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VKI Publication #N016352 February 26, 2016
Zuma Brewer
Operation and Service Guide
Contact:
Customer Service – Service à la clientèle
800.567.2951
Technical Support – Soutiens technique
888.854.0207
Zuma Brewer - Operation & Service Guide
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Zuma Brewer - Operation & Service Guide
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Table of Contents
Introduction .............................................................................................................................. 5
Brewers Shipped from VKI .................................................................................................... 5
How the VKI Zuma Brewer Works ........................................................................................... 6
Removing the Brew Chamber .................................................................................................. 7
Installing the Brew Chamber ................................................................................................... 7
Adjusting the Brew Chamber Tension .................................................................................... 8
Tension is Good.................................................................................................................... 8
Tension is Too Low ............................................................................................................... 8
Tension is Too High .............................................................................................................. 9
To adjust the brewer chamber tension: ............................................................................... 10
Brewer Crank Tool .................................................................................................................. 11
Cleaning the Brewer (with VKI Powdered Brewer Cleaner) ................................................. 12
Removing the Brewer Filter Screen ...................................................................................... 13
Zuma Brewer Screens – 3 Types Available ........................................................................ 13
Screen Assembly Extractor Tool ......................................................................................... 13
Removing the Filter Screen ................................................................................................ 14
Installing a Filter Screen ..................................................................................................... 14
Cleaning the Brewer Filter Screen ......................................................................................... 15
Replacing the Brewer Cylinder and Teflon Seal ................................................................... 16
Removing the Brewer Cylinder and Piston .......................................................................... 16
Removing the Old Teflon Seal ............................................................................................ 18
Installing a New Teflon Seal................................................................................................ 18
Installing the Brewer Cylinder and Piston ............................................................................ 19
Replacing the T-Bar & Housing, Crank Arm, Triple Cam, and the Brewer Arms ............... 21
Disassembling the Brewer .................................................................................................. 21
Re-assembling the Brewer .................................................................................................. 24
Zuma Brewer - Operation & Service Guide
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Zuma Brewer - Operation & Service Guide
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Introduction
This document was created to guide you through the procedures for adjusting, handling, and servicing that
are essential for keeping the Zuma brewer operating efficiently and problem-free. Following these
procedures will greatly reduce the risk of damage to the brewer, the brewer drive motor, or other components
in your equipment.
There are certain operating guidelines and preventative maintenance procedures that must be followed to
ensure the Zuma brewer functions properly and efficiently. These guidelines and procedures are outlined
below, and are also detailed in this guide. It is important that you read this guide to familiarize yourself with
this brewer and these procedures. Some of the topics covered in this guide include:
• Handling the Zuma brewer
• Cleaning the brewer and the filter screen
• Proper brew chamber pressure adjustment
• Replacing components that wear over time
• Replacing other critical components
Brewers Shipped from VKI
Whether you receive a Zuma brewer as an individual assembly or incorporated into a VKI machine, it
will be shipped in the closed position with the brew chamber down. This is done to accelerate the
settling effects of the brewer's components - in particular, rubber seals, gaskets and spacers. This, in
turn, reduces the likelihood that a new brewer will require major adjustments shortly after its installation.
Please note, however, that minor adjustments may still be required prior to and/or after installation.
Zuma Brewer - Operation & Service Guide
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How the VKI Zuma Brewer Works
When the cycle is started, the piston starts moving upwards, while the brew chamber moves down
(closing) to create a seal between the bottom of the chamber and the top of the cylinder.
Coffee, and then water, get dispensed into the brew chamber. The piston continues moving
upwards, forcing air through the coffee grounds and water. The agitation created by the forced air
mixes the coffee and water together, starting the extraction process.
Once the piston reaches its highest position, it pauses to allow more contact time between the
coffee grounds and water. This contact time increases the extraction from the coffee grounds.
The piston then starts moving downwards, creating a vacuum in the brewer cylinder. When it is
just above the pour spout area of the cylinder, the piston then pauses. This pause allows the
vacuum created in the cylinder to pull the liquid (brewed coffee) through the coffee grounds and
through the filter screen at the top of the cylinder.
The piston then moves down just below the pour spout area, dispensing brewed coffee into the
user's cup. At the same time, the brew chamber lifts and a rubber wiper moves from the right side
of the chamber, to the left side.
The brew chamber lowers slightly to bring the wiper onto the top surface of the cylinder and filter
screen. The wiper then moves across the top of the cylinder (and filter screen) wiping the used
coffee grounds off the right edge on the cylinder and into a waste container. The brewer then
moves back to the home (starting) position and is ready to repeat the process for the next user.
NOTE: The maximum capacity of this brewer is approximately 325 ml (11 oz.). Do not attempt to exceed
this value as doing so may create flooding/overflow problems with the brewer.
