Taylor 337 Service Manual - Refrigeration System
15
Model 337
Controls and Systems
Refrigeration System
The criteria used to cycle off the refrigeration in the
Model 337 are different from those used in other Taylor
equipment. System cycle off depends on both product
viscosity and product temperature. For system cycle
off to occur, the following conditions have to be met:
1. The product viscosity must be greater than the
viscosity set point.
2. The freezing cylinder temperatures must be at
or below the balance temperatures.
3. Both draw switches must be open (draw valves
closed).
If any of the above conditions are not met, the system
will continue to run until they are met.
The balance temperature is a set point that is
automatically set by the control at the first viscosity
cycle off (after the AUTO mode is activated). A balance
temperature is calculated for each freezing cylinder.
The calculation of the balance temperatures depends
also on the temperature of the cylinders at the time that
the freezer is placed in the AUTO mode. If the cylinder
temperature is greater than 25_F (--4_C) or less than
10_F (--12_C), the balance temperature is equal to the
freezing cylinder temperature at first cycle off minus
1_. If the cylinder temperature, at the time the freezer
is placed in the AUTO mode, is between 25_F (--4_C)
and 10_F (--12_C), the balance temperature is equal
to the previous balance temperature.
To control the split during some draw recovery cases,
the relationship between the cylinder temperature and
its balance temperature is used in conjunction with the
viscosity information. During a draw recovery, if the
PWM valves are operating with an even split, the
viscosity condition is met, but one of the cylinders is
above its balance temperature, the PWM split will
change. The cylinder that is above its balance
temperature will be favored with the high split.