Dual-function pump marine toilets draw their flush water from a sea bird or water tank and pump the waste either to another sea bird or a holding tank. Its capacity to pump waste generally exceeds its capacity to pump water, which means the bowl is completely empty.
Hoses and Connections
It is important to only use high quality sanitary hose. All flexible hoses are permeable to some extent, and only a high-quality, sanitary hose will be able to control odor (smelly gases can completely saturate a lesser-quality hose, creating a foul odor for months after all the waste has been removed). All connections must be double-hose (with the clamps facing each other). It is recommended to carefully use the heat gun to soften the hose ends. Use quality and all stainless steel clips/clamps and the subject joins the "pull test".
Large hoses put great stress on connections, and the result of a failed connection can be more than unpleasant – failed underwater connections sink boats! Rigid PVC (domestic) pipes should be avoided – they are not designed to handle the stresses caused by the boat moving in the seaway.
Avoid contractions caused by small installations and sharp bends. Some seacock valves are too tight - use full flow types where possible.
Do not bend hoses too tight. The minimum bending radius of our sanitary hose is approximately 125mm for 25mm hose, 190mm for 38mm hose. Not only do severe bends lead to hose failure (often in places that are difficult to see or reach), they also put undue stress on the connections. Use 90 degree bends if necessary. Stretching (on the outside of the hose's narrow bend) also increases the permeability of the hose, which leads to unwelcome results.
Protect hoses from chafing. Support long runs of hose at regular intervals using multiple straps. Also, protect the hose where it passes through baffles.
Note on Equipment
We recommend true design fittings where possible, for the following reasons:
No ground bond required after installation
No corrosion problems linked to electrolysis
It is as strong as copper fittings
Electrical Connection
Toilet pumps use surprisingly little energy given their short operating times. However, when in use, the demand can be more than 200 watts (up to 20 amps on a 12 volt system). The size of the supply cable must at least match that supplied with the motor and switch. Cables longer than 3-4 meters should be larger in size to avoid voltage drops and overheating. Install the fuse switch box in plain view and easily accessible to the toilet user.
When Connected to Holding Tank
If the tank is located below the toilet, it is necessary to create a water trap to prevent unpleasant odors from the tank from circulating back through the toilet. This is achieved by having a lever ring in the outlet hose (about 400mm minimum height for manual toilets, 300mm minimum height for electric toilets) which will hold enough water at the base of the toilet to form a trap. Instead, you'll need to install or set up a trap elsewhere in the line.
Toilet at or below Outside Water level
It is normal and safe for boats to close all sea birds when there is no one on board. However, when the seacocks are open, the toilet valves/seals and impellers (which are subject to interference and aging/hardening) cannot be relied upon to prevent seawater from being drawn into the toilet, and then into the boat. Manual toilets have a 'dry bowl' lever to shut off the water supply, and every person on board should be instructed to turn this off after use. Only electric toilets have a rubber flush to prevent backflow. Even when all parts are in new condition, there is serious danger.
If the marine toilet has a direct or indirect connection to the sea, we strongly recommend installing vent loop (siphon separators), especially at the waste outlet. Even if Seacock valves are easy to access (and routinely used), failing to install SIPHON-breaks could sink your boat!
A note about flush siphon separators: Under suction, normal vent rings will allow air into the system, removing the rigging and preventing the pump from drawing any flush water. To prevent this from happening, you might consider using a line valve instead, in an accessible location. But the best option, especially with electric toilets, is a solenoid-controlled aeration loop, which can be connected to the toilet switch to provide automatic operation (see below).
The Toilet is above the Outside Water Level
Running water can be drawn for several meters, and up to a meter in height. However, note that water can drip off, causing the pump to deactivate between uses. A non-return valve close to the tank can solve this problem, but it requires a good head of water at the top (through a rising loop) to keep it working. If a lift ring is not practical, a manually operated inline valve or electrically controlled solenoid valve (connected to the toilet switch) may be needed in the flush water supply line.
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