January 2001
5F - 11
Functions - Cooling System
Service Manual Cafitesse 500
Sealing of the Peltier element
●
The development of condensation water on
the cold side in the Peltier element could
lead to corrosion which could drastically
reduce the durability of the element.
As a protection the inner parts of the
elements are coated with a thin layer of
epoxy resin.
Heat sink (3)
●
The heat sink (3) is a ribbed aluminium
body which distributes the heat over an
area big enough to transfer it to the
surrounding air without causing an
accumulation of heat. (Fig. 1)
The typical temperature of the heat sink is
approx. 50 °F above the ambient
temperature.
●
Contamination by dust and grease (especi-
ally in kitchens) can reduce the heat
transferring properties which in turn reduces
the effectivity of the cooling system. In an
extreme case the temperature of the heat
sink (and thus the temperature of the warm
side of the Peltier element) could rise to a
point where it would destroy the Peltier
element.
●
As a protection against dirt the air flow is
sucked into the dispenser through an air
filter. For proper function of the cooling
system it is imperative to clean this filter
regularly.
In spite of the air filter we recommend to
clean the heat sink with a brush during
each service call.
Fan (4)
●
The heat sink (3) is cooled by the air
stream generated by the two fans (4). For
effective cooling it is necessary that the
fans function properly. (Fig. 1)
Temperature regulation cooling system
On/off regulation:
●
Without regulating the temperature of the
cooling compartment the system would
have a constant temperature difference of
78 °F between the surrounding area and
the cooling compartment.
●
The min. admissable temperature for the
concentrate is 35 °F. Therefore, if the
ambient temperature is less than 82 °F the
refrigeration capacity must be interrupted at
times. This is done by the temperature
regulation system. (Temperature sensor/
switching transistor/microprocessor)
●
By means of a temperature sensor (5)
(same type as the temperature sensor in
the boiler) the electronic control determines
the temperature in the cooling compartment.
The cooling remains switched on until the
temperature is too low (35 °F). Then the
cooling is switched off until the temperature
has risen to 40 °F, due to warming from
the surrounding area.
Cooling is interrupted when a beverage is
delivered.
On
On
40 °F
On
Off
35 °F
Off
Off
falling
rising
temperature
temperature
T 1
Cooling
