Operating manual for melting and
tempering machines, type 2T70 & 2T130
Version 2019-1
8
Operating instructions
The temperatures given in the following sections may be varied according to the type of
chocolate being used. However, we recommend that these temperatures are used in the
beginning until the machine has been through the tempering program several times and the ope-
ration procedures are familiar for the operator.
Afterwards when “fine-tuning” takes place, then be adviced by the chocolate supplier the exact
temperatures for melting, cooling and re-heating for the specific used chocolate.
Set-points
The tempering process is controlled by the thermostats. Once a sensor registers the temperature
of the chocolate is equal to a set point, the thermostat reacts accordingly, and the supply of
power to the heating elements starts or stops – or – the supply of cooling water starts or stops.
From a control system point of view, it is an on / off process. However, the actual temperature
of the chocolate will not change instantly as the change takes place in the thermostat. There will
be a time delay.
If the cooling temperature is set at 28
0
C, then the water supply will be stopped when the sensor
placed in the middle of the vessel register a chocolate temperature of 28
0
C. The water in the
water jacket is still much colder than 28
0
C. The entire vessel will still be cooled furthermore,
before the water in the water jacket and the chocolate in the vessel have a uniform temperature.
Depending of the temperature of the cooling water, this “delayed” cooling may be as much as
1,0 to 3,0-degree C.
In practise it means that if cooling temperature of 28
0
C is needed, then the thermostat is, as a
start, set at e.g. 30
0
C. When the chocolate temperature gets close to 30
0
C, watch the display at
the cooling thermostat. Note the lowest temperature during the entire cooling process. The
difference between this temperature and the set point has to be kept in mind for further
adjustment of the cooling set point. Example:
·
If the lowest temperature turns out to be 27,5
0
C, that is, 0,5
0
C too low, then the set
point is increased by 0,5
0
C to 30,5
0
C. Next time the actual cooling temperature will be
28
0
C.
·
If the lowest temperature turns out to be 28,3
0
C, that is, 0,3
0
C too high, then the set
point is decreased by 0,3
0
C to 29,7
0
C. Next time the actual cooling temperature will be
28
0
C.
The colder the cooling water is, the higher the difference will be. Please have in mind, that if the
temperature of the cooling water may varies (summer / winter) it may affect the tempering
process slightly.
As the pressure and temperature of the water varies, as well as type and quality of chocolate,
there is no predetemined standard settings. It is a “try and error” procedure. Please focus on one
temperature level at the time and make a gradual change of e.g. 0,3-0,5 degree at the time.
If the re-heating temperature is set at 31
0
C, for the same reason, the temperature may for a short
period of time be 0,5-degree C higher that the set point – but the temperature will stabilize at the
