Operation
STULZ UltraWater 3-stage reverse osmosis system SUW
© STULZ GmbH, Hamburg
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Note:
For contact to a conductivity monitor (error message to the BMS or acoustic signal if conductivity is
too high), we recommend the STULZ conductivity measuring kit.
9.
OPERATION
The supplied water is conveyed through a prefilter and particles and chlorine are removed from it. The
prefiltered water is pumped through a semipermeable membrane by the pressure pump, and divided into
a pure water flow and a waste water flow. The volume of waste water is adjusted automatically by a flow
restrictor.
If the intake pressure upstream of the device drops (e.g. because the drinking water supply has been cut
off), the inlet valve of the device closes for safety reasons. The intake pressure is monitored by a sensor. If
it falls below the minimum, the system automatically shuts down to protect the booster pump from running
dry, and to prevent water from flowing back into the drinking water mains.
The pure water is stored in a pressure tank. When the tank is full, a tank pressure switch shuts down the
system. External demands (e.g. from the humidifier) causes the pressure inside the device to fall, and the
osmosis water is conveyed out of the tank and runs through the combination afterfilter to the tapping point.
When the tank is approximately just half full, the system switches itself back on.
The membrane is designed in such a way that dissolved minerals (common salt, hardness elements,
nitrates, silicic acid) and organic compounds (solvents, pesticide and drug residues) are retained (pure wa
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ter). To ensure that the membrane does not immediately become clogged, the water containing pollutants
must be diverted before it reaches the membrane (waste water). Therefore, make sure that waste water is
being produced whenever the device is cleaning drinking water.
The pure water quality and throughput of a reverse osmosis system are influenced by several factors.
• The better the quality of the untreated (drinking water), the higher the quality of the pure water.
However, the quality of the tap water can mostly not be influenced.
• The higher the water pipe pressure, the more pure water can be produced, and also with better quality.
The devices of the STULZ UltraWater series are therefore equipped with a booster pump. Excessively
high pressure can damage the membrane.
• The warmer the supply water, the greater the pure water throughput of the reverse osmosis system.
However, the water should not exceed a temperature of +35°C, as otherwise this will adversely affect the
membrane.
The tank must be drained before longer periods of shut down (more than
5 days)!
Never allow the membrane to freeze! It will suffer immediate and irreparable
damage.