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Removing the Brew Chamber
The brew chamber needs to be removed periodically either for cleaning, or for replacing of the filter screen
that is located directly beneath it. To remove the brew chamber, follow this simple procedure:
1. Lift/open the brew chamber by
either using the "Open
Brewer" function of the
machine, or you can open it
manually by using the brewer
crank tool (see page 11).
Note: When the piston is at
its lowest position, the brew
chamber will be open.
2. Lift the release latch on the
front of the brew chamber to
unlock the chamber ().
3. Pull the brew chamber straight
out towards you ().
Installing the Brew Chamber
The installation of the brew chamber requires some precision. It is critical that the wiper assembly is properly
aligned prior to locking the brew chamber in place. To Install the brew chamber, follow this procedure:
1. With the brewer chamber
open (up), make certain
the two aluminum arms
located directly behind the
cylinder () are spread
open (one to the left and
the other to the right).
2. Make certain the wiper
assembly on the brew
chamber is centered on the
chamber (). If it is not,
simply slide it so that it is
centered.
3. Align the protruding guides on each side of the brew chamber with the tracks (slots) on each side
of the h-frame (), and slide the brew chamber all the way back until it locks in place. To make
certain it is locked, try pulling the brew chamber out (without using the release latch).
4. Close the brew chamber by either using the "Open Brewer" function of the machine, or you can
close it manually by using the brewer crank tool (see page 11).
Caution: Failure to properly align the brew chamber during installation may result in excessive
brewer damage.
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Adjusting the Brew Chamber Tension
Proper brew chamber tension is critical for the operation of the Zuma brewer. If the tension is too high, the
added pressure can result in severe damage to brewer components and the drive motor. If too low, it will
result in leaks and improper cleaning of the spent coffee grounds.
Tension is Good
The illustration below shows the ideal tension for the brew chamber. As the wiper is moving across the
top of the filter screen, it lightly brushes the surface of the screen
Tension is Too Low
The illustration below shows too little tension for the brew chamber. As the wiper is moving across the top
of the filter screen, it does not come into contact with the screen to remove the spent grounds.
Signs that tension is too low:
• Liquid is leaking from between the top of the brewer cylinder and the bottom of the brew chamber
• The wiper is not removing all of the spent grounds from the top of the filter screen
• The wiper appears to be 'floating' over the filter screen and does not come into contact with the
filter screen itself
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Tension is Too High
The illustration below shows too much tension for the brew chamber. As the wiper is moving across the
top of the filter screen, it bends or folds over.
Signs that tension is too high:
• The operation of the brewer or brewer drive motor sounds very loud
• The brew chamber makes a loud snapping sound when it opens
• The wiper appears to get crushed when wiping the coffee grounds
• Coffee grounds are flung towards the right side of the machine
• As the wiper moves to the left, it catches the top of the coffee paddie
To Recap:
Tension is too low Ideal tension Tension is too high
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To adjust the brewer chamber tension:
Note: Some components are not shown to simplify the illustration
1. Make sure the brew chamber is open (up).
2. Push down on the H-frame (1).
3. Lift the T-bar out of its recession on the H-frame and turn it so that it is out of the way (2).
4. Adjust the brew chamber tension.
TO INCREASE TENSION:
a) Add one shim into the recession and replace the T-bar.
b) Test the operation of the brewer.
c) If more tension is required, remove the shims that were added and perform one full clockwise
rotation on the T-bar. One rotation of the T-bar is equivalent to adding two shims.
d) Test the operation of the brewer.
e) If more tension is required, repeat the above steps until the tension is correct.
TO DECREASE TENSION:
a) Remove one shim into the recession and replace the T-bar.
b) Test the operation of the brewer.
c) If less tension is required, remove the shims that were added (above) and perform one full
counter-clockwise rotation on the T-bar. One rotation of the T-bar is equivalent to
removing two shims.
d) Test the operation of the brewer.
e) If less tension is required, repeat the above steps until the tension is correct.
NOTE: If more than two extra shims are required, remove the extra shims and rotate the T-bar
accordingly instead. There should never be more than two extra full shims in the recession and the
original shim that was in the brewer should never be removed.
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Brewer Crank Tool
The brewer crank tool (VKI p/n - A110253) is a handy tool to simplify the servicing of every type of brewer
that VKI manufactures, including the Zuma Brewer.
By connecting the coupling on the crank tool to the coupling at the rear of the brewer, you can easily turn the
brewer to the position required for servicing.
WARNING: Never, under any circumstances, turn the Zuma brewer in a backwards direction - doing
so will severely damage the brewer assembly.
