DOMETIC Dometic MANUAL REFRIGERATOR DIAGNOSTIC SERVICE MANUAL The Dometic C o r p o r a t i o n 2320 Industrial Parkway Elkhart, IN 46515 219-295-5228 Corporate Office Warranty Department 205 E. Fenn St. LaGrange, IN 46761 219-463-2191 Technical Services 509 S. Poplar St. LaGrange, IN 46761 219-463-4858 Department OS1286 8/89 D-l Diagnostic Service www.westfaliaT3.
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MANUAL REFRIGERATOR DIAGNOSTIC SERVICE ‘MANUAL Table of Contents Page Diagnostic Flow Charts No Operation . . . . . . . . . . . . . D-4-l No 12OV AC Operation . . . . . . . . . D-4-2 No Gas Operation (Piezo Igniter) D-4-3 . . . . No Gas Operation (Automatic Reigniter) .. D-4-4 Operation and Diagnosis ...... D-6- 1 . . . . . . . . . . . . D-8-l Dometic M a n u a l R e f r i g e r a t o r s . Glossary of Service Bulletins Terms . . . . . . . . . . . . D-9-l D-3 www.
MANUAL REFRIGERATOR DIAGNOSTIC FLOW CHART NO OPERATION A. 1 Check Supply Voltage I~>1C o r r e c t 1. 110 Volt Plug 2. Wire Size as Necessary OK B. V Check Fuse NOT OK Correct as Necessary > Replace if Defective OK C. \/ > Correct as Necessary Check wiring NOT OK 1 OK D. Check Switch > Correct as Necessary NOT OK (Page D-6-20, Para. 66) OK E. V Check Thermostat NOT OK , Correct as Necessary ’ Continuity Check D-4-l www.westfaliaT3.
MANUAL REFRIGERATOR DIAGNOSTIC FLOW CHART NO 120 VOLT AC OPERATION A. 1. 2. 3. 4. Check AC Power Refrigerator Plugged in ~=I i Correct as Necessary Breaker Coach Plug OK B. w Check Selector Switch NOT OK Correct as Necessary (Page D-6-20, Para. 66) OK c . V Check Thermostat NOT OK D. IIf Correct as Necessary Continuity Check OK Check 120 Volt Heater NOT OK D-4-2 Correct as Necessary B Ohm’s Reading Bulletin #28 (Page D-9-l 4, D-9-l 5) www.westfaliaT3.
MANUAL REFRIGERATOR DIAGNOSTIC FLOW CHART NO GAS OPERATION - Models Equipped with Piezo igniter 9 . Check Gas Supply OK B. v Check Switch Correct as Necessary (Page D-6-20, Para 66) > NOT OK I OK .C. Check Thermostat NOT OK Correct as Necessary => Continuity Check OK V D. Check Gas Pressure NOT OK Correct as Necessary (Page D-6-13, Para. 37) > OK > Check Flue & Burner NOT OK I Correct as Necessary No Obstructions OK F. Check Piezo Resistance Correct as Necessary (Page D-6-l 8, Para.
MANUAL REFRIGERATOR DIAGNOSTIC FLOW CHART NO GAS OPERATION - Models Equipped with Automatic Reigniter A. Check Gas Pressure NOT OK > Correct as Necessary (Page D-6-13, Para 37) I OK V B. Check Gas Supply > Correct as Necessary (Page D-6-14, Para. 40) NOT OK I C. I v OK Check 12 Volt D.C. Supply > Correct as Necessary NOT OK I I OK Check Switch NOT OK I B Correct as Necessary (Page D-6-20, Para. 66) OK _E. Check Thermostat NOT OK > Correct as Necessary Check for Continuity OK F.
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OPERATION & DIAGNOSIS OF DOMETIC MANUAL REFRIGERATORS D-6-1owners of VW Westfalia T25 / T3 / Vanagon campers www.westfaliaT3.
(1) This is Dometic’s Manual Refrigeration Diagnosis and Troubleshooting program. In this program we will discuss the way an absorption cooling unit operates, and the diagnostic procedures used to troubleshoot the complete refrigerator system. (2) Before we begin extensive troubleshooting procedures on the cooling unit, let’s take a few minutes to see how it operates. THE ABSORPTION SYSTEM (3) The sealed combustion unit contains a mixture of ammonia, water and a rust inhibiting agent.
