zuma brewer operation and service guide

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


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


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.


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.


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.


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


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


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.


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


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.


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.


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.


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.


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.


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).


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.


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.


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 ().


4. Insert the crank arm pin through the front of the piston rod and through the crank arm (). It may be necessary to raise or lower the piston in the cylinder to properly align the two. Secure it in place by inserting a c-clip on the pin at the rear of the crank arm ().

5. Install a filter screen onto the top of the new brewer cylinder.

6. Install the brew chamber.

7. Install the brewer into a machine and brew several cups of coffee through it. The coffee oils will lubricate the new cylinder's walls and the new Teflon seal.

Replacing the T-Bar & Housing, Crank Arm, Triple Cam, and the Brewer Arms The following procedure will guide you through the steps required to remove the T-bar (and its housing), the crank arm, the triple cam, and the two wiper arms. As these components are all mechanically linked together, they will all be removed in this procedure. Should you need to replace only one of these components, follow this procedure until the point where that particular component can be removed and replaced.

Disassembling the Brewer

1. With the brewer in the open position, remove the brew chamber (detailed instructions are found on page 7).

2. Press down on the H-Frame and turn the T-bar counter-clockwise until it can be removed from its housing. This may require 20-30 full turns.

NOTE: At this point in the procedure, the T-bar can be completely removed and replaced.


3. Remove the coupling pin at the back of the brewer. This pin is tapered and press-fit into the shaft - tap the longer end of the pin with a hammer until it pops out of the shaft (). Once the pin is out, remove the c-clip securing the crank arm shaft to the mainframe ().

4. 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.

5. Move the piston rod away from the front of the crank arm (). Place the brewer on the table with the

cylinder down and gently tap the crank arm shaft with a hammer () to unlock it from the triple cam - these two components are press-fit together


6. Flip the brewer over (cylinder up) and pull the T-bar housing until the housing and the triple cam can be removed. It may be necessary to move the components back and forth to release them.

NOTE: At this point in the procedure, the T-bar housing, crank arm, crank arm bearing and triple cam can be completely removed.

7. If the brewer was making a load 'groaning' or 'squeaking' sound during operation, the crank arm

bearing should be replaced. Remove the old bearing by lifting it out of the brewer mainframe and then insert a new bearing into the mainframe.

8. To remove the two brewer arms (the 'wipe' and 'unwipe' arms), remove the two c-clips securing the arm pins to the mainframe (), and then remove the two pins at the rear of the brewer (). It may be necessary to push them from the front of the brewer through to the rear.


9. Pull the two arms and the large spring connected to the arms out through the bottom of the mainframe.

NOTE: At this point in the procedure, the two arms can be completely removed.

Re-assembling the Brewer

1. Install the spring onto both of the brewer arms - note that the each end of the spring must be hooked to each arm, as illustrated. With the spring in place, slide the spring and arm assembly into the mainframe through the bottom of the brewer (the spring must be facing towards the front of the brewer).


2. Move the spring and arm assembly up against the front inner wall of the mainframe () and insert the two arm pins through the rear of the mainframe and through the holes in each arm (). At this point, the spring should now be sandwiched in between the arms and the wall of the mainframe. At the front of the mainframe, insert a c-clip into each of the arm pins to secure the pins (and arms) in place ().

At this point in the procedure, the brewer arm replacement is complete. 3. The next part of the procedure is to replace the triple cam and T-bar housing. Even if you were only

replacing one of the two, both of these components need to be removed.

Partially insert the bottom of the triple cam into the opening in the T-bar housing. While keeping the triple cam angled towards the top of the brewer, slide the triple cam and housing into the brewer mainframe. You need to get the top of the triple cam resting inside the opening for the crank arm on the mainframe (), while the bottom is inside the opening in the T-bar housing ().


4. Insert the crank arm shaft through the opening in the front of the brewer, and through the triple cam and T-bar housing. Please note that the crank arm needs to properly couple with the triple cam. To do so, you must align the coupling protrusion on the triple cam () with the coupling recession on the crank arm ().

5. Once you are certain that the crank arm and triple cam are properly aligned, place a center punch in the center of the crank arm shaft (on the side with the plastic crank arm), and give it one or two taps. If the two are properly aligned, the crank arm will easily couple with the triple cam.


6. On the other side of the brewer, secure the crank arm to the brewer mainframe using the c-clip that was removed earlier in this procedure.

7. Insert the crank arm pin through the front of the piston rod and through the crank arm (). It may be necessary to raise or lower the piston in the cylinder to properly align the two. Secure it in place by inserting a c-clip on the pin at the rear of the crank arm ().

8. Insert the drive pin into the crank arm shaft at the rear of the brewer. Note that the pin is tapered (one end is thicker than the other due to three splits added along the pin's sides). Insert the thinner end (without the splits) into the crank arm shaft, and then tap it a couple of times with a hammer to wedge (press-fit) the pin in place.


9. While pressing down on the H-frame, insert the T-bar from the top of the brewer down into the threaded section of the T-bar housing, and turn the T-bar approximately 20 turns clockwise. Once done, install the T-bar into its recession on top of the H-frame.

NOTE: You have now successfully re-assembled the Zuma brewer, however, the brewer will not function properly in its current state. You must now re-adjust the brewer chamber's tension. The procedure for adjusting the brewer tension is outlined on page 8.

zuma brewer operation and service guide

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