Installation
Commissioning
After powering up the FlushRobot for the first time, it will automatically enter setup mode. If you want to invoke the setup mode later on, hold the Drain button of the power while powering up the FlushRobot.
If you invoked the setup mode by holding the Drain button, you have to release it any time after three seconds.
Once in the setup mode, the LED will light.
Setting the maximum bowl fill level
The maximum bowl fill level needs to be set, so that during the hose cleaning mode, this level can be used for the final flush. Once set, the built-in safety feature of the FlushRobot will make it impossible to exceed this fill level even manually, as the drain pump will engage automatically to prevent overfilling the bowl.
Setting the maximum fill level is based on time, as the FlushRobot has no means to sense the amount of water entering the bowl.
Perform this setup with a battery voltage which is somewhere in the middle of the normal operation window, like around 13.2 Volts. Avoid performing this procedure with voltages below 12.5V or above 14V. Double these voltages for 24V systems.
When setting the maximum bowl fill level, keep some reserve for rough sea conditions and/or heeling of the boat.
Within 30 seconds after the LED lights up, start filling the toilet bowl with the Fill button to the maximum level. Do not release the Fill button in between, hold it until the desired maximum fill level has been reached, then release the button.
Immediately after releasing the fill button, the drain pump will be activated. During this process, it will record the electrical current through the pump as a reference, and the time to empty the bowl. It will sense when the bowl becomes empty and air starts to be drawn in by observing the drop in electrical current.
If, for some reason, the bowl becomes empty but the drain pump keeps running, you can interrupt the process by pressing the Fill button briefly. You will then have to repeat the setup procedure.
If the drain pump stops before the bowl becomes empty, you have to repeat the setup procedure.
If the procedure was successful the parameters will be stored in ROM, the setup mode ends and the FlushRobot is ready for normal use.
If there was a problem, the FlushRobot will enter error mode, and the number of flashes indicate what went wrong.
Configure periodic flush
Enter setup mode as described above. Once the LED lights, do not touch any button but wait for approximately 30 seconds. The LED will then start flashing rapidly.
If you want to enable periodic flush, press the Drain button. If you want to disable periodic flush, press the Fill button.
After this, the new configuration will be stored in ROM, the setup mode ends and the FlushRobot is ready for normal use.
Usage
Use and flush the toilet normally. FlushRobot is not designed to completely take over the flushing process, because - without getting into details - the flush process is different with every use. The FlushRobot assumes that you will manually flush the toilet until the bowl is vacated.
Hose flush cycle
After the manual flush cycle, it is time for FlushRobot to do its job and make sure that the hoses will be flushed.
The LED starts flashing slowly, to indicate that a hose flush cycle is required. You can either double-click the flush button to start the flush cycle right away, but you can also just walk away. After about 5 minutes after the last button press, the FlushRobot assumes that the toilet is vacated and the LED will start flashing rapidly, and ten seconds later the hose flush cycle starts.
The flush cycle starts by sending a vibration signal to the drain pump which results in an audible warning beep. By pressing either the Fill or Drain button the flush cycle will be postponed for another 5 minutes. Once the hose flush cycle has started, you can press the drain button to abort the process.
It will three times fill the bowl with some water and run the drain pump until it senses that the water is gone. This is done to make some "head room" in the lower part of the toilet to make sure there is no dirt left that can dilute the cleaning water in the next step. It will then fill the bowl to the configured maximum level, which will then allow the Flush Robot to run the drain pump long enough to really flush out the hoses and leave them filled with clean water.
Periodic flush
The periodic flush is disabled by default, but you can enable it via the setup mode.
The periodic flush is a brief flush every 4 hours after the last button press. This is intended to keep the water oxygenated to prevent the "rotten egg smell" which results from decaying plankton. The cycle consists of pumping some water in the bowl and pumping it away. No warning beep is given, to keep the whole process as quick and silent as possible.
The periodic flush will halt if the toilet is not used for more than 7 days. This is a safety measure.
