Küppersbusch EDG 6600.0, Service Manual

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28 H3-72-01
For internal use only
5. EDG / EKDG appliance components
5.1 Limestone sensor
Limestone sensor and heat protection NTC 25°C/10 kW
Heater installed Heater with limestone Heater dismounted
The amount of scaling is determined as two measured variables, namely the temperature of the heating
spiral and the conductance of the level sensor. Scaling on the tubular heating element of the evaporator
increases the readings taken on the heating spiral temperature sensor. Scaling is tolerated up to a
maximum degree with some difference above the boiling temperature of the water. Until the clear text
display gives an indication the permissible maximum degree of scaling must have been exceeded for
some time (5 times or approx. 200 operating hours).
5.2 Level sensor (point gauge)
Scaling, initially primarily at the top of the level sensor, lowers the gauged conductance level of the water.
Scaling is tolerated up to a maximum degree of conductance. Until the clear text display gives an
indication, the permissible maximum degree of scaling must have been exceeded for some time (5 times
or approx. 200 operating hours).
If one of the measured variables exceeds the maximum permissible reading, the clear text display will
indicate “descale”.
Once the indication has appeared the appliance can continue to operate with steam. However, the effect
of the evaporator is minimized when scaling increases.
Since soft water or a domestic descaling device may result in the limestone sensor not actuating, after
a certain number of hours of operation and for reasons of hygiene the clear text display will require the
user to descale the system.
In order to be able to recognise the water level in the evaporator by means of the level sensor, the
average result of 80 readings during a period of 2 sec. (software) is deducted.