Dometic RM36O service manual Mount the shutter as described above, Absorption Cooling Unit

Replacement of evaporator door gasket on RM360,

RM460, RM660

1.Remove the door as previously described.

2.Unscrew the hinge plates (A fig. 13).

3.Put shutter on a flat surface with the sealing gasket up.

4.Pry the shutter front away from the inner pan by means of a screwdriver.

CAUTION: It is of great importance that the screw driwer is applied in front of one of the plastic tongues (B fig. 13) which hold the inner panel and the shutter front to- gether.

5.Replace the sealing gasket round the in- ner panel and snap the inner panel with sealing gasket into the shutter front until the tongues snap in position.

6.Mount the shutter as described above.

Fig.13

THE ABSORPTION COOLING UNIT

Sealed system construction

The sealed system of the absorption refrigerator is constructed of welded steel piping which con- tains the refrigerant charge. The charge consists of ammonia, hydrogen and water. There are no mo- ving parts associated with the absorption system.

If an excessive vaporizing of the ammonia within the boiler occurs due to the reasons above, the liquid mixture in the boiler becomes very weak and the pump will cease to operate, which means that the circula- tion of liquid stops with the result that the eva- porator inside the cabinet ceases to produce coo- ling.

When servicing an absorption system refrigerator, do not puncture or break the piping. Should a break occur and ammonia contact the skin, wash the affected area immediately with clear water. Do not attempt to open the valve on the absorber vessel. The valve is covered with a plastic can and should never be removed.

OPERATION ANALYSIS FOR COOLING UNIT

It is obviously important that all external fac- tors affecting the unit should be checked properly before a unit is condemned as faulty and that empha- sis has been placed upon the necessity for correct installation, upright refrigerator, correct heat in- put, baffle position, etc. Check the size and the wattage of the electric heater and make sure that the heater element is inserted to its full length in its pocket. If the electric heater is only part- ly inserted, the heat distribution will be incorrect, causing an excessive vaporizing of the ammonia within the boiler when operating on electricity. The same symptom can show up with too much or too little

heat input either on electric or on gas operation and also if the refrigerator had been operating in an off-level position or with inadequate ventila- tion.

Such a blockage of the unit in the liquid circuit ist most usually made evident by signs of overhea- ting on the vapour pipe leading from the boiler to the condenser, the paint on this pipe being bliste- red and the metal becoming discouloured.

To remedy this fault it is recommended to remove the unit or refrigerator complete whenever possible and to allow sufficient time to- cool down the unit. Turn the unit or refrigerator upside down several times, so that the liquid in the absorber vessel can be mixed with the liquid in the boiler. This procedure will restore the liquid balance to the unit.

The temperatures on various parts of a unit vary continuously when it is operating on thermostatic control and it is impossible to base a judgment on the symptoms given unless the refrigerator has been operating continuously on fully correct heat input for at least 5 hours, and preferably 12 hours, prior to examination. In many cases this can be arranged by a telephone call to the customer, asking him to switch the thermostat to "MAX" on the day before the inspection call. If after 12 hours' operation on "MAX" the performance is satisfactory, the unit is not at fault unless the complaint is one of varying or intermittent performance. In this connection