Brew Tank - Bunn AutoPOD Technical Training Manual

Water enters the inlet valve and is regulated by a .175 flow control and enters the bottom of the hot water tank. The
tank will fill with water to refill probe level and will heat to the adjusted temperature, which can be set in programming.
When a user press and holds the momentary hot water button, the air pump will turn on for calibrated period of time
to pressurize the tank while the vent valve closes to deliver a 10 ounce portion of hot water.
Brew Tank Dispense
The brew tank dispense system consists of:
• Inlet valve (.175 flow control)
• Optional booster pump (set at 10psi)
• Flow meter
• Pressure switch
• Air pump

• Brew tank

• Sprayhead assembly
The brew tank is initially filled upon startup and monitored by flow counts from the flow meter. Once the tank has
met its flow count number the machine will begin heating the brew tank. At this point, the incoming brew water will
displace the 200º F water in the brew tank which will maintain a level of water in the tank when commanded by the
portion buttons. The large and small buttons are adjustable by volume and recipe (coffee or tea) in the programming
menus. The volume or portion dispense size is calculated from flow default meter counts. This is why its important
to calibrate the brew flow upon placement of the machine to the actual amount of brew water delivered during the
calibrate flow test. The BUNN default dispense value is 10 ounces during this calibration test. Once the actual flow
®
amount is entered in programming, the machine will automatically adjust the flow count number to achieve a 10
ounce dispense.
During a dispense water enters the inlet valve and is regulated by .175 flow control and enters a booster pump,
(Not all AutoPOD™ units have a booster pump; product number specific), which is capable of 50psi. The pump is
intended for low water pressure applications. With some heavier/finer grind pods that require more pressure to brew,
if the pressure gets below 25-30psi they will brew slower. The pump will boost the incoming water pressure to a high
enough level to brew normally. These pumps can create 50+psi, but the pod will determine the actual brewing pres-
sure.
After the booster pump, water en-
ters the inlet of the flow meter and
pushes the paddle wheel and exits
out the flow meter and connects to
the four way plumbing fitting and
continues onto the bottom fitting of
the brew tank. A pressure switch
connects directly opposite of the
water inlet on the 4 way fitting. The
pressure switch is calibrated to ap-
proximately 40psi. The purpose is
to monitor the pressure during the
coffee brewing process. If pres-
sure should exceed the 40psi in the
brew head assembly, the machine
will abort the brew and display an
error code. After every brew cycle,
the machine will go through a
sequence of running the air pump
longer to empty the sprayhead tube
of any brew water and stop. The
machine will now be ready for the
next brew.
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Bunn-O-Matic Corporation