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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, then 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.
Zuma – Adjusting & Handling (N016568)
December 4, 2001
Page 4
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