25
15 & 24 INCH SERVICE MANUAL
SEQUENCE OF OPER ATION
The operating system consist of these components.
ELEC T RONIC CONTROL BOA RD
– Main control of the entire unit’s functionality. The control board is located in the
interior ceiling for all models except (TUF & DZ) TUF board location is behind the rear back cover. DZ boards are
located in the interior ceiling of the center mullion.
COMPRESSOR
– Variable speed and single speed compressors depending on version. Please see page 47
CONDENSER
FAN
MO T OR
– Located behind the rear panel of the unit. The condenser fan should always run while the
compressor is running.
24" units - 120VAC condenser fan motor
15" units - 10VDC condenser fan motor
E VAPOR AT OR
FAN
MO T OR
– Located behind the interior back cover. The evaporator fan motor will cycle off with the
refrigeration cycle on refrigerators. On wine units the evaporator fan will run all the time. The fan will always shut off
when the door is opened.
ONE
COMPA R TMENT
PROBE
(Labeled with two blue stripes on "A"versions) (solid blue on "B"versions) – this sensor
controls the cut in and cut out of the refrigeration system.
ONE
E VAPOR AT OR
PROBE
(Labeled with 1 blue stripe on "A"versions) ( solid blue on "B"versions) – this sensor
controls the defrost function. (Described in detail in the "Defrost" section of this manual)
When power is supplied, the LCD will show a software version code for a minimum of 25 seconds. This is for
manufacturing process only.
From the “off” to the "on" position using the interface power button, the following will happen:
1. Interior LED lights will illuminate.
2. Display readout will show interior cabinet temp based off the compartment probe.
3. After a 2-minute delay the refrigeration system will start.
The refrigeration system (compressor, condenser fan motor, evaporator fan motor) will run until cut out temperature is
reached.
PLE ASE NO TE: THE CUT OUT TEMPER ATURE IS BASED ON THE COMPA R TMENT PROBE, NO T THE DISPL AY
T EMPER ATURE. OUR DISPL AY TEMPER ATURE IS A CA LCUL ATION AND IS NO T REFLEC TING RE A L TIME TEMP.
Once the cut out temperature is reached the we will shut the refrigeration system off.
The cycle will repeat when the compartment probe tells the control board to cut back in.
NO TE: THE CONTROL HAS A PRESE T 7 MINUTE ANTI SHOR T CYCLE.
DUA L ZONE
The TWC-24DZ has two zones which can be independently set for different temperatures.
Each zone has its own display, evaporator coil, evaporator fan and probes.
The zones share the compressor, condenser coil, and condenser fan motor.
Refrigerant is directed to either zone through a bi-stable solenoid valve.
Only one zone can be cooled at a time.
The control continually checks to see which zone is demanding for cooling. If both zones need cooling, the control will
switch from cooling one zone to the other every 20 minutes.
NO TE: THE UPPER ZONE HAS PRIORIT Y WHEN THE CA BINE T IS FIRST POWERED ON AND WILL ONLY STA R T T O
COOL THE LOWER A F TER THE UPPER ZONE SE T POINT HAS BEEN ME T (ONLY ON STA R T UP)
