Douwe Egberts Cafitesse 700, Back Office Manual

Page: 163 / 265

July 2004
5A - 21
Functions - water system
Function: Water level control
• The normal water level is detected by the
normal level electrode (2) and the reference
electrode (4). (Fig. 5)
The minimum and maximum normal level is
achieved by a fixed delay in the software.
• When the normal level sensing fails, the high
level electrode (1) will switch off the inlet
valve and the message "Normal water level
sensor defective" will appear in the display.
When the high level sensor (1) detects water
for the second time, the inlet valve will be
powered by pulses (hammering). (Fig. 5)
Function: Dry boiling protection
• The two longest level electrodes (3, 4)
(reference and low level electrodes) detect
the water minimum level and activate the
security circuit. (Fig. 5)
Function: Water supply
• In the standard version, the inlet valve is
connected to the water mains. This water
supply system must be able to build up a
dynamic pressure of at least 0.8 bar in case
of the removal of 10 liters/min. (limited by
flow restrictor installed in the valve).
In case of too low dynamic pressure, the
boiler might not be refilled fast enough. A
service test device for determining this
dynamic pressure is an available accessory.
The maximum static pressure in the water
mains is not allowed to exceed 10 bar.
An independent water supply system can
also be connected as an accessory.
This system consists of an external water
tank. The tank must be refilled manually. A
double pump is installed in this tank.
(See chapter A.7)
Electrodes:
1 - high level
2 - normal level
3 - low level
4 - reference
1
2
3
4
Fig. 5
Cafitesse 700 - Functions - water system