VKI Technologies Zuma Brewer Operation manual

VKI Publication #N016352 May 2014
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

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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.

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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:Somecomponents 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.