The Fluid System - Bosch TCA640 Series Repair Instruction

5.5

The fluid system

The pump (c) sucks the water out of the water tank (a) via flow meter
(b). The water flows through the flow meter thereby causing the
impeller inside to rotate. This generates electrical pulses which are
used to determine the actual volume of water required.
The pump generates a pressure of 5 - 8 bar. The water is conveyed
through a reduction angle (d) and pressure hose to the heating
elements. The NTC sensor determines the temperature of the heater
(e).
After the heating element, the fluid system is divided into a pressure
line to solenoid valve (i) and a pressure line to outlet valve (f) and
then on to drainage valve (g) and to the brewing unit. Outlet valve (f)
has an opening pressure of 4 bar and closes off the brewing system
when hot water and steam are being dispensed.
At the end of a brewing cycle, the remaining water is drained from the
brewing unit into the drip tray (h) via drainage valve.
The rest of the system remains full of water.
Warning!
Risk of damage!
The appliance must be emptied if there is a risk of frost
(e.g. on the way to or from customer services). The
heating element or the piping may be damaged if the
water in the fluid system freezes.
58300000120060_ARA_en_c.doc – 18.09.09
a Water tank
b Flow meter
c Pump
d Reduction angle
e Heater
f 4 bar outlet valve
g Drainage valve
h Drip tray
i Solenoid valve
1 Hotwater / steampipe
Coffee outlet
2
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