(4) \ PUMP The cooling unit parts that accomplish this ‘cooling’ or heat extraction process, include the: Boiler or Generator / BOILER l------------WATER SEPARATOR -l I (5) Condenser I I I I GAS TEMPERATUR EXCHANGER - - - - - - - - - - - - _-.I 1 (6) Evaporator D-6-3 www.westfaliaT3.
(7) Absorber ABSORBER THE ABSORPTION SYSTEM CONDENSER EVAPORATOR Because the self-contained cooling unit does not utilize an electric compressor or pump, the cooling coils can be operated from a variety of heat sources. LP gas, 120 volts AC and 12 volts DC heating elements are the most commonly used heat sources for recreational vehicle applications.
c---_-------____---------__----_-__-7 (10) We will now take a closer look at how the cooling unit functions in normal operation. When proper heat is supplied to the boiler, ammonia vapor is produced and rises in the siphon pump, carrying with it a weak liquid ammonia solution. As seen from this drawing, the siphon pump, or pump tube, is an internal arrangement within the boiler section.
I-- U 3) As this process continues, the ammonia and hydrogen vapors become intermixed and flow downward into the absorber vessel. As the ammonia vapor comes in close contact to the liquid ammonia solution in the absorber vessel, the ammonia is absorbed into the liquid solution, allowing the hydrogen vapor to rise up through the absorber coils. After this absorption process, the vapor consists of mostly hydrogen with some traces of ammonia.
(16) THREE REQUIREMENTS FOR PROPER OPERATION 1. Level Since the absorption system utilizes no mechanical pumps or compressors to circulate the refrigerant within the system, proper leveling is required to provide correct refrigerant flow in the gravity-feed system. Without proper leveling, refrigerant within the cooling coils will collect and stagnate at certain areas. When this happens the cooling process will stop.
(19) In recent years Dometic has engineered a new type of cooling unit that utilizes an improved siphon pump tube design which drastically reduces the possibility of permanent damage to the coils if operated in an out-of-level condition, or too much heat is generated at the boiler section. As we can see from this drawing, the siphon pump tube is enclosed in the design and is surrounded by a weak ammonia solution, which will protect the pump tube from abnormally over-heating.
(22) The coach vent system must be able to provide a way to direct the hot air, produced by the action of the cooling unit, out away from the installation of the refrigerator. THREE REQUIREMENTS FOR PROPER OPERATION 1. Level 2. Air Flow (Ventilation) -------- ----- (23) In a good installation there should be as little open space as possible surrounding the sides and top of the refrigerator to achieve proper air flow.
THE ABSORPTION SYSTEM (25) Three things must be remembered when diagnosing a cooling unit: First, circulation within the cooling unit is totally gravitational. This means proper leveling is important. Second, heat - created to boil the ammonia - now has to be dissipated into the surrounding air. Heat from the absorber and condenser must also be dissipated so as to cool the ammonia sufficiently. Third, proper heat application at the boiler section.
(28) One of the faults with a cooling unit is a blockage. This can happen when the unit is operated off-ievel, or if too much heat has been applied to the boiler area. To the touch, this unit will be extremely hot at the boiler with little warmth at the absorber. In other words, no circulation. i_______________________________--________ T G-- BOILER (29) This type of fault means a lost charge. It is known as a ‘leaker’. To the touch, this unit will be warm at the boiler and extremely hot at the absorber.
UNDERSTANDING THE GAS SYSTEM (31) Let’s look at the current Dometic refrigerators and see how the gas flows. SHUT-OFF VALVE (32) Gas flows from the gas line to the shut-off valve and to the connection piece. I =cYz=zc GAS LINE CONNECTION PIECE (33) into the combination gas and electric thermostat (34) COMBINATION GAS & ELECTRIC THERMOSTAT W SAFETY VALVE/ through the safety valve thermocouple (35) PRESSURE TEST HOUSING v ” test housing D-6-12 www.westfaliaT3.
