Zero Zone Highlight MERCHANDISER 1RHCC30, Руководство по установке и эксплуатации

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14 • Installation & Operation
INSTALLATION & OpERATION
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 electrical 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 is connected in series between each of the cases. Each case defrost heater is de-energized when
the coil reaches the defrost termination temperature. An additional signal is relayed to the next case indicating that the termination 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 evaporator reaches operating temperature, the delay thermostat (Klixon) will close, energizing the fans
and anti-sweat door heaters.
Note: When using a Carel controller, the system will still function as a pump down system, but the Carel defrost function controls the defrost
termination of each case independently and requires a defrost sensor coming from each satellite case to the master case. Contact the Zero
Zone Service Department for specific operating characteristics.
Master Satellite Connection (Medium Temp)
The “master satellite” connection system allows one condensing unit to be connected to multiple cases. See Figure 30 on page 44 and See
Figure 31 on page 45.
All of the display case controls, including the disconnect switch, time clock, and temperature control, are installed behind the kickplate 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 the 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 is de-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 electrical signal to each case to initiate a defrost in all of the satellite cases. A second set of
interconnecting wires is connected in series between each of the cases.
The liquid line solenoid is energized at the end of the defrost cycle. The suction line pressure rises and the compressor starts.
Defrosting - Low Temp
GENERAL
Periodic defrosting to keep the coil free of frost is accomplished automatically by a time clock used in conjunction with an electric or hot gas
defrost method.
For best results, temperature termination of defrost is strongly recommended on Zero Zone cases.
DEFROST SETTINGS AND CONTROLS
Electric Defrost
Frequency: One electric defrost per day is recommended.
Time of day: Nighttime defrosting is preferred to avoid periods of shopping or stocking.