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SUN FROST
OPERATING INSTRUCTIONS FOR THE RFVB - 134A
Installation
The cooling system on the RFVB-134A is located on top of the unit. Since heat is given off by this system, 6”8" of open space above the refrigerator is necessary for ventilation. For convenient access, the SUN FROST
RFVB-134A may be mounted on a cabinet or stand approximately 39 inches (100 cm) high. This height may
be varied according to individual preference.
You will also notice a pair of brackets located on top of the refrigerator, mounted towards the rear of the
"shroud". These brackets allow the unit to be secured to the wall and will prevent the unit from tipping over if a
child pulls on the open door, or if there is an earthquake.
Temperature Control
The sensor for the thermostat is located in the back wall of the refrigerator section. Vaccines are typically
stored between 0°C (32°F) and 8°C (46°F).
The blue line on the thermostat is set at the factory so that the refrigerator section will maintain a constant
temperature of 4°C (38°F). We recommend checking this setting with a thermometer and then adjusting the
thermostat setting so that the refrigerator maintains the desired temperature.
The freezer section is designed for making ice and not for storing frozen vaccines. The temperature in the
freezer section will be about -11°C (12°F) at 21°C (70°F) ambient temperature, and -5°C (23°F) at 43°C
(110°F) ambient temperature.
When the unit is first turned on there will be a cooling down period of about four (4) hours.
Power Supply -- DC Models
SUN FROST refrigerators operating on Direct Current must be connected directly to a battery, which may then
be charged by photovoltaic, wind power, a battery charger, or other appropriate energy source. All that is
required to begin operation is to connect the unit to a battery and adjust the thermostat to the desired setting.
It is important to check polarity when connecting the batteries. Red indicates the positive lead, and black
indicates the negative lead. The compressors used on SUN FROST DC models require the use of an
electronic control unit, which is mounted on the side of the compressor.
DC Electrical Requirements
The compressors used on the DC units can be powered by either a 12-volt or 24-volt power supply. The
electronic control unit on the compressors automatically adjusts the compressor so that it can run on either 12
volts or 24 volts. However, the voltage output of the power supply must be within the appropriate range for
either a 12-volt or a 24-volt operation. To keep your battery voltage from becoming too high, we recommend
that a charge controller be placed between the battery and the solar panels. This will keep the batteries from
being overcharged.
Electrical Specifications
System Voltage
Max. Current Draw (Running)
Max. Current Draw (Starting)
12V Supply
24V Supply
11.0V – 15.5V DC
4.0 – 5.0 amps
15.0 amps
22.0V – 31.0V DC
2.0 – 2.5 amps
7.5 amps
In order to keep voltage loss to a minimum, it is essential to use wire of sufficient size for the connection
between the refrigerator and the battery bank. The table below gives the maximum lead lengths allowable for
any particular wire size.
Lead Dimensions
English
Wire Gauge
#16
#14
#12
#10
#8
#6
#4
#2
Max Length
12V Supply
4 ft.
6
11
17
27
43
68
108
Max Length
24V Supply
8 ft.
13
21
34
54
86
136
216
Lead Dimensions
Metric
Cross Section
2.5 mm2
4
6
10
16
Max Length
12V Supply
2.5 m
4
6
10
16
Max Length
24V Supply
5m
8
12
20
32
Drain Tube
The cooling fins for the refrigerator are located behind the back and side walls of the refrigerator section. A
small amount of condensation will form on the back wall of the refrigerator, which then drains out of the tubes
located in the back corners of the refrigerator compartment. (Before installing the unit, insert the provided 44"
x ¼" drain tube extensions into the outlet tubes which extend from the bottom of the refrigerator and run them
to a drain or convenient collection point.) The drain tubes exit at the bottom of the refrigerator near the rear
wall on both sides of the unit.
The drain tubes may occasionally become clogged with food particles or mold. The tubes can be cleaned by
inserting a flexible wire into them. Mold growth can be prevented by occasionally putting several drops of
bleach in the drain tubes and in the gutter where water collects before running down the drain tubes.
Defrosting the Freezer
Generally, the freezer will need to be defrosted about once a year. Defrosting is advisable when the frost is
1.8 cm (¾ inch) thick on the ceiling and floor of the freezer section. After the first .6 cm (¼ inch) of ice has
formed, the rate of frost build-up will slow. Frost build-up in the freezer section will not affect the performance
of the refrigerator.
The SUN FROST RFVB-134A may be turned off by turning the thermostat to 90°F (32ºC). As the freezer
section warms, the ice will separate from the ceiling and floor and may then be removed in large pieces. To
avoid damage to the liner, do not pry off the ice with sharp metallic instruments.
While the freezer is defrosting, vaccines may be stored in an insulated container and kept cold with ice from
the freezer section. If an insulated container is not available, a box lined with a towel or piece of clothing may
be used, or the refrigerator section may be kept cold by placing several ice packs in the refrigerator section
and then using a temporary cover as a refrigerator door. A taped-on piece of paper or plastic will be adequate
since defrosting will only take about half an hour.
Ice in the Refrigerator Section
Ice will not usually build up on the refrigerator section’s cooling coils; these are located in the back and side
walls of the refrigerator compartment. An exceptionally low thermostat setting may cause some ice to
accumulate. This ice will not affect the operation of the refrigerator unless it is fairly thick. For ice to
accumulate, the back wall must average less than 32ºF (0ºC) (the freezing temperature of water). The ice
build up may be eliminated by raising the thermostat setting a few degrees. In several days, the ice will have
melted and drained through the condensation hole. The thermostat can then be returned to its former setting.
Ice Storage
The freezer in the RFVB can store about 12 kilograms of ice. This ice may be transferred to the refrigerator
section if the cooling system is not in operation due to refrigerator failure, loss of power, or an exceptionally
long overcast period.
12 kilograms of ice stored in the super-insulated refrigerator section will keep the stored vaccines cold for
approximately seven days. If the system's batteries are low because of extremely bad weather, this seven-day
period should be sufficient to let the batteries recharge.
Cleaning
Clean with a soft cloth and a non-abrasive cleanser.
SUN FROST
PO Box 1101
Arcata, California 95518 USA
Tel: 1-707-822-9095
Fax: 1-707-822-6213
www.sunfrost.com
[email protected]
RFVB Wiring Diagram
Electronic Control Unit (ECU) for
the BD35 compressor
Black
Compressor BD35
+
F
D
C
P
T
Red
910 Ohms Resistor
There is a single tube leading to the refrigerator
compartment. This tube can be used to install an
electronic temperature sensor directly in the
refrigerator compartment.
COLDER
Condenser Tubes
Spare Thermostat