(36) and onto the orifice and burner assembly. Remember that except for the connection piece, all fittings are O-ring sealed. Whenever the system is separated the O-rings must be replaced. ORIFICE & BURNER ASSEMBLY (37) To diagnose the gas system, connect a manometer to the test point. With the thermostat on maximum you must have 11 inches water column pressure at this point. If you have 11 inches pressure, your problem Is to the right of the test point.
(40) The most efficient way to diagnose the gas system would be to first connect the gas manometer to the pressure test point. With the thermostat set at maximum you must have 11 to 12 inches water column pressure for the refrigerator to operate properly. If your manometer reads higher than 11 to 12 inches water column pressure, the tank regulator is adjusted to high, readjust it. Make sure the gas system has at least 50% of the coach’s LP appliances on at the time the system is being adjusted.
Turn on the main gas supply and take a reading. If the manometer now reads 11 inches, the thermostat is defective and must be replaced. (45) If the by-pass screw test shows no change in gas pressure, the problem lies with the gas supply to the refrigerator. Shut off the gas supply, remove the by-pass screw, replace it with one that has an O-ring and turn on gas supply. Remember to check for a gas leak. At this time we will take a look at the rest of the gas system.
(47) Once the gas has been allowed to pass through the safety valve, it flows to the gas jet and burner. These have been specifically designed to eliminate most of the normal maintenance required due to the corrosive contaminants in the gas, as well as soot and rust which fall from the flue pipe. The jet has an orifice made of an industrial ruby which has been laser-beam drilled.
(51) The control assembly will now drop down and can be pulled outward for service. (52) Pictured here is the other model design. Make sure the main gas supply has been shut off and disconnect the gas supply line at the refrigerator. I (53) Remove 3 screws on the burner cover plate. The sheet metal assembly should now slide out from the back of the refrigerator. Remove the 2 screws from the plastic cover. Also the 2 screws on the left and 2 screws on the right of the metal bracket. www.westfaliaT3.
There are 3 screws in the burner area that must also be removed. Please note - these are machine screws, not sheet metal type. It is important for them to be reinstalled in this area only. (56) The control assernbly will now drop down and Warfi ._, fnr crwvir~ can be pulled out..,., 1-1 II”“. On the present line of manual refrigerators we use one of two methods of igniting the burner flame. Shown on the right is the piezo system; on the left is the igniter reigniter.
The igniter reigniter, used on certain Dometic model refrigerators, operates on 12 volt current. On gas operation the igniter senses the resistance through the flame between the electrode and burner. When there is no flame at the burner, the resistance is high and the igniter begins sparking to light the burner. As soon as the flame is lit, the resistance between the electrode and burner drops and the igniter stops sparking.
w THE ELECTRICAL SYSTEM The Electrical System The electrical system consists of a combination switch assembly, heating element and thermostat. The quickest method of diagnosing the electrical system would be testing for continuity of components. Following the wiring diagram, the component that does not show continuity would be suspect. The selector switch should be checked for continuity in the following manner. Remove all wires from the assembly.
(67) IDometicI Before an appliance can be sold to a recreational vehicle manufacturer it must be tested and approved by a nationally recognized testing laboratory for the specific end use All Dometic refrigerators used in intended. recreational vehicles have received this certification. If you require additional service assistance on the basic requirements for the cooling unit operation or the manual refrigeration, please refer to the diagnostic manual.
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Glossary of Terms MANUAL REFRIGERATION 1. ABSORBER: Section of the cooling unit where the hydrogen and ammonia vapor are intermixed in the absorber. Ammonia vapor returns to solution and the hydrogen returns to the evaporator. 2. BOILER: Section of the cooling unit where heat is applied. This is where the ammonia is partially separated from the water. 3. BY-PASS SCREW: Small brass screw located on any Dometic gas thermostat that regulates gas flow in the low flame mode.
(Glossary of Terms . . continued) 13. ORIFICE (JET): A small brass fitting that is mounted on the gas line just prior to the burner. This device incorporates a very small opening to greatly reduce gas flow to the burner. The orifice is cleaned by using an alcohol based solvent and allowing to air dry. 14. PIEZO LIGHTER: Self-contained lighter assembly that is used to generate a spark to light the refrigerator on LP gas.
