Saeco GAGGIA VELASCA CMF-OTC, Service Manual

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GAGGIA VELASCA 04 OPERATING LOGIC
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4.3. Single microswitch
Switching on
When the machine is switched on, the gear motor repositions itself as follows:
- It acts on microswitch 1
- The gear motor changes its rotation direction and moves upwards again by approx. 1-2 mm.
- The boiler begins to heat the water for approx. 45 sec., at full power, in order to reach the optimal
temperature. The temperature will then remain at a constant level.
An NTC is used as a temperature sensor; in the event of overheating this reduces boiler element
power consumption.
The electronic system detects the current boiler temperature from the drop in voltage of the sensor
and adjusts it accordingly.
Heating element values and corresponding temperatures : see table.
4.3.1. Temperature sensor (adjustment)
Temp. (°C) R nom (kΩ) ΔR (+/- %)
20 61.465 8.6
50 17.599 5.9
75 7.214 4.1
80 6.121 3.7
85 5.213 3.4
90 4.459 3.1
100 3.3 2.5
125 1.653 3.9
150 0.893 5.1
The gear motor is powered by a direct current mo -
tor that engages with the smaller double toothed
wheel using a worm screw. The unit is mounted on
the axle of the large gear wheel and when a coffee
is requested, it moves from the standby position
to the dispensing position, and then back to the
standby position again.
- Standby position: 1
- Dispensing position: 2
2
1