accumulator tank to make sure it’s securely mounted.
The water heater is the next point of scrutiny. I’ve found that many skippers pay little attention to water heaters, until they fail, often from allowing galvanic corrosion to go unchecked for years. The typical water heater runs off a heat exchanger to heat the water when the engine is running, and when at the dock hooked up to shore power an AC heating element is used to heat the water. There are dissimilar metals in the heater and these can interact, causing galvanic corrosion. Stray current exacerbates the problem. A magnesium sacrificial anode built into the heater prevents galvanic corrosion from occurring, but it must be checked annually and replaced if necessary. If you haven’t seen your anode lately, check it before charging the system with water. You might be very surprised at what you find, or, worse, at what you don’t find.
On board Sonata, I have a six-gallon Raritan water heater, and I check the anode every spring. It’s a fairly simple operation involving the removal of the hot water lines on the manifold at the hot water discharge located at the top of the tank. The entire fitting unscrews from the tank, allowing for easy inspection or replacement. If the anode is less than three-eighths of an inch in diameter, it should be replaced. A badly corroded anode can discolor water or make it taste bad. After checking the anode, I go over the wiring and I make sure the tank is secured to its mounting plate. I clean the exterior of the tank with dish soap diluted in freshwater; solvents will harm the heater jacket.
Another item on the checklist is the secondary water filter, if one is installed in the system. Typically water filters are mounted at the cold water supply hose in the galley. Hot water destroys filter cartridges, so care should be taken to ensure that the cold water line always stays cold. In some cases it doesn’t when the engine is run for long periods. Before charging the system, replace the cartridge and fill the filter housing with water prior to reinstalling it.
Check the shower sump pump. Is the mesh screen over the filter clean? Are the electrical connections tight? Are the hoses in good shape?
Flushing out After I go through the above steps, I’m ready to flush the nontoxic antifreeze from the system. Once this is done and enough fresh water is added to the tanks to purge air from the lines, I check for leaks, and then I move on to cleaning the water tanks. This takes time, but it’s worth the effort in savings on buying bottled water for drinking. There are plenty of tank cleaning potions and water treatments on the market, but I generally dilute about two-thirds cup of bleach in a gallon of fresh water for every 10 gallons of tank capacity. After filling the tanks and running all the faucets and the shower to charge the lines with the bleach solution, I wait for 24 hours, then pump all the water out.
A word of caution here: freshwater pumps aren’t designed for periods of extended use. Generally 15 minutes of continuous operation is about the maximum before you must turn the pump off and let it cool. It’s better to find a way to drain the tanks into the bilge and use the bilge pump to dump the water, as long as you’re sure the bilge is clean and free of oil, diesel or gasoline.
After the first step, I add one quart of white vinegar for every five gallons of tank capacity, run the solution through all the lines, and let it sit for two days. The white vinegar helps remove the taste of bleach from the water. I dump the water again, refill the tanks, and let the solution sit for another day before draining the tanks for the last time. At this point, the bleach will have killed off mold, algae, mildew and any bacteria in the tanks or lines.
Cleaning the tanks is a major factor in ensuring the water in the system tastes good, and so is using the water supply. Far too often water sits in tanks for extended periods, allowing it to get stale. Frequent use of the system will prevent this.
If the boat’s freshwater system doesn’t include a filter, consider adding one. Top quality filters will remove sediments, chlorine odors, bacteria, lead and parasitic cysts such as giardia and cryptosporidia. However, in most cases an ordinary inline, faucet, or bulkhead-mounted carbon filter will be more than adequate. Marine types are best, but any water filter for use in the home will also work as long as it’s made from materials that won’t corrode. Purchasing an FDA-approved water fill hose is better for your health and it won’t impart a nasty taste to the water like garden hoses.
Pressurized freshwater systems greatly enhance the quality of life on board. Taking the time to maintain and inspect them will keep the gremlins where they belong: on someone else’s boat.