Safety
Any pump, especially salt water pumps due to their unlimited water supply, forms a safety risk. If run uncommanded, or when a connected hose fails, it can potentially flood the boat and sink it, leading to loss of property and life.
The following safety features have been built into the FlushRobot:
The FlushRobot senses the voltage on the output terminal of the Fill pump. If it senses an uncommanded voltage for longer than the time to fill the bowl to the configured maximum bowl level, it will start the drain pump, empty the bowl, and repeat this process as long as the Fill pump keeps running. This feature protects against manual overfilling, as well as electrical failures (short circuits to the fill pump) that could result in flooding the boat. This protection disregards the low battery voltage protection, as keeping the boat afloat is more important than keeping the battery healthy. The FlushRobot will keep working until the battery level drops below 5V, at which point the fill pump will soon stop producing any output.
The FlushRobot has a microcontroller with a built in watchdog. If a certain software point is not triggered every 4 seconds, the microprocessor will reset automatically. The most likely culprit would be a lightning strike on or very close to the boat, sending the processor into an undetermined loop. By automatically resetting the processor the FlushRobot will re-enter a safe state with all pumps powered down.
The FlushRobot measures the current to the drain pump. If the current is far below the current measured during the setup, it will assume that the connection to the drain pump is broken and it will enter the error mode. If the current is much more than recorded during the setup, it will assume that the drain pump has seized, is blocked, or has short circuited, and in these cases it will also enter the error mode.
Any switch in the fill pump system, including the internal fill pump switch of the FlushRobot, can fail into the "on"-state, for example after a catastrophic lightning strike or water ingress in the circuit, and result in a runway fill pump. This means that the FlushRobot, like any additional circuitry, forms an additional risk. Then again, the FlushRobot protects against flooding by sensing that something is wrong and it will activate the drain pump in response. It so not only guards against its own switch failing but also against the failure of the mechanical switch of the original control panel. In the end, it can be argued that the FlushRobot is a nett safety enhancement, but it is up to the user to weigh the risks. Catastrophic events like (but not limited to) voltage excursions, lightning strikes and water ingress can have unpredictable results including failures of the built in safety systems.
Regardless of FlushRobot, a live sea water pump circuit and open sea cocks always pose a risk if the boat is left unattended. We recommend the good practice to pull the associated circuit breaker and/or close the sea cock if you leave the boat. After an electrical "event", such as a (nearby) lightning strike, always check that no pumps are runaway.
Troubleshooting
- No activity at all
- Check the power supply (both the minus and the plus) to the FlushRobot.
Error modes
All error modes are fatal. That means that there is no way to exit the error mode, other than powering down the FlushRobot. Error mode is indicated by repeated LED flashes. The number of flashes indicates the type of error:
- One flash
- This is not an error but just an indication that a button press was observed and that FlushRobot is now counting down to perform its hose flush cycle.
- Two flashes
- If this error occurs during setup mode, it indicates that the recorded time to fill the bowl was too short, or could not be detected at all. Rerun the setup mode to try again.
- Three flashes
- If this error occurs during setup mode, it indicates that the recorded time to drain the bowl was longer than the time to fill the bowl. Something might have gone wrong, so rerun the setup procedure. If the error persists, it means that the fill pump is faster than the drain pump, which is a potentially dangerous setup. The FlushRobot is not compatible with such systems. Contact TheFloatingLab with details about your toilet system.
- Four flashes
- The measured current to the drain pump was significantly lower than expected. This might indicate a broken drain pump or connection. For your safety, the FlushRobot went into error mode. If you think the drain pump is ok, it is possible that FlushRobot recorded a too high current during the setup procedure. Rerun the setup procedure to record a new nominal drain pump current.
- Five flashes
- The measured current to the drain pump was significantly higher than expected. This might indicate a seized or blocked drain pump or a short circuit. For your safety, the FlushRobot went into error mode. If you think the drain pump is ok, it is possible that FlushRobot recorded a too low current during the setup procedure or that some bearings have aged . Rerun the setup procedure to record a new nominal drain pump current.