Dometic DM2862 - Manual (Page 13)

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absoRptioN cooliNg systeM
In an absorption refrigerator system, ammonia is liquefied in
the finned condenser coil at the top rear of the refrigerator.
The liquid ammonia then flows into the evaporator (inside the
freezer section) and is exposed to a circulating flow of hydro-
gen 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 before the cooling unit is
fully operational.
The tubing in the evaporator section is specifically sloped to
provide a continuous movement of liquid ammonia, flowing
downward by gravity through this section.
Sodium chromate is used for corrosion protection (less than
2 weight % of the coolant).
leVeling the refrigerator
Leveling is one of the requirements for proper operation with
absorption refrigerators. to ensure proper leveling the vehicle
needs to be leveled only so it is comfortable to live in (no no-
ticeable sloping of floor or walls).
Any time the vehicle is parked for several hours with the refrig-
erator operating, the vehicle should be leveled to prevent this
loss of cooling.
If the refrigerator is operated when it is not level and the
vehicle is not moving, liquid ammonia will accumulate in sec-
tions of the evaporator tubing. This will slow the circulation
of hydrogen and ammonia gas, or in severe cases, completely
block it, resulting in a loss of cooling.
When the vehicle is moving, the leveling is not critical, as the
rolling and pitching movement of the vehicle will pass to either
side of level, keeping the liquid ammonia from accumulating in
the evaporator tubing.
autoMatic eNeRgy selectoR systeM
The refrigerator is equipped with an automatic energy selector
system. The user turns the refrigerator on and then, the refriger-
ator automatically selects the most suitable energy source avail-
able, either 120 V AC or lP gas operation. The system 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).
On 3-way models, the control system can manually be set to
DC mode (DC operation). The DC mode overrides all other
operating modes.
The refrigerator controls will work down to 9.6 V DC.
MoDes of opeRatioN
auto mode - aeS/auto mode
When operating in AUTo - AES/AUTo mode, the AUTo -
AES/AUTo mode indicator lamp is illuminated. The control sys-
tem will automatically select between AC and GAS operation.
AC has priority over GAS. Should AC become unavailable, the
system automatically switches to GAS. As soon as AC becomes
available again, the control will switch back to AC regardless
of the status of the GAS operation.
If the ChECK indicator lamp is illuminated the controls have
failed to ignite the burner in the GAS mode. To restart an igni-
tion attempt with the ChECK lamp illuminated (or to turn off
the ChECK lamp), press the oN/oFF button oFF and back
ON again. The control system activates the ignition system and
makes three attempts to light the burner for a period of approx.
45 sec. at two minutes interval. Should 120 V AC become
available while the ChECK indicator lamp is on, the ChECK
lamp will not turn off until the ON/OFF button is pressed OFF
and then ON again.
gaS mode
RM2351, RM2451, RM2551, DM2652 & DM2852:
When operating in GAS mode, the AUTo mode
indicator lamp will be off.
RM2354, RM2454, RM2554, DM2662, DM2663, DM2862,
DM3862, NDM1062 & NDR1292: When operating in GAS
mode, the GAS mode indictor lamp is illuminated.
This mode provides LP gas only. The control system activates
the ignition system and attempts to light the burner for a period
of approx. 45 sec. at two minutes interval. If unsuccessful, the
ChECK indicator lamp will illuminate.
To restart GAS operation, press the oN/oFF button to oFF
and then back ON. The control system attempts a new ignition
sequence.
Purging air from the lines
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, turn the refrigera-
tor off and on by pressing the oN/oFF button. If the flame is
not lit within 45 seconds, turn the refrigerator off and back on
again. This procedure can be repeated 3 to 4 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 that all manual
shutoff valves in the lines are open.
refrigerator oVerView
operating instructions
wARNINg
FIRe OR eXPLOSION hAZARD. when refu-
eling or parked near gasoline pumps, shut off all
LP gas appliances. Failure to heed this warning
could cause a fire or explosion resulting in death
or severe personal injury.
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