Brewer Crank Tool
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Cleaning the Brewer (with VKI Powdered Brewer Cleaner)
To properly clean and de-stain the brewer without damaging the components, rinse the brewer using only a
VKI approved brewer cleaner (VKI p/n - M019610). The use of any other types of cleaning agents may cause
damage to plastic and rubber components on the brewer.
CAUTION: Do not soak plastic parts in brewer cleaner for prolonged periods of time as doing so will
make the plastic brittle and easy to damage. The maximum soak time is 30 minutes.
The following procedure outlines the "Brewer Rinse" cycle function that is available on all VKI equipment.
On non-VKI equipment, follow the manufacturer's recommended brewer rinsing instructions.
1. Place a leak-proof container underneath the brewer pour spout area.
2. Add VKI approved brewer cleaner to the brew chamber.
3. Press the "Rinse Cycle" button on the control panel inside the front door.
4. Press the "Coffee Rinse" button on the front selection panel to begin the cycle.
a) The piston will move to the top of the cylinder, water will pour in, and the brewer will pause for
about 5 minutes. During this time, the cleaner breaks down all of the oils and stains that have
accumulated in the brewer.
b) After the 5 minutes have elapsed, the brewer will cycle, dumping the cleaner into the waste
container in the process. The brewer will then automatically cycle water seven consecutive
times to rinse the cleaner from the brewer. After the rinse cycle is completed, the brewer will
stop and the coffee maker will automatically exit the rinse mode.
c) After the rinse cycle is complete, brew a few cups of coffee to re-lubricate the brewer.
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Removing the Brewer Filter Screen
The Zuma brewer is equipped with a filter screen than can be easily removed when it requires cleaning or
replacing. The standard Zuma brewer uses a 40 micron brewer screen, however optional 51 micron or a
stainless steel screen (approximately 37 micron) are also available from VKI.
Zuma Brewer Screens – 3 Types Available
VKI currently offers 3 types of filter screens for the Zuma brewer. The following describes each of the
screens (identified by their VKI part number):
K310306S - a polyester screen that filters out particles that are larger than 40 microns. This is
the standard Zuma brewer screen and is ideal for the majority of installations.
K310032S - a polyester screen that filters out particles that are larger than 51 microns. This
screen may last longer before it requires cleaning, however, it does allow larger particles
into the cup, and depending on the grind used, may leave a little sediment at the bottom of
the cup.
K310297S – a stainless steel screen that filters out particles that are larger than 37 microns.
Lime/calcium will build up on this screen more quickly because of the very fine stainless steel
mesh. As a result, this screen requires more frequent cleaning than the other two screens
offered. In some cases (particularly where slack develops on the screen and the brew
chamber is adjusted too tightly), the screen will fold slightly as the wiper moves across it. After
repeated use, this may cause cracks or tears in the mesh due to metal fatigue.
Screen Assembly Extractor Tool
The screen assembly on the Zuma brewer can be easily removed for cleaning or replacement by
using this special screen extraction tool (VKI p/n - K023029SS). It is inserted through the brewer
spout and is used to push the screen out of the top of the brewer cylinder. Using any other type of
tool to remove the filter screen may damage the brewer, and is therefore not recommended.
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Removing the Filter Screen
To remove the filter screen from the Zuma brewer:
1. With the brewer in the open position and the piston at its lowest point, remove the brew
chamber.
2. Insert the screen extractor tool through the pour spout ()and into the brewer cylinder.
3. Align the tip of the screen extractor with the rounded area at the rear of the filter screen ()
and push the screen upwards to unlock it.
4. Remove the filter screen assembly ().
Installing a Filter Screen
1. The filter screen has a rounded protrusion on one
side of the plastic frame to indicate which side is the
rear of the screen. Align this rounded protrusion with
the rounded notch at the top rear of the cylinder.
2. Once aligned, push the screen into the recession on
the top of the brewer cylinder until it locks in place
(there are small clips of both sides of the screen
which physically lock the screen to the cylinder).
3. At this point, the screen should be flush with the top
of the cylinder.
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Cleaning the Brewer Filter Screen
Over time, coffee oils and fine grounds (the size of dust particles), as well as minerals in the water will
accumulate on the brewer filter screen. This accumulation will decrease the porosity of the screen, making it
difficult for the liquid to flow through, resulting in brewer flooding. The Zuma brewer screen must be kept
clean to prevent this from occurring.
Soak the filter screen(s) in a solution of water and dishwashing liquid for a few minutes to start
breaking down the coffee oils on the screen(s).
Rinse the filter screen(s) thoroughly with fresh warm water.
Soak the filter screen(s) in a non-diluted solution of VKI-approved Block Whitener (VKI p/n -
M039033S) overnight - approximately 8-12 hours.