TYPES OF BLOCKAGE To understand the absorption principle we have set up several refrigerators to inspect and diagnose. Carefully touch the absorber and boiler sections of each unit and record your findings. Proceed with caution as some of these units could be extremely HOT. Listed below are three types of units you will be testing: LI GOOD COOLING UNIT Carefully touch the unit at the boiler box and the absorber area.
q]piGiGq CHANGING THE HINGE POSITION Refrigerator Bulletin R54/7A March 1987 I 2600,2602,2800,2802, 3600,3601,3800 & 3801 MODELS: WHEN CHANGING THE HINGE POSITION: Insure that the door latch assembly operates properly after changing the hinge position from left to right, or vice-versa, with the following checks: R7A54/ If the door(s) open when the latch assembly is in the locked position, adjust the hinge/door assembly. Follow the outlined steps to complete this procedure: 1. A.
(Bulletin R54/7A continued) 5. 6. 7. 8. Hold the door in its new p o s i t i o n a n d carefully retighten t h e h i n g e s c r e w s , being careful not to change the hinge position. Close the door and again determine if the latch is now operational. If more adjustment of the door position is necessary, the center hinge screws may be loosened to reorient the door in the proper position. Again retighten t h e h i n g e screws to allow the latch to operate properly. SPECIAL HINTS TO ADJUST DOOR 1.
PROCEDURE FOR CHANGING COOLING UNIT Refrigerator Bulletin R55/7A April 1 9 8 7 The following categories have been established predicated on similarity of design and procedure for replacement of cooling units. Most Dometic r e f r i g e r a t o r s a r e c o v e r e d in one (1) of these categories.
(Bulletin R55/7A c o n t i n u e d ) INSTALL REPLACEMENT COOLING UNIT: 1. Trim the Styrofoam portion of the cooling 2. 3. 4. 5. 6. 7. unit if it does not go freely into the refrigerator. Apply sealing permagum (sealing tape) on mounting plate (A; FIG. A4). Apply thermal mastic on the evaporator coil (B; FIG. A4). Tighten screws securely to obtain proper contact between the evaporator coil and evaporator flange; otherwise improper cabinet performance may result.
(Bulletin R55/7A) c o n t i n u e d ) 2. Apply sealing permagum (sealing tape) on mounting plate (A; FIG. B5). 3. Apply thermal mastic on the evaporator coil (B; FIG. B5). 4. T i g h t e n s c r e w s s e c u r e l y t o o b t a i n p r o p e r contact between the evaporator coil and evaporator flange; otherwise improper cabinet performance may result. 5. Install the heater element completely back into pocket and plug in. 6. Reinstall capillary tube into proper position. a.
(Bulletin R55/7A c o n t i n u e d ) D . C a t e g o r y #4 RM190 RM2190 3. Apply sealing permagum (sealing tape) on window insulation (A; FIG. D3). 4. Tighten screws securely to obtain proper seal. 5. Install the heating elements completely back into the pocket. 6. Reinstall capillary tube into proper position. 7. Reconnect burner assembly to chimney and replace cover. RM2 192 REMOVAL OF COOLING UNIT: 1. Remove cover and flue tube, then disconnect burner from chimney (FIG. D1). 2.
(Bulletin R55/7A c o n t i n u e d ) 3 (A) SEALING PERMAGUM (Sealing Tape) FIG. E2 FIG. El F. C a t e g o r y #6 RM75 3 RM76 RM77 REMOVAL OF COOLING UNIT: 1. 2. 3. 3. 5. 6. Remove burner protection cover and remove burner from chimney (FIG. Fl). Remove heaters from boiler case (FIG. Fl). Remove evaporator screws (FIG. F2). Remove two (2) screws holding clamp for thermostat capillary tube. Pull capillary tube out gently (FIG. F2). Remove ten (10) screws holding unit from rear (FIG. Fl).
