The most common installation for a system with supplemental supply unit is illustrated in the figure below. In contrast to the RAINMASTER unit it is important that the overflow is installed above the backwater level since there is a connection by the pipework  between the cistern and basement. Otherwise there is a chance that  water from the sewer could enter the basement if there is a back-wash.  

The INTEWA supplemental supply unit minimizes installation time. An improper iInstallation of the  “air gap“, as per DIN EN1717 is barred. The supplemental supply unit is to be installed above the so-called backwater level. As a general rule, the backwater level is usually above street level.

• The top edge of the funnel must be > 20 cm above the backwater level.
• An additional adequate diameter emergency overflow must be fitted.
• The supplemental supply (1) is to be fed frost-proof via a calming pot into the tank
• A submersible pump delivers the water to the consumption points 

Refill unit with 230 volt float switch:   

• During - installation in the tank this unit should not be connected to the mains power..
• The float switch should be set to the desired height for on/off activation by adjustment of the cable weight.
• After installation, the unhindered movement range of the float switch should be checked.

Refill unit with 24 Volt RAINMASTER D24:

• Setting the refill level see instructions RMD-24