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45
NX6 / NX8 / NXA Models
Refrigerator Service Manual
2-Way Models
18 AWG is the minimum AWG size wire that can be used for
connecting DC power to 2-way models. The in-line fuse for
overload protection must not exceed 6 amps.
3-Way Models
The distance between the RV DC power source and the
power board DC power connection terminals dictates the
AWG size wire that must be used. If the distance from the DC
power source is:
•
20 feet or less – 10 AWG or a larger gauge wire must
be used. The size fuse for circuit overload protection
must not exceed 30 amps.
•
Over 20 feet – AWG 8 or a larger wire gauge must be
used. The size fuse for circuit overload protection must
not exceed 40 amps.
AC/DC Converter as Power Source
The power board must be supplied with 12VDC only from the
fi
ltered output (battery side) of a converter.
Un
fi
ltered voltage (commonly referred to as AC ripple) output
of AC/DC converters can cause the electronic controls to set
false fault codes. It can also turn off the refrigerator or prevent
the refrigerator from turning off.
ELECTRICAL REQUIREMENTS AND COMPONENTS
DC Voltage Requirements and Polarity
Operating controls require 10.5 to 15.4VDC to operate. The
positive wire lead (
+
) connects to power board terminal
12VDC
;
the negative wire lead (
–
) connects to terminal
GND
.
Power Board DC Fuse
The controls circuit fuse is a standard 5 amp (tan color)
automotive blade type fuse. It is located on the power board,
labeled
F1.
DC Heater–3-Way Refrigerators Only
The DC heater, shown in Fig. 29, is a cartridge type heater.
The DC heater is rated for 280 Watts (20 amps, at a nominal
14VDC). Heater resistance should be between 0.67 and 0.73
ohms.
When AUTO DC or DC-Manual Mode does not maintain
refrigeration and ventilation is correct:
•
Measure DC voltage input to the power board.
•
Measure the heater's amp draw.
•
If amp draw is not as speci
fi
ed, measure the heater's
resistance at ambient temperature.
The DC heater must be inserted into the heater tube until the
stop bead makes full contact with the tube's rim. See Fig. 29.
DC Heater Circuit Fuse
The DC heater circuit fuse is a standard 30 amp (green)
automotive blade type fuse. It is located on the DC board,
labeled F1.
The AUTO DC and DC-Manual Mode operation
maintain refrigeration only.
NOTE
DC Power Wiring Requirements
Fig. 29 - DC Heater
Yellow Wire Leads
Stop Bead
!
WARNING
Do not wire the heater(s) direct!
Wiring heater(s)
direct bypasses control safety devices and creates
the potential for an electrical
fi
re.
!
WARNING
Never replace a fuse with a higher amp rated fuse.
Always use the speci
fi
ed fuse.
!
WARNING
Never use undersized wires to supply DC power to
the power board. The use of undersized wires can
cause low voltage and high amp draw conditions. The
high amp draw caused by a circuit using undersized
wires will cause the wire to overheat and creates an
electrical
fi
re hazard.
!
WARNING
Never replace a fuse with a higher amp rated fuse.
Always use the speci
fi
ed fuse.
