Frequently Asked Questions
At Aquastar Distributors we carry an extensive line of Dometic products for marine sanitation. These products include VacuFlush and MasterFlush systems. Additionally, we carry Guidi brass fittings and General Ecology water filtration products. Given our varied product line, we receive many questions that range from specific parts selection, to how some of the entire systems work. We have put together this FAQ page to address many of these.
VacuFlush Systems – Basics and Operation
How does a VacuFlush sanitation system work?
A Dometic VacuFlush system operates using a vacuum generator (pump) that builds and stores vacuum pressure in a tank. When you flush—via pedal or electronic switch—the system releases this vacuum, instantly pulling waste and a small amount of fresh water through the lines into the holding tank. This creates a powerful, odor-free evacuation without relying on gravity or maceration, while minimizing water and electrical use. At AquaStar, we stock all the parts and components you need to keep your system running smoothly, as well as for new installations.What is the difference between VacuFlush and macerating toilets?
VacuFlush is a vacuum-based system that stores negative pressure for quick, low-water flushes (often just 0.5 liters, 16 oz), relying on suction to evacuate the bowl and prevent odors without a traditional water seal—ideal for odor-sensitive marine/RV environments. Macerating toilets, in contrast, use an electric pump to grind (macerate) waste before pumping it out, typically requiring more water (1-2 liters, 0.5+ gallons) and featuring a water seal for better long-term odor control, but they can be noisier and less efficient in tight spaces. Choose VacuFlush for water savings and reliability; we carry both Dometic VacuFlush and compatible macerator options for upgrades. Macerating heads are better suited to larger bots, with fewer power and water-use constraints.How do I operate a pedal-flush VacuFlush toilet?
To add water to the bowl (for solids or cleaning), lift the pedal slightly or press it halfway down until the desired level is reached. To flush, press the pedal fully down for at least 3 seconds to open the flush ball and release the vacuum, thereby evacuating the contents. Let the pedal snap back up to seal the bowl properly. Ensure the system’s power and water supply are on, and listen for the vacuum pump to recharge (about 20-30 seconds). Check out the YouTube video below for additional tips.How do I operate an electronic VacuFlush toilet?
Use the wall-mounted flush switch or electronic handle: Press the “Add Water” button to fill the bowl (hold for desired level, typically before use). Then, press “Flush” to activate the vacuum, evacuating waste in seconds. Some models have “Normal” or “Low” modes for water control, and status lights indicate vacuum readiness (green) or issues (red). Always ensure electrical power and fresh water are supplied before use. For additional information, you can use the link below to view the VFS manual or watch our how-to video.
How much water does a VacuFlush toilet use per flush?
A Dometic VacuFlush toilet typically uses about 1 pint (0.5 liters) of fresh water per flush, though this can vary from 0.4 liters in low-water modes to 1 liter for thorough rinses, depending on flush duration and model settings. This efficiency maximizes holding tank capacity (up to 4x more than macerators) and reduces odors—perfect for extended marine or RV trips. Check our VacuFlush lineup for water-saving options.Does VacuFlush use fresh water or seawater?
Dometic VacuFlush systems are designed to use fresh water from your onboard supply, which helps prevent odors from decaying organisms in seawater and reduces calcification buildup in hoses, extending system life. It is possible to connect a Vacuflush System to seawater; the water must be pressurized, and an external strainer with 100-mesh openings or smaller is required.What is the vacuum tank and is it full of black water?
The vacuum tank in a Dometic VacuFlush system stores vacuum pressure (energy) generated by the pump, which is used to evacuate the toilet bowl during flushing; it includes a vacuum switch to monitor levels and is not filled with black water, but the waste does move through the tank before entering the separate holding tank. For compact setups, check our Dometic Vacuum Holding Tanks (VHT) that combine functions without compromising performance.How long does it take for the vacuum to recharge after flushing?
After a flush, the Dometic VacuFlush system typically recharges the vacuum in about one minute, though this can vary slightly based on hose length and system configuration—indicated by optional status lights turning from red (“Do Not Flush”) to green when ready. This quick recharge supports efficient use in marine or RV environments; we carry vacuum pumps and switches to ensure your system stays responsive.Can I flush toilet paper in a VacuFlush system?
Yes, you can flush toilet paper in a Dometic VacuFlush system, but only rapid-dissolving marine-grade tissue to avoid clogs—specialized options like Dometic’s 1-ply or 2-ply break down quickly in the vacuum lines. Using the right paper prevents buildup and maintains flow; stock up on compatible toilet paper and maintenance kits from AquaStar for hassle-free operation.
Can tampons or other foreign objects be flushed in VacuFlush?
No, do not flush tampons, sanitary napkins, wet wipes, flushable wipes, or other foreign objects in a Dometic VacuFlush system, as they can cause clogs in the vacuum pump or lines, leading to malfunctions and costly repairs. Stick to bodily waste and approved toilet paper only—our Dometic repair parts, like duckbill valves, are available to fix issues if they arise.Why choose a VacuFlush system for my boat or RV?
Dometic VacuFlush systems are ideal for boats and RVs due to their efficient fresh water and electrical usage, which eliminates odors and calcification from seawater, providing a compact, reliable setup that reduces installation time and uses minimal electricity (8-8 amps per flush). The vacuum technology ensures powerful, odor-free flushes with low water consumption, making it perfect for extended trips where space and resources are limited—browse our Dometic VacuFlush lineup for models suited to your vessel or vehicle.How do I start up a VacuFlush system?
To start up a Dometic VacuFlush system, turn on the power to the vacuum pump and let it cycle to build vacuum (listen for it to stop running, indicating readiness); check seals at the pump-to-accumulator tank connection, then perform an initial flush with a full bowl of water to rinse the lines. This ensures proper operation—keep genuine Dometic parts on hand from AquaStar for any rebuilds or maintenance.What happens if the holding tank is full?
Dometic’s Sanitation systems can be installed in a variety of different ways. Generally when the holding tank in a Dometic VacuFlush system reaches full capacity (equipped with a sensor or tank monitor), a red “full” light illuminates, and the vacuum pump automatically shuts down to prevent overflow until the tank is pumped out. This safety feature protects the system; monitor tank levels regularly and use our compatible holding tank sensors for reliable alerts. Use Dometic’s Maxcontrol Natural to prevent waste build-up on the tank monitor’s sensors.
How does the pump-out work with VacuFlush?
Pumping out for a Dometic VacuFlush system involves connecting an external dockside or portable suction pump to the holding tank’s deck fitting. This pump evacuates the waste from the holding tank. For optimal results, ensure the vent line is clear—shop AquaStar for vent filters and pump-out accessories.