The rainwater unit combines all the components required for operation in one device, pumps the water from the rainwater storage tank and feeds it under pressure into the rainwater pipe network.

Controls the entire rainwater system, checks the fill level of the storage tank and, if necessary, automatically ensures mains water top up within the wall-mounted unit.

Plug-in version complies with DIN EN 1717 and DIN 1989.
Dimensions of Optima wall-mounted units (mm): W 500 x H 510 x D 315

Scope of delivery

Wall-mounted unit in the house:

  • normal-priming, multistage centrifugal pump
  • Zeta 02 automatic switch, switch-on pressure 1.5 bar with manometer
  • Automatic mains water top up via 9-litre storage tank
  • Cover, wall bracket
  • Labelling set

Submersible pump in the cistern:
  • Provedo VX submersible pressure pump with fixed, vertical float switch, 20 m connection cable, 1" nozzle with non-return valve on the pressure side, 3 m lifting rope and hook screw.
  • Baseplate 22 cm x 22 cm for submersible pressure pump, made of stainless steel
  • Floating suction fine filter made of stainless steel, mesh size 0.3 mm, with 1 m highly flexible suction hose

The installation and operating instructions for this product are provided in German and English only. By purchasing this product, you agree.

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Worldwide shipping


Once your order has been placed, you will receive a confirmation email informing you that our shipping team has received your order. Once your order has been processed, you will receive an email notification with your tracking information. Shipping costs will not be refunded in the event of a return. We ship with:

Parcel shipping Pallet delivery Delivery by forwarding agent Delivery by WISY AG

Uninterrupted water supply

If, in a period of dry weather the Rainwater storage tank should become empty, the system automatically switches to mains water mode, with the float switch in the cistern serving as a sensor .

Up to 97 % more economical in standby

The controls of many rainwater units have a power consumption of up to 15 watts in standby mode , which accounts for most of the energy required for rainwater utilisation. With the efficient ZETA 02 control system, developed in cooperation with the Technical University of Hesse, THM in Giessen the standby consumption is reduced to less than 0.2 watts. This means energy savings of up to 97 %in Standby mode, compared to conventional rainwater units. The ZETA 02 is included as standard in the OPTIMA rainwater units.

Pump logic

OPTIMA 4 and OPTIMA 5 are equipped with two pumps : a submersible pump in the cistern and a centrifugal pump in the rainwater unit. This combination enables a delivery rate of up to 65 litres per minute to the tapping points, even with a supply line length of up to 25 metres between the cistern and the rainwater works. Normally, both pumps work together, but during low rainfall, the pump in the rainwater works takes over operation alone when the top up is active.

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Article number

Optima 4 RW 9924
Optima 5 RW 9925

Technical data

Centrifugal pump in rainwater unit Prism 15/3 Prisma 15/4
Submersible pump in the cistern Provedo VX
Automatic switch Zeta 02
Electrical parameters
Power consumption centrifugal pump 600 W 800 W
Power consumption submersible pump 510 W 510 W
Power consumption stand-by / standby mode < 0,2 W
Mains connection 230 V, 50 Hz, single-phase
Max. Current consumption of entire system 10 A
Mains connection cable rainwater system 1.5 m (3 x 1.0 mm²)
Submersible pump connection cable 20 m (3 x 1.0 mm²)
Protection class against environmental influences
Submersible pump IP 68
Water connections of the rainwater system
Cistern connection 1" outside thread
mains water connection ³/₄" outside thread
Output to consumers 1" outside thread
Water connections of the submersible pump
Suction connection 1" nozzle
Discharge connection 1 ¹/₄" inside thread
Sound pressure level in the house
Rainwater operation 52 dB (A) 57 dB (A)
Mains water mode 63 dB (A)
Pump capacity of entire system
Maximum delivery head (at 20 l/min) 30 m 40 m
Switch-on pressure for the pumps of the rainwater works 1.5 bar
Max. Operating pressure rainwater operation 4.2 bar 5.3 bar
Max. Max. operating pressure mains water operation 3.3 bar 4.4 bar
Max. permissible operating pressure 8 bar
Mains water connection
Min. inlet water pressure 1 bar
Max. inlet water pressure Inlet water pressure 6 bar
Water top up volume (at 3 bar, cross-section ³/₄") approx. 95 l/min
Max. Water temperature 35° C
Volume of intermediate storage tank 9 litres
Wall unit (depth x width x height in mm) 315 x 500 x 510
Scope of delivery
Rainwater system (wall-mounted unit with centrifugal pump, ZETA 02 automatic switch and intermediate storage tank)
Wall bracket
Provedo VX submersible pump with floating fine suction filter and float switch
Baseplate for submersible pump made of stainless steel
Stainless steel fine suction filter with suction hose
Labelling set