VKI Technologies CAFFÈ MIO Operation & Service Manual page 28

B r e w e r A d j u s t m e n t s
Zuma Brewer – Brew Chamber Tension Adjustment
BREWER TENSION IS TOO LOOSE
Figure 1 As the wiper moves across the top of the cylinder, it does not make contact with the filter
screen. This will leave a layer of coffee grounds on the screen. A brewer adjusted this way may
also leak when the brew chamber is closed. If the leak is severe enough, it can result in a loss
of vacuum and possible brewer flooding on larger cup sizes.
Figure 2 Because the wiper is not making proper contact with the top of the cylinder and filter screen,
there is very little or no bend on it. In some cases, this may result in a layer of coffee grounds
remaining on the surface of the screen.
BREWER TENSION IS PROPERLY ADJUSTED
Figure 3 When a Zuma brewer is properly adjusted, the wiper will gently slide across the top of the
cylinder, cleaning the surface of the filter screen. A slight deformation of the wiper can be seen
as it moves across the top of the cylinder and filter screen.
Figure 4 As the wiper moves to the right side, the used coffee grounds will be transported to the waste
container. The coffee grounds will gently drop off the right-most edge of the brewer, directly
into the waste container. The filter screen will be clean of coffee grounds.
BREWER TENSION IS TOO TIGHT *
Figure 5*
When the brew chamber is too tight, the wiper begins to stretch and becomes noticeably
deformed. If you look carefully at the photo, you will notice the rippling effect this has at the
bottom of the wiper. The brewer is under extreme pressure at this point and the sound of the
brewer motor may change to indicate that there is a larger load on it. Permanent damage to the
wiper may also result.
Figure 6* As the wiper moves across the top of the cylinder and filter screen, there will be a very pronounced
bend on it. When it passes over the right-most edge of the brewer cylinder, and the pressure gets
released from the wiper, coffee grounds will be flung towards the right wall of the machine. After only a
few cycles, heavy grounds accumulation can be seen around the waste container and on the right
wall of the unit.
Throughout the complete cycle, the bearing on the wiper arm in under extreme pressure, causing
the complete arm assembly to twist. The vertical rod is also under extreme pressure when the
brew chamber closes. At this point, there is a very high risk of damage to both of these
components. The bearing on the wipe arm will eventually break or snap off, and the pressure
being exerted on the vertical rod will stress the plastic vertical rod housing causing it to initially
crack, and break.
*Please note the Zuma brewer used in Figure 5 and Figure 6 was only slightly overtightened.
If the tension is higher than that used in the example, damage to the brewer components will
occur much quicker and will be more severe.
The following signs are an indication that the tension on the Zuma Brewer may be too tight:
The wiper has a pronounced bend as it passes over the top of the brewer cylinder and filter screen.
•
The wiper carriage looks like it is getting crushed between the brew chamber and the top of
•
the brewer cylinder.
• The motor sounds like it is straining due to a heavy load.
The wiper is hitting the top of the coffee paddy as it passes over it (while moving towards
•
the left side).
Heavy coffee grounds accumulation around the waste container and on the right wall of the machine.
CAFFÈ MIO – OPERATION AND SERVICE
S E C T I O N 3 - M A I N T E N A N C E
Page 28 of 110