Dometic RM3962 user manual Operating the refrigerator, Absorption cooling system

refrigerator overview

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 cool- ing cycle may require up to four hours of running time before the cooling unit is fully operational. The tubing in the evapora- tor section is specifically sloped to provide a continuous move- ment of liquid ammonia, flowing downward by gravity through this section.

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 so it is comfortable to live in (no noticeable 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 vehi- cle is not moving, liquid ammonia will accumulate in sections of the evaporator tubing. This will slow the circulation of hy- drogen 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 Control system

The refrigerator is equipped with an automatic energy selector control system. The user turns the refrigerator on, selects the desired temperature and then, the refrigerator automatically selects the most suitable energy source available (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).

The refrigerator controls will work down to 9.6 volt 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 become available during operation, the refrigerator controls change from the current energy source to the more efficient 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).

GAS mode (manual LP gas operation)

When AUTO mode is turned off, the refrigerator uses gas as energy source - even if AC is available.

! 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.

operating the refrigerator

! WARNING

FIRE HAZARD. Before lighting the gas burner, after that the RV has not been used for some time, please check that the gas path between the burner jet and the burner tube has not been obstructed. Failure to heed this warning could cause a fire resulting in personal injury

SOLENOID VALVE .	NUT
	THERMOCOUPLE
INLET FITTING
MANUAL SHUTOFF VALVE .
Shown in open position
	SPARK ELECTRODE
PRESSURE TEST PORT .	BURNER TUBE
BURNER JET .	BURNER MOUNTING SCREW

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