Machine Function And Operations; Main Control Board - Bunn ITCB-DV Technical Training Manual

Component Differences Review
Transformer (Relocated)
The purpose of relocating the transformer to the bottom base is to reduce
the amount of heat being produced under the top hood panel. It's the same
120/12 VAC transformer found in the ITCB-DV HV.
120 VAC Fan
UL requirements state that ambient temperatures under the top hood panel
must not exceed 158°F/70°C. The fan is meant to cool and maintain an oper-
able temperature that is below the UL requirement. The fan is located under
the top panel vents to direct air flow out of the hood and runs
continuously.
Thermistor
The additional thermistor is used to monitor the ambient tempera-
ture under the top hood panel. If temperatures exceed 158°F/70°C,
then a display message will show reading "Check Fan", and all
input/outputs to the control board are shut-down. This allows the
BUNN ITCB HV unit to conform to UL requirements. The thermistor
is located within the liquid level and ground wire harness connector.
If the thermistor ever needs to be replaced, a new liquid level and
ground harness with thermistor will need to be ordered as a service
part replacement.
Note: 1,753 ohm nominal for 70°C/158°F
Relay (ITCB Twin HV)
The additional two relays are used independently to supply voltage to the left or right dilution
valve during a tea brew cycle. The purpose of using relays for the operation of either dilution
valve is to use the existing dc output from the control board that operated the optional funnel
lock valves on a ICB brewer. The relay coils are rated for 120 dc and the supply voltage on the
relay contact is 120 vac for the operation of the dual dilution inlet valve.

Machine Function and Operations

Main Control Board

The main control is the brain of the brewer. In the Digital
Brewer Control (DBC
®
single component that contains all of the programming
software, it interprets all the data it receives from the level
and temperature sensors and activates components to
fulfill those demands. The main control board responds
to the users input through the membrane switch and acti-
vates and controls the brew cycle. The control board can
receive data from Smart Funnels
on the front of the machine.
In a digital brewer the control board takes the place of
the liquid level control board, the timer board, the dilution
timer and the mechanical thermostat. All of these compo-
nents are combined into a single unit.
) system, the control board is the
through a sensing coil
®
Control Board
(Mounted Display)
Gasket
Bezel
Membrane Switch
Bunn-O-Matic Corporation
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