Under full tap pressure, rinse the filter screen(s) thoroughly over their entire surface with fresh
warm water. Ensure that water passes through the filter with little resistance. Once done, allow
the screen(s) to dry and store them in their box until they are needed.
WARNINGS:
Follow all of the manufacturer's safety instructions found on the product label.
Never mix different types of cleaners together - this can be extremely dangerous.
Do not use products other than the VKI-approved cleaners. Thorough testing was performed using
these approved cleaners, ensuring that they are non-toxic and that they do not damage the brewer.
NOTES:
• Several screens can be soaked at the same time when cleaning them.
• Used Block Whitener can be stored and re-used several times before it needs to be discarded. When
its cleaning action decreases and the screens do not become as white, discard the used Block
Whitener (in accordance with local regulations).
• Clean screens should be stored in their original protective packaging.
• Screens that have become loose from their frame, or screens that are torn should be discarded and
must never re-used. Torn filter screens will allow coffee grounds to get into the brewer cylinder, which
in turn will score the cylinder walls and the Teflon seal, resulting in loss of vacuum. When this occurs,
the brewer cylinder and the Teflon seal will both need to be replaced.
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Replacing the Brewer Cylinder and Teflon Seal
The Zuma brewer creates a vacuum that pulls hot water through the coffee grounds and the filter screen, and
into the brewer cylinder. The brewer pauses prior to dispensing the brewed coffee to allow this vacuum to
pull all of the liquid into the cylinder. After several thousand cycles, the brewer cylinder and/or the Teflon seal
will become worn and scored. When this scoring gets severe, air will enter the brewer cylinder from between
the Teflon seal and the cylinder wall, resulting in a loss of vacuum. In many cases, you will actually be able to
see these air bubbles during the brew cycle. When a vacuum loss occurs, the brewer cylinder and Teflon
seal will both need to be replaced.
Removing the Brewer Cylinder and Piston
1. Remove the brewer from the machine, and then remove the filter screen and the brew chamber from
the brewer.
2. Remove the c-clip at the rear of the crank arm (), and then remove the crank arm pin (). This
frees the piston rod from the crank arm.
3. Remove the four screws and washers (two on each side) that secure the brewer cylinder to the
brewer mainframe. The screws go through the brewer mainframe and fasten to a metal cylinder plate,
which will fall out from the mainframe when the screws are removed.
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4. Once the screws are removed, lift the cylinder up until it clears the two guide posts on the mainframe
and pull it towards you to remove it.
5. Pull down the piston to remove this assembly from the brewer cylinder. At this point, the old brewer
cylinder can be discarded (but not the piston assembly).
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Removing the Old Teflon Seal
Remove the four screws at the top of the piston assembly.
Remove the stainless steel top plate from the assembly.
Remove the old Teflon seal. It may be necessary to twist the seal or rock it back and forth until it
clears the large rubber piston ring. Once removed, discard the old Teflon seal.
Remove the four old o-rings. These o-rings cannot be re-used and must be discarded - you must
use four new o-rings when replacing the Teflon seal.
Installing a New Teflon Seal
Add a drop of Lubri-film around the perimeter of each of the holes on the top of the piston, and
slightly spread it around.
Align and place four new o-rings over the four holes on top of the piston.
The Lubri-film that was added in the first step will temporarily hold these o-rings in place.
Insert a toothpick through the center of the o-ring and into each of the screw holes on top of the
piston. The toothpicks will hold the o-rings in place and act as a guide for the Teflon seal.
Replacement Teflon seals are shipped inside a thick cardboard sleeve. Do not remove them
from this protective sleeve until they are needed. To remove the seal from the cardboard
sleeve, simply slide the seal out of the sleeve.
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Align the four holes on the new Teflon seal with the toothpicks inserted in step #4 and slide the
seal down over the piston. Make certain the four holes on the Teflon seal and the four holes (and
o-rings) on the piston are properly aligned before proceeding.
After verifying proper alignment, remove the toothpicks.
Place the stainless steel top plate over the newly installed Teflon seal and make certain the holes
on the top plate align with the holes on top of the piston.
Secure the stainless steel top plate in place using the four screws that were initially removed.
The replacement of the Teflon seal is now complete and it is ready to be inserted into the new
brewer cylinder.
Installing the Brewer Cylinder and Piston
1. Slide the piston assembly into the bottom of the cylinder. Make sure the hole at the bottom of the
piston rod is pointing perfectly forward () - in the same direction as the brewer pour spout.
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2. Install the rear of the cylinder onto the two guide posts on the mainframe.
3. Slide the cylinder plate into the brewer mainframe (the flat side of cylinder plate must be up against
the mainframe). Secure the piston and cylinder assembly to the mainframe of the brewer using four
screws (two on each side). Do not forget to install the two washers that are used with each of the four
screws ().
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