Ac Voltage; Auto Mode; Ac Voltage Requirements - Dometic RM 3762 Service Manual

description of operating modes

auto mode

When operating in the AUTO mode, the AUTO mode
indicator dot is lit. The control system will automatically
select between AC and GAS operation with AC having
priority over GAS. If the control system is operating with
AC energy and it then becomes unavailable, the system
will automatically switch to GAS. As soon as AC becomes
available again the control will switch back to AC opera-
tion. gas operation (120 volts AC is not available): The
control system will activate the ignition system and will
make three attempts to light the burner for a period of
approximately 45 seconds with two minutes rest (purge)
interval. If unsuccessful, LP will be flashing (the message
alternates between LP and the temperature) in the dis-
play. To restart an ignition attempt with LP flashing in the
display turn unit off, wait a few seconds and turn back on.
The control system will attempt a new ignition sequence.
If 120 volts AC becomes available while LP is flashing, the
refrigerator will operate on AC but the LP flashing will not
turn off until the main power ON/OFF button is pressed to
the OFF then ON position.
gaS mode
When operating in the GAS mode, the AUTO indication
dot will be off and the LP indication dot is lit. This mode
provides LP gas operation only. The control system will
activate the ignition system and will make three attempts
to light the burner for a period of approximately 45 sec-
onds with two minutes (purge) interval after each trial. If
unsuccessful, the display will flash LP. To restart GAS
operation, press the main power ON/OFF button to the
OFF and then ON position. The control system will at-
tempt a new ignition sequence. If the refrigerator has not
been used for a long time or the LP tanks have just been
refilled, air may be trapped in the supply lines. To purge
the air from the lines may require resetting the main power
ON/OFF button three or four times. If repeated attempts
fail to start the LP gas operation, check to make sure that
the LP gas supply tanks are not empty and all manual
shutoff valves in the lines are turned on.
to Shut off the refrigerator
The refrigerator may be shut off while in any mode of
operation by pressing the main power ON/OFF button
to the OFF position. This shuts off all DC power to the
control system including the interior light.
low ambient control
In colder weather, the temperature inside the absorption
refrigerator lower box tends to hold the temperature inside
for a very much longer period of time, with very long pe-
riods in between ON/OFF cycling of the heat source; this
is OK for any food product inside the refrigerator cabinet,
but is not OK for the freezer compartment (if it happens to
have perishable product inside). Because of the long time
in between cycling ON/OFF, there is a chance that the
temperature may rise above freezing in the freezer com-
partment, resulting in food spoilage. This is why we have
a low ambient control. If it so happens that the tempera-
ture in the refrigerator has satisfied the thermostat set-
ting, and the CUT-OUT threshold has been reached, the
refrigerator cycles OFF. If the temperature remains at
lower than the CUT-IN threshold for 35 minutes or longer,
the LAC output will be activated; this output, typically, is
connected to the interior lamp situated inside the refrig-
erator compartment. The warmth generated by the lamp
slowly raises the temperature inside the refrigerator cabi-
net to the CUT-IN threshold; when CUT-IN is achieved,
the refrigerator cycles back ON again. At this point, the
LAC output is de-activated, and the interior lamp turns
OFF. The refrigerator will now assume normal operation,
and will continue to cool until thermostat is satisfied once
more. If it should so happen that CUT-IN is not achieved
again within 35 minutes, the LAC process will be initiated
once more (and any time thereafter) as required.
limp mode
This control system contains a feature where it will contin-
ue to operate the cooling system in event of a failure of a
major operating component. If the power modules cannot
communicate, the control system will revert to full AUTO
operation selecting the best energy source available with
AC first and GAS second priority. The temperature setting
will be maintained at mid-position. If the control cannot
read the temperature sensor, then the control will run the
cooling unit continuously at the energy source available.
The refrigerator will continue to operate in this mode in-
definitely or until a new sensor is installed and the system
is reset.
SectIon 2 ac Voltage

ac Voltage reQuIrementS

this is an energized circuit. Shock can occur
if not tested properly. testing is to be done
by a qualified service technician.
The refrigerator is a 120 volt AC, 60 Hz appliance. The
proper operating range is 100 to 132 volts. If voltage
drops below 100 volts, cooling efficiency will decrease
with voltage decrease. Check the AC volts at the recepta-
cle where the refrigerator is attached. If voltage is outside
of the proper operating range, correct the power source
problem.
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