Operation with prewarmed water (solar heated)
The continuous-ﬂow heater can only heat prewarmed water
to a max. of 60 °C. If the cold water supply exceeds a tem-
perature of 55 °C, the water will not be warmed any further.
Important: The cold water supply temperature must not be
higher than 55 °C!
If the cold water supply exceeds a temperature of 60 °C, a
circuit breaker will trigger and shut the appliance off. There-
fore, the residential plumbing must be equipped with a ther-
mostatic premixer (e. g. special accessory BZ 45T20) that will
limit the cold water supply temperature to a max. of 55 °C by
appropriately mixing in cold water.
BZ 45U20: for use of the continuous-ﬂow heater
as an under sink appliance
Priority switch (load shedding relay)
for operation with a priority circuit
BZ 45K23: for surface mount installation
BZ 45T20: for installation in the
domestic plumbing when using preheated water