Boiler; Brewing Unit - LAVAZZA LB 4712 Maintenance Manual

Maintenance manual for technical assistance
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1.3.6.1. Boiler

The boiler is constructed of copper sheet (a).
heat exchangers, connected to the brewing unit, are at-
tached to the boiler. Water for coffee brewing is taken di-
rectly from the heat exchanger. during brewing, cold
water is sent inside of the exchanger by the power
pump.
Inside the heat exchanger, cold water and the pre-exi-
sting hot water are mixed, thus obtaining optimal water
temperature for coffee infusion. The water is heated into
the boiler by an electrical heating element immersed in
the water (B).
Manual code 10066846 / Rel. 0.00 / March 2012
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A
B

1.3.6.2. Brewing unit

The brewing unit and the heat exchanger are funda-
mental components to obtain espresso coffee.
Specifically the function of the unit is coffee dispensing.
In this system the brewing unit (1) is heated by a ther-
mosiphon circuit (2) connected to the heat exchanger
(3). The same water is used for coffee brewing, this en-
sure the same temperature for all coffees:
- activation of the solenoid valve and the pump allows
cold water to enter the exchanger (3) via the injector
(4);
- heated water is carried to the unit (1) for brewing from
the exchanger (3);
- the pump allows water pressure to be increased up to
8-9 bars for brewing.
To increase the coffee extraction temperature, remove
the flow reducer (5) or replace it with one of a larger dia-
meter. To decrease the temperature, replace it with one
of a smaller diameter.
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At resting position
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Coffee
dispensing
During dispensing
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