How To Save Energy; Power Limit; Operation With Solar Systems; Venting After Maintenance Work - German pool DEX Operating Instructions Manual

13. How to use

Power limit

Unit provides no output

How to save energy

Set the exact temperature you need on the appliance and open the hot water tap. Once
you feel that the water is too hot, do not add any cold water and, instead, enter a lower
temperature on the appliance. If you were to add cold water, the water already heated
would cool down again and valuable energy would be wasted. Moreover, the cold water
added in the tap is not covered by the control range of the electronic circuitry, with the
result that temperature constancy is no longer guaranteed.
Power limit
If the full output of the instantaneous water heater DEX does not suffice to heat the
tapped quantity of water, this will be indicated by the LCD decimal point (e.g. when
opening several taps at once). When you reduce the hot water flow rate, the LCD point
stops indicating because the output of the appliance is again sufficient to reach the set
temperature.
You can use the full output to fill a bathtub, for instance.

Operation with solar systems

When operating with solar systems, e.g. an automatic mixing tap must ensure that the
inlet temperature does not exceed 70 °C.
If the inlet temperature is too high as the result of the above reason, the flashing deci-
mal point of the digital display indicates that the unit is not providing any output.

Venting after maintenance work

The instantaneous water heater DEX features an automatic air bubble protection to
prevent it from inadvertently running dry. Nevertheless, the appliance must be vented
before using it for the first time. Each time the appliance is emptied (e.g. after work on
the plumbing system, if there is a risk of frost or following repair work), the appliance
must be re-vented before it is used again.
1. Disconnect the instantaneous water heater from the mains by disactivating the fuses.
2. Unscrew the jet regulator on the outlet fitting and open the cold water tap valve to
rinse out the water pipe and avoid contaminating the appliance or the jet regulator.
3. Open and close the hot water tap until no more air emerges from the pipe and all air
has been eliminated from the water heater.
4. Only then should you re-connect the power supply to the instantaneous water heater
and screw the jet regulator back in.
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