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Blower
The blower produces a forced air flow of 500 cfm, with an air change every two seconds. This forced convection moves energy
from the container surface to the air. The resulting air circulation moves the energy to the evaporator coil, which then moves to
the evaporator and achieves equilibrium. Conventional freezers rely on natural convection, which is efficient but easily disrupted
when the door is opened. In comparison, forced convection enables temperatures to reach equilibrium faster, even after the door
is opened and shut.
Control System
The controller display provides access to the human-machine interface (HMI) and enables approved users to adjust the
temperature control set point between -20°C to -80°C or +2°C to +8°C. All functions and set points can be accessed on either
of the HMIs located on each of the exterior doors. The displays are synchronized; therefore, any adjustments or set points
programmed on one display will be synchronized automatically on the other. Some parameters, such as the defrost cycle time,
are independently set for each refrigeration system including:
Defrost Cycle Time
Defrost Maximum Time
Defrost End Temp
Single Sided/Double Sided selection
Ignore Door Switch
Calibration Interval/Maintenance Interval
Off/Auto control selection
Alarm Log
Clock Set
Components
Control components include:
Circulation Blower
Main Controller
RTD (resistance temperature detector) Temperature Sensors
Solid State Relay
Miscellaneous/Other Hardware
User Access
The ULC Series is delivered with factory default settings. FARRAR™ recommends proper access control to each user with an
assigned username provided by the facility administrator or operator. If a user does not have sufficient privilege or access
control, then no set points or values can be changed within each of the Liquid Crystal Display (LCD) display controllers; instead,
a warning acknowledgment will display.
Each LCD display will offer a view-only mode to a non-authorized user. A username and password will be assigned and
programmed by the facility administrator. The username and password should be maintained and controlled according to
company protocols.
Automatic Functions
The ULC Series controllers are designed to properly maintain the temperature set point and initiate an automatic defrost of the
evaporator coil for each refrigeration system. During the defrost period, the system blower will be turned off in a manner specific
to the refrigeration system (system A or system B), and defrost mode will activate. The secondary refrigeration system will
operate, and its blower will be energized to maintain the proper temperature set point within the chamber. Defrost cycles are
factory programmed to be enabled every 24 hours. However, the defrost cycles can be modified by the end user to occur every
2 to 168 hours, depending on the following: ambient moisture, frequency of door openings, and/or warm product being placed
inside the ULC Series. FARRAR's technical support team can assist users with any questions related to controller adjustments
and settings.
ULC SERIES INSTRUCTION MANUAL
05
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