Zero Zone RVZC30, Installation And Operation Manual

RVZC30 (and BB/T/TBB/WA), RVZP30 (and BB/T/TBB/WA), RVC24

21

0407

ELECTRICAL

! CAUTION !

DISCONNECT POWER TO THE CASE

BEFORE SERVICING ELECTRICAL COMPONENTS TO

AVOID PERSONAL INJURY AND DAMAGE TO THE UNIT.

Figure 21 for 30” door cases and Figure 22 for 24” door
cases shows the typical wiring diagram for a freezer equipped
with electric defrost.  Figure 23 shows the typical wiring dia-
gram for a freezer equipped with hot gas defrost.  Each case
is provided with a wiring diagram located in the electric box
that shows the exact wiring of the case.

There are many control options available for multiple case
defrost systems. Wiring diagrams and instructions can be
obtained by contacting Zero Zone’s Service Department.

External wiring should be sized according to the amperage
rating stamped on the serial plate. The serial plate is located
on the ceiling inside the left-hand door. Typical electrical val-
ues are shown on specification sheets for each of these cases
in the bag attached to the case or are available at
www.Zero-Zone.com. All internal wiring has been done at the
factory. Cases with standard wiring have their control wires
terminated in the electrical compartment located behind the
kick rail at the right end of the case. A terminal block has been
used to simplify field connections.  An electrical box is mounted
on the top of the unit for cases equipped with the optional top
mount electrical connections.

All wiring must comply with the National Electrical Code and
all local codes. After installation of the equipment, correct op-
eration of the electrical circuits and controls and defrost op-
eration and termination  should be verified.  All operating volt-
ages and amperages should be measured and recorded.

OPTIONAL ELECTRICAL WIRING

Single Point Connection

The “single point” connection system is designed to reduce
the time required to install and wire one display case with one
condensing unit.  Figure 24 is a typical diagram for this sys-
tem.

All of the display case controls, including the disconnect switch,
time clock, temperature control, and defrost temperature con-
trol  are installed behind the kick plate and prewired.   The
liquid line solenoid valve is installed in the liquid line and wired.

The power to operate the display case is connected at the
case disconnect switch.  The power to operate condensing
unit is connected in the condensing unit control panel.  There
are  no interconnecting wires between the condensing unit
and display case.

The controls operate the system as a pump down defrost.
When the display case begins defrost the liquid line solenoid
valve, fans and anti-sweat heaters are de-energized.  The
defrost heaters are energized.  The compressor continues to

run and pumps down the coil.  The compressor cycles off on
its low-pressure control.  If there is any residual liquid left in
the coil, the suction line pressure will rise and the compressor
may turn on and pump down the coil.

The liquid line solenoid is energized at the end of the defrost
cycle and the defrost heaters are de-energized. The suction
line pressure rises and the compressor starts.  When the evapo-
rator reaches operating temperature the delay thermostat (klix-
ons) will close energizing the fans and anti-condensate door
heaters.

Master Satellite Connection

The “master satellite”  connection system allows one condens-
ing unit to be connected to multiple cases.  Figure 25 shows a
typical diagram for this system.

All of the display case controls including the disconnect switch,
time clock, temperature control, and defrost temperature con-
trol are installed behind the kick plate and prewired.  The liquid
line solenoid is prewired but is not installed in the liquid line.

The power to operate each display case is connected at each
cases’ disconnect switch.  The power to operate condensing
unit is connected at the condensing unit.  There are no inter-
connecting wires between the condensing unit and display case.
There are interconnecting wires that need to be connected
between the cases.  The liquid line solenoid valve needs to be
installed in the common liquid line before the liquid is distrib-
uted to the cases.

The controls operate the system as a pump down defrost.  When
the display case begins defrost, the liquid line solenoid valve,
fans and anti-sweat heaters are de-energized.  The defrost
heaters are energized.  The compressor continues to run and
pumps down the coil.

The master case contains the time clock.  Interconnecting case
wiring allows the master case to control the satellite cases.
When defrost is initiated in the master case, it sends an elec-
trical signal to each case to energize the defrost relay and
initiate a defrost in all of the satellite cases.  A second set of
interconnecting wires are connected in series between each
of the cases.   Each case defrost heater is de-energized when
the coil reaches the defrost termination temperature.  An addi-
tional signal is relayed to the next case indicating that the ter-
mination temperature has been reached.  When all of the cases
have reached termination temperature, the defrost termination
circuit is complete and the defrost is terminated.

The liquid line solenoid is energized at the end of the defrost
cycle and the defrost heaters are de-energized. The suction
line pressure rises and the compressor starts.  When the evapo-
rator reaches operating temperature, the delay thermostat (klix-
ons) will close, energizing the fans and anti-sweat door heat-
ers.