Installation & Operation • 13
INSTALLATION & OpERATION
OPTIONAL ELECTRICAL WIRING
Single Point Connection (Low Temp)
All of the display case controls, including the disconnect switch and the electronic case controls are installed behind the kickplate in the
electrical enclosure 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 the 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 low temperature evaporator reaches operating temperature, the fans and anti-condensate door heaters
are energized.
Single Point Connection (Medium Temp)
The “single point” connection system is designed to reduce the time required to install and wire one display case with one condensing unit. For
a typical diagram for this system
.
All of the display case controls, including the disconnect switch and electronic case controls, are installed behind the kickplate in the electrical
enclosure 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 the 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 is de-energized.
The fans and anti-sweat heaters remain energized during defrost. 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. The suction line pressure rises and the compressor starts.
Master Satellite Connection (Low Temp)
The “master satellite” connection system allows one condensing unit to be connected to multiple cases. For a typical diagram for this system
.
All of the display case controls, including the disconnect switch, time clock, temperature control, and defrost temperature control, are installed
behind the kickplate in the electrical enclosure 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 case’s disconnect switch. The power to operate condensing unit is connected
at the condensing unit. There are no interconnecting 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
distributed 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.
