Dometic RM3962, Service Manual

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8
most lP gas appliances used in recreation-
al vehicles are vented to the outside of the
vehicle. When parked close to a gasoline
pump, it is possible that the gasoline fumes
could enter this type of appliance and ignite
from the burner flame, CAUSING A FIRE OR
an eXPloSIon.
for your Safety, when refueling, shut
off all lP gas appliances which are vented
to the outside.
refrIgerator oVerVIeW
aBSorPtIon coolIng SyStem
In an absorption refrigerator system, ammonia is liquefied
in the finned condenser coil at the top rear of the refrig -
erator. The liquid ammonia then flows into the evaporator
(inside the freezer section) and is exposed to a circulat-
ing flow of hydrogen gas, which causes the ammonia to
evaporate, creating a cold condition in the freezer. When
starting this refrigerator for the very first time, the cooling
cycle may require up to four hours of running time be-
fore the cooling unit is fully operational. The tubing in the
evaporator section is specifically sloped to provide a con -
tinuous movement of liquid ammonia, flowing downward
by gravity through this section.
ImPortance of leVelIng
If the refrigerator is operated when it is not level and the
vehicle is not moving, liquid ammonia will accumulate in
sections of the evaporator tubing. This will slow the circu-
lation of hydrogen and ammonia gas, or in severe cases,
completely block it, resulting in a loss of cooling. Any time
the vehicle is parked for several hours with the refrigera-
tor operating, the vehicle should be leveled to prevent this
loss of cooling. The vehicle needs to be leveled only so it
is comfortable to live in (no noticeable sloping of floor or
walls). When the vehicle is moving, the leveling is not criti-
cal, as the rolling and pitching movement of the vehicle
will pass to either side of level, keeping the liquid ammo-
nia from accumulating in the evaporator tubing.
oPeratIon
Before starting the refrigerator, check that all the manual
gas valves are in the ON position. DO NOT forget the
manual shutoff valve on the rear of the refrigerator. This
refrigerator is equipped with a control system, which can
be set to automatically select either 120 volt AC or LP gas
operation (AUTO mode), or if desired LP gas only (GAS
mode).
NOTE: Do not continue to reset GAS operation if the
CHECK indicator lamp continues to be illuminated after
several tries.
automatIc energy Selector control
SyStem
T
he refrigerator is equipped with an automatic energy se-
lector control system. The user turns the refrigerator on,
selects the desired temperature and then, the refrigera-
tor automatically selects the most suitable energy source
available (either 120 VAC or LP gas operation). The sys-
tem can be set by the user to be fully automatic (AUTO
mode is selected) or to operate on LP gas only (AUTO
mode is off). The refrigerator controls will work down to
9.6 volts DC.
modeS of oPeratIon - auto and gaS
AUTO mode
When the refrigerator is in AUTO mode, it automatically
uses the most efficient energy source that is available
for operation. Should a more efficient energy source be -
come available during operation, the refrigerator controls
change from the current energy source to the more ef-
ficient energy source as follows:
1. AC operation
(if 120V AC is available). AC operation is
only possible in AUTO mode.
2. GAS operation (if 120V AC is not available).
Before starting the refrigerator:
• Check that all manual gas valves are in the on posi-
tion.
•
To start the refrigerator :
1. Press the ON/OFF button.
2. Select operation mode:
• AUTO mode ( AC and GAS )
Press the AUTO/GAS mode selector button
( if not already on ).
• GAS mode ( gas operation only ).
Press the AUTO/GAS mode selector button to turn off
the AUTO mode ( if not already off ).
GAS mode (manual LP gas operation)
When AUTO mode is turned off, the refrigerator uses
gas as energy source - even if AC is available.
Startup
The thermostat controls both the gas and electric opera-
tion. Thus it is not necessary to reset each time a different
energy source is employed. The adjustable thermostat
ranges from 1 - 5 where 5 signifies the coldest temperature
setting. After the initial start-up, adjust the thermostat by
pressing the TEMP. SET button repeatedly until the desired
setting is displayed.
adjusting the thermostat
turning off the refrigerato r
The refrigerator may be shut off while in any mode of op-
eration by pressing the main power ON/OFF button (OFF
position). This shuts off all DC power to the refrigerator,
including the interior light. If the refrigerator will not be
in operation for a period of weeks, it should be emptied,
defrosted, cleaned and the doors left ajar.
Make sure that a continuous 12V DC supply is avail-
able for the electronic control to function.