Rainwater Unit Multimat

  • Pumping water from the storage tank directly to the appliances
  • Submersible pressure pump:
    Extremely compact and no pump noise indoors
  • Mains water top-up directly into the storage tank
  • ZETA 02 pump controller:
    Less than 0.2 watts in standby mode
  • For long distances or large height differentials
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Regenwasserwerk Multimat mit automatischer Trinkwasser-Nachspeisung


Design and operating principle

The MULTIMAT rainwater unit is designed for use in single-family homes or apartment buildings, but can also operate successfully in small commercial premises. It consists two units: the indoor wall bracket with controller and mains water top-up equipment and the submersible pressure pump with float switch and suction filter in the rainwater storage tank. If one extraction point in the rainwater circuit is opened, the controller detects the pressure drop and switches the pump on. The rainwater is pumped directly from the storage tank to the extraction points. The pressure indicator displays the pressure in the rainwater supply circuit.

Silent and space-saving

Since the pump is located in the storage tank, the indoor installation space required is much smaller than for other systems. There is no audible pump noise. Apart from the sound of flowing water, the indoor system is completely silent.

Multigo 205 or 407 pump

The rugged Multigo submersible pressure pump can build a pressure of almost 5 bar. It is easily capable of pumping water around multi-storey buildings or through long extraction pipes. As part of the MULTIMAT rainwater unit, it is available in two different versions. The small Multigo 205 pump can deliver 80 l/min, while the larger Multigo 407 can pump up to 125 l/min.

Floating coarse suction filter

To ensure that the water supply is of the highest possible quality, a floating suction filter is connected upstream of the submersible pump. It is fitted with a stainless steel filter screen with a mesh size of 1.2 mm. This filter is connected to the pump by a hose and is suspended from a float around 20 cm beneath the water surface. This is the height at which the water is cleanest because heavy particles sink to the tank base, while lighter ones float to the surface.

Unterwasserpumpe für Regenwasser

Mains water top-up

If the rainwater in the storage tank runs out during a prolonged dry spell, the water reserve in the tank is topped up with mains water. A float switch senses the fill level of the tank. If the water level drops below a minimum limit, the solenoid valve for mains water top-up opens and the water in the storage tank is topped up with enough to meet average daily requirements. This system ensures that an adequate water supply is available at all taps. Thanks to the open outlet, it is impossible for rainwater to come into direct contact with the mains water circuit, so ensuring that the system complies with standards laid down by the German Institute for Standardisation.

Siegel für effiziente Steuerung Englisch

Up to 97 % more energy efficient in standby

The control systems of many makes of rainwater unit consume up to 15 watts in standby mode, by day and by night, 365 days of the year. This standby power consumption accounts for a large share of the energy required to operate a rainwater harvesting system. To solve this problem, WISY partnered up with the Mittelhessen University of Applied Sciences to develop the highly efficient ZETA 02 pump controller. This innovative device has reduced standby consumption to below 0.2 watts, a small revolution in its own way. Compared to conventional rainwater units, the ZETA 02 uses 97 % less energy in standby mode. The ZETA 02 is a standard component of the SIGMA rainwater unit.

Technical Data

Equipment MULTIMAT 205 MULTIMAT 407
Submersible pump in storage tank Multigo 205 Multigo 407
Pump controller Zeta 02 Zeta 02
Hydraulic data
Operating pressure 4,8 bar 4,9 bar
Max. delivery rate 80 l/min 125 l/min
Cut-in pressure of rainwater unit 1,5 bar 1,5 bar
Min. cut-out pressure of rainwater unit 2,2 bar 2,2 bar
Maximum starting frequency 20 times per hour 20 times per hour
Pumped media filtered rainwater, drinking water (no sand content) filtered rainwater, drinking water (no sand content)
Maximum immersion depth of submersible pump 20 m 20 m
Electrical data
Power consumption in rainwater operation (max. output / rated output) 1,000 W / 600 W 1,180 W / 750 W
Power consumption in mains water operation (max. output / rated output) 1,008 W / 608 W 1,188 W / 758 W
Power consumption in standby mode < 0,2 W < 0,2 W
Mains connection 230 V, 50 Hz, single phase 230 V, 50 Hz, single phase
Max. power consumption 10 A 10 A
Mains connecting cable for pump controller 1.4 m (3 x 1,0 mm²) with plug 1.4 m (3 x 1,0 mm²) with plug
Connecting cable for submersible pump 20 m (3 x 1 mm²) with plug 20 m (3 x 1 mm²) with plug
Mains connecting cable for solenoid valve 1.5 m (3 x 1,0 mm²) with plug 1.5 m (3 x 1,0 mm²) with plug
Float switch 20 m (3 x 1 mm²), cable head 20 m (3 x 1 mm²), cable head
Degree of protection against environmental influences
Submersible pump and float switch IP 68 IP 68
Water connections of wall bracket equipment
2 x 1“outside thread 2 x 1“ outside thread 2 x 1“ outside thread
Open mains water outlet, inlet ¹/₂“ inside thread ¹/₂“ inside thread
Open mains water outlet, outlet DN 50 DN 50
Water connections of submersible pump
Discharge end 1“ hose nozzle with non-return valve 1“ hose nozzle with non-return valve
Indoor noise emission wall unit
Rainwater operation 0 dB (A) 0 dB (A)
Ambient conditions
Max. water temperature 40° C (104° F) 40° C (104° F)
Wall unit (W x H x D) 310 x 310 x 150 mm 310 x 310 x 150 mm
Submersible pump (diameter x height) 127 mm x 496 mm 127 mm x 511 mm

Item number

MULTIMAT 205 RW 9025
MULTIMAT 407 RW 9047