Bunn Fast Cup Series Service & Repair Manual page 45

LOWER FRONT PANEL
Upper Piston & Filter Screen
Purpose: The upper piston travels downward from
Home position, enters and seals brew chamber to
ready the chamber for pressurized brewing. Brew
water enters the bottom of the brew chamber, the
extracted coffee will flow through the upper filter
screen which will exit out the upper piston fitting,
through a dispense valve and exit out the dispense
nozzle.
TEST INSTRUCTION
Note: A compromised upper filter screen can allow
coffee grounds to get into the dispense system and
cause flow restriction.
Areas of Concern:
a) Dispense Nozzle
b) "Y' Fitting/Tube at Dispense Valve inlet
c) Brew Chamber Dispense Solenoid Valve
Enter Service Technician Mode and Select
Service icon
Step 1: Select and enter the Water System tab.
Step 2: Unscrew dispense nozzle and set aside.
Step 3: Touch the Hot Water Bypass Valve button.
Water Flows Out of Outlet - Take apart and
thoroughly clean nozzle and re-install.
No Water Flow Out of Outlet - Continue with
step 4.
Step 4: Obstruction within the water dispense
system. Disconnect or unplug machine
from power and water.
Step 5: Remove left panel to access water system.
Step 6: Disconnect "Y" fitting from Brew Chamber
Dispense Valve (c) and clean obstruction
from fitting and tubes.
Step 7: Remove Brew Chamber Dispense Valve,
take apart and clean. Re-install "Y" fitting,
tube and brew chamber dispense valve.
Step 8: Re-connect machine to power and water.
Step 9: Enter Service Technician mode and select
Service icon.
SERVICE
Piston Outlet
Fitting
Upper Piston
1
45
O-ring
Support Plate
Filter Screen
Bezel
c & 7
b & 6
a
2
3
Continued >