Delta Mayor D 1 Gr Manual page 46

4. TECHNICAL DESCRIPTION
4.1 working principles
The espresso coffee machine is composed essentially by the following elements:
- Boiler
Main functions are water heating and steam production. It is made in a low lead content copper alloy.
- Distributor group with dedicated thermal tube
The distributor group is the component in which the filter holder is inserted and trough the passage of hot water,
originates infusion phase and beverage distribution. The thermal tube, one for each group, while submerged, allows
heat transfer from the boiler's hot water to the incoming tap water, reaching ideal temperature for coffee extraction
in the minimum amount of time and without causing thermal imbalances in the machine.
- Heating element
It is a tubular resistance that heats water and produces steam inside the boiler.
- Electric pump
This device is used to increase water pressure, usually insufficient when it comes from public water network, until
it reaches 9 bar, ideal for extracting the best espresso.
- Vapour lance
Allows foaming milk trough vapour, essential to make cappuccino, also allows to heat water or punch as well as to
prepare chocolate.
- Water lance
It supplies hot water for preparing hot beverages like infusions.
- Control instruments
Pressure gauge: indicates boiler and pump pressure.
Pressure switch: pressure and heating element control to keep water temperature constant inside the boiler.
Thermostat: works as a safety element, cutting the power to the heat source in the event of overheating.
- Pilot lights
Indication of boiler filling and heating element turning on
- Main switch
It allows three positions "0" position: The machine is turned off, without any electrical supply; "1" position: turns on
all electrical components except the boilers heating element; "2" position: turns on all electrical components including
boilers heating element.
- Cup heater switch
Turns on cup heaters heating element
- Pressure switches
Coffee extraction – Semi-Automatic Model
- Keyboard 5 buttons
Coffee extraction with different doses and start/stop – Automatic Model
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