Modes Of Operation; Warning Attention; Gas Mode; Ac And Dc Modes - Norcold N180.3 Service Manual

Modes of Operation

The controls are designed so that each mode of operation is
independent of the others. All electricity could be cut off and the
refrigerator would still operate in the GAS mode.

Gas Mode

The GAS mode uses a thermocouple system to produce a self-
generating power (millivolts). The Thermocouple, when heated
by the burner flame, produces enough millivolts to hold the safety
valve open. A loss of flame de-energizes the safety valve and
shuts the propane gas down. An Interrupter device is coupled in
series with the thermocouple so that the milliamperes cannot flow
to the Safety Valve (part of the Control Valve) until the Interrupter
contacts are shunted (jumpered). The shunt is provided by the
Selector switch when it is switched to GAS mode. The Selector
switch not only serves as a mode selector but also as an interlock
between modes so that two sources of power cannot be energized
simultaneously.
The GAS mode utilizes an adjustable GAS control. The control can
be manually adjusted to meter the fixed amount of propane gas
to the burner thereby acting as a temperature control to maintain
cabinet temperature.
Unlike an automatic gas control, this
NOTICE
control does not cycle the flame from
high fire to low fire as with other types
of RV refrigerators. If the cooling load
changes, the GAS control must be
manually adjusted to maintain the same
temperature.
The gas ignition method uses a piezo spark ignitor requiring a
manual ignition of the burner. See the Lighting Instructions.
To change the desired temperature setting, push and turn the
gas control to the HI, MED, or LO position. HI is the coldest
temperature setting.
The gas control changes the amount of
NOTICE
propane gas that goes to the burner. It
is not an automatic gas control. It does
not change the flame from high fire to
low fire. If the cooling load changes, you
must manually change the gas control to
maintain the same temperature inside the
refrigerator.
When the outside air temperature is less than 50° F (10° C), the
refrigerator may have a tendency to freeze food at the colder
temperature settings. To reduce the tendency to freeze food:
■ Turn the gas control to the LO position.
■ Keep the refrigerator full.
■ Put foods that are more likely to freeze on the lower shelf.
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AC and DC Modes

The AC mode is thermostatically controlled by an adjustable
thermostat. The thermostat has a capillary sensor attached to the
cooling fin. The AC electric heater will cycle in response to the fin
temperature to maintain the cabinet temperature. The DC mode is
not thermostatically controlled. When operating in DC Mode, the
DC heater is on continually.

DC Operation Precautions

The refrigerator is made to operate on DC power while the vehicle
is "in transit" and neither AC power nor propane gas sources are
available. Operate the refrigerator on DC power only while the
vehicle engine is running.
■ For the refrigerator to operate correctly on DC power, the bat-
tery must be in a fully charged condition.
■ For the battery to be fully charged at all times during refrigerator
operation, the vehicle engine must be running and the battery
charging system must be in good operating condition.
■ While the vehicle engine is running, make sure the voltage at
the DC power supply leads at the refrigerator is more than 11.5
VDC.

Lighting Instructions

Before ignition or start up of the refrigerator:
■ Be sure the air flow in the lower intake vent, through the refrig-
erator coils and condenser, and out the upper exhaust vent is
not blocked or decreased.
■ Be sure there are no combustible materials in or around the
refrigerator.
1. Open the valve at the propane gas storage tank.
2. Turn the mode selector switch [207] to the propane gas
position ( ).
3. Turn the gas control to the HI position.
4. Push and hold in the gas control [294] and in rapid succes-
sion push in the piezo igniter several times for about five (5)
seconds:
WARNING
!
ATTENTION
• When a flame is present, and the flame meter [217] moves
into the green area, wait about five (5) seconds and then
release the gas control.
• If the flame meter does not move into the green area or does
not remain in the green area, wait about five (5) minutes
and do this step again.
5. Turn the gas control to the desired temperature setting.
11
Do not hold the gas control in more than
30 seconds. If there is no flame in this
time, wait at least five (5) minutes before
you try ignition again. If you continue to
hold in the gas control, gas will collect
in the burner area. This could cause a
fire or explosion and result in dangerous
personal injury or death.
SERVICE MANUAL