MNP37M03GBV00 Date: 24-11 Rev. 0
Page 29 of 79
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figure 6.04
1.
Air-break tank
2.
Air-break control card
3.
Water level photocell control system
4.
Water level control safety microswitch
5.
Water intake from mains
6.
Runoff
7.
Open boiler filling connection
8.
Manual air-break discharge
connection
9.
Water supply control floater
6.5. - Pressure boiler.
This is the tank that stores the hot water supplied to the coffee assembly and to the
soluble product mixing beaters. This tank is made of brass with an approximate capacity
of 370 cc. Water is heated using an 1000 W, 220 V heating element (figure 6.05).
The water dose for each product is determined by a set of three solenoid valves set
in series, two of them two-way, with one way for each beater, plus a three-way valve to
feed the coffee assembly. This assembly consists of a brass body with stainless steel
inserts to prevent scale accumulation in the more sensitive areas and the three solenoid
valves with stainless steel control pilots, viton valve seatings and supplied at 220 V. The
three-way solenoid valve is used to supply water to the espresso assembly. This
enables the water left in the Teflon tube after brewing to flow back after the valve
closes. This outlet communicates with the waste bin. The other outlet is directly
connected to the coffee assembly.
Dosage of the water of the various products available is achieved by controlling the
amount of water using a volume counter located behind the air-break. This allows for a
very accurate control of doses, while ensuring that the pressure boiler is always full of
water, as the same amount of water that goes out comes in.
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On the side of the cover there is a sensor for controlling water temperature.
This sensor is programmed to keep water boiler temperature at 90 °C, although this
temperature is programmable. The two covers are kept air-tight with a silicone O-ring.
Should the temperature sensor fail, the boiler has the following control systems:
