Chapter 3 Functional descriptions
58 SMSO-2-02.03- 15.07.03
3.2.18 Steam generator
The steam generator produces the steam used to heat and
foam milk drinks or for the quick cup warmer – an extra op-
tional feature. The comparatively low volumes and the high
heating performance guarantee short heating times yet with
sufficient steam to be able to prepare a product with steam at
any moment.
Function
Steam generators are made from stainless steel. The heater
and the threaded connectors to the supply pipe, the steam
pipe, the temperature sensor and the level probe are welded
at the top. Every steam generator is subjected to a compre-
hensive quality control procedure immediately after it has
been manufactured. The test certificate is a component of the
steam generator and must be kept available throughout the
entire service life of such devices. All checks and service work
must be entered onto the test certificate.
The steam generator is filled with water to approximately half
full. If the water level reaches the level probe the feed valve
closes. In this way there is sufficient room above the level of
water for steam to form. A heating spiral is accommodated in
the lower third of the container. It is connected to the power
relay via two safety thermostats. One of these safety thermo-
stats is located between the two flanges on the heater spiral.
The second is located above the heater spiral and ensures a
reliable temperature transfer even when the steam generator
has heavy calcium deposits.
The feed water is fed through the feed pipe into the lower part
of the steam generator, so that the steam in the lower half is
not cooled by the turbulent effect of filling. The water level in
the steam generator goes down during a steam emission. The
signal from the level probe to the unit control system is
stopped, causing the feed valve to open and water to flow into
the steam generator.
Over-temperature protection: (see “instant heater”).
Steam generator
1 Container (stainless steel)
2 Heater
3 Safety thermostat
4 Feed pipe
5 Water
6 Steam
7 Steam pipe
8 Temperature sensor
9 Level probe
Technical data
Volume: 0.8 l
Operating pressure 2.8 bar / max 12 bar
Heater rating: 3.0 kW
Voltage/current: 230 V AC, 13.0 A
Winding resistance: 15.1 Ω (230 V; at 20 °C)
Operating temperature: 130 °C
Max. over-temperature: 192 °C
Heating time: 10°-->130°C: < 2 Min.
Maintenance
Most frequent faults
Calcium deposits: long heating time
Check
see “instant heater”
Service intervals
After every 45,000 coffee servings or after 12 months of op-
eration check the following:
(All checks must be entered into the inspection report).
Water tightness: Traces of calcium at the welded seam or
at the connections to the heater.
Calcified on the interior: heavy calcium deposits on the
heating spirals
Check supply pipe for seal and calcium deposits.
After 36 months of operation, replace:
the complete steam generator (production date to
12.2000)
After 60 months of operation, replace:
the complete steam generator (production date starting
01.2001)
Drawing symbol
Illustration
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