Type I and II Treatment Systems (Electroscan, Purasan, Lectra/San): Care, Salt, Tablets and Winter

Find the treatment unit (usually a plastic box near the toilet) and its USCG certification label. Write down the brand, model, voltage and serial number, and photograph the label and control panel. Raritan points out that the Lectra/San and Electroscan are treatment units, not toilets: the toilet is a separate product with its own parts and manual. Note whether your boat also has a holding tank and a Y-valve, and where each seacock is.

Read the panel's lights or display section in the manual before you need it. Electroscan controls monitor how hard the electrodes are working and show a fault when treatment isn't adequate (for example low salt, low voltage or a blown fuse). Purasan units show cycle and tablet status. A unit that shows a fault is not treating properly, so don't keep discharging; switch to the holding tank if you have one, or stop using the head until it's fixed.

Raritan says the Electroscan must be operated with every flush; skipping cycles leads to clogging and possible damage. On most installations the toilet and treatment control are linked, but on some you press the treatment button first and then flush within a short window. Teach every guest the routine and post a short note in the head. Use only the amount of toilet paper the toilet maker recommends, and never flush wipes, paper towels or feminine products.

Electrode-type units are designed around full-strength seawater. In fresh or brackish water, or with a freshwater-flush toilet, the unit can't make enough disinfectant and will show a low-salt fault. Raritan's options:

• a salt feed unit that brings the flush water up to seawater salinity, filled with solar salt or water-softener salt pellets
• for Raritan toilets only, adding a small amount of granulated salt to the bowl before each flush (check with the toilet maker before doing this with another brand)

Keep the salt feeder topped up and its lines clear. Raritan also notes that if you mostly boat in fresh water or use freshwater flush, the tablet-based Purasan is the better match.

Purasan units dose disinfectant from tablets (older models used a cartridge or liquid) through a remote dispenser filled by the boat's pressurized fresh water during each cycle. Raritan's FAQ says a tablet typically lasts around 50 cycles, but the water level in the dispenser changes that. Check the dispenser often (EPA notes that most manuals for chlorine-tablet systems advise checking the tablet supply every week or two while the system is in regular use), keep spare tablets aboard, and keep the freshwater system turned on when the head is in use. Use only the tablets made for your unit; don't substitute pool or household chlorine products, and store tablets dry, sealed and away from fuel, oil and acids.

Low voltage is a common cause of poor treatment and fault lights. With the unit running its treatment cycle, measure the voltage at the treatment unit's terminals and compare it with the battery. Raritan's troubleshooting for the Lectra/San EC says the voltage at the unit during the second part of the cycle must not drop below 11.5 volts on a 12-volt system; check your own manual's figure. A big drop between battery and unit means corroded connections, a weak battery or undersized wire. Run the charger or engine while the system works, and have a marine electrician fix wiring problems.

Calcium scale on the electrode plates reduces treatment and shortens electrode life. Raritan lists failing to clean the electrodes every six months among the reasons electrodes wear out early, along with low salinity, water colder than about 50°F and toilet cleaners that coat the plates. Follow your manual's clean-out procedure exactly: breaker off, unit drained, the cleaning solution and soak time it specifies, and new gaskets if the manual calls for them. Look at the plates while they're out; damaged coating means the electrode pack needs replacing.

Raritan recommends only its own bio-active bowl cleaner for its toilets and treatment systems, and warns that cleaners with pine oil, formaldehyde, chlorine, phosphoric acid, solvents or petroleum can damage plastic and rubber parts. Harsh cleaners can also coat electrodes or upset the treatment chemistry. Raritan does say its holding-tank odor product can be used with the Electroscan and Purasan. If your unit is a different brand, follow its list.

Raritan recommends keeping the treatment unit within about six feet of the toilet, so untreated waste doesn't sit in a long hose and smell. If your hose run is longer, odor-resistant sanitation hose helps. If the unit sits higher than the toilet, a vented loop slightly above the unit's top keeps waste from flowing back. Rub a clean damp cloth on the hoses: if the cloth smells, the hose is permeated (see the head hose and sanitation hose guides). A clogged vented loop valve can cause siphoning and back-flow.

Before you enter an NDZ (or a landlocked lake), secure the system so nothing can go overboard. 33 CFR 159.7 lists the accepted ways for Type I and II devices: close the seacock and remove the handle, padlock the seacock closed, hold it closed with a non-releasable wire tie, or lock the door to the head with a padlock or keyed handle. If you have a Y-valve to a holding tank, set it to the tank and secure the overboard side. Inside the zone, use the holding tank and a pump-out station. Never hold waste in the treatment unit and dump it on the way out of a zone without running full treatment cycles.

Raritan is clear: antifreeze must never go into its treatment systems. Instead, the unit is flushed with clean water and pumped or drained dry, following the winterizing steps in the owner's manual for your model. Winterize the toilet with non-toxic antifreeze only if the manual allows it and only with the treatment unit isolated or bypassed as described there; some installations require the toilet to be done with fresh water and pumped dry too. Remove Purasan tablets for storage if the manual says so, drain the salt feeder, and switch off the breaker. In spring, check hoses and clamps, fill the salt feeder or dispenser, and run a few test cycles before the first guest uses the head.

Record salt refills, tablet changes, electrode cleaning dates, fault codes and voltage readings in BoatMend. A fault that shows up more often over a season (especially low salt or low voltage) is an early warning that electrodes, wiring or batteries are getting tired.