(Bulletin R55/7A c o n t i n u e d 4. Tighten screws securely to obtain proper seal. 5. Install heating elements completely back into the pocket and plug in (FIG. Fl). 6. Reconnect burner assembly to chimney (FIG. Fl ). 7. Reinstall capillary tube into proper position (FIG. F2). 5. Tighten screws securely to obtain proper seal. 6. Install the heating elements completely back into the pocket. 7. Reconnect burner assembly to chimney and replace cover. FIG. F3 6 FIG. G1 / G.
Before You Change That Cooling Unit REFRlGERATOR BULLETIN R61/7A DEC. 1987 PART I. PROPER DIAGNOSIS Cooling units are sometimes diagnosed as being defective when the actual problem is something else. Cooling units are expensive to replace, so it is important to make the correct diagnosis. By using the proper test procedures, you can eliminate all other possibilities before condemning the cooling unit. For a simple method to check gaskets, close the door on a dollar bill, then pull the dollar bill out.
(Bulletin c o n t i n u e d ) Also, make sure the distance from the bottom of the refrigerator to the roof v e n t i s a t l e a s t t h e m i n i m u m dimension given in the Installation Instructions for each model. See FIG. A2. FIG. A2 D. Check the open space above the refrigerator. If this space is 1 1/2 inches or more it must be blocked off to prevent hot air from being trapped above the refrigerator. See FIG. A2.
[Bulletin R61/7A continued) B. 1. 3 3. 4. PERFORMANCE TEST First perform a l l t h e p r e l i m i n a r y checks described previously. Remove all food from the refrigerator and place all controls in the OFF position. Place an accurate thermometer in an ice cube tray, half filled with water, and place the tray in the center of the lower food storage compartment.
(Bulletin R61/7A c o n t i n u e d ) NOTE: The cooling units currently being used are specially designed to prevent overheating of the boiler tube even when operated out-of-level. This special design can be identified by the round insulation box around the boiler, rather than the square-cornered box used on older units. Q FIG. B2 Older Style Boiler Enclosure 7. 8. If the previously mentioned test was performed 90”.
B]1DOmeticl REFRIGERATOR TECHNICAL DATA l RAK1 00 RAK1302 RC15 RC65G RC65K RC150 RC150A RC1 50TEG RC 150TEG RC152 RC160E RC 160E RC1 6 0 T E G RC 1 60TEG M52 l M70 l l l l 9286111001 9286179008 2922000000 N/A N/A 2922302001 2922471020 2942312022 Kerosene Kerosene ------ - 50 (0061667002) Kerosene - - - - - - - - - - - - - - (2928787031) 2922441015 2942312022 -------(2928787031) 2942312121 (2928787031) N/A ________ N/A ________ 9283171008 51 9283191006 4 3 (2002660161) 9283521004 5 2 (
(Bulletin 828 l . continued) RM3601 RM3604 2934803996 53 (2007419191) 215/12 295/120 0173757022 0173754045 2.5 48 17.9 ___ RM3604 RM3800 2934901097 58 (2007419217) 215112 325/120 0173757022 0173742081 2.7 44 17.9 ___ Models that use brass heating elements approximately 3/4’ in diameter. www.westfaliaT3.
(Bulletin #28 c o n t i n u e d ) l Models that use brass heating elements approximately 3/4’ in diameter. NOTE: The formula for calculating amps & OHMS: Watts + Volts (120/12) = AMPS Volts (120) + Amps = OHMS D-9-16 www.westfaliaT3.
Ell[ Dometic 1 BULLETIN # 4 5 MAY 1983 Replacement of cooling units in RM760. Cooling unit 531A will replace 530A in production and service. When installing 331A as replacement for 530A three new holes should be drilled in the cooling flange. 0 J 0 c 0 0 0 0 0 0 New holes + 1 3/16” (29 mm) down. 0 0 0 0 ~ Furthermore the hole for the air channel (no longer necessary) in the burner box should be covered by a piece of aluminium tape (No combustible material must be used).
Kl: Dometic REFRIGERATOR BULLETIN REVISED AUGUST, 1984 #38 CROSS REFERENCE OF REFRIGERATORS MANUFACTURED BY A.B. ELECTROLUX AND DOMETlCARE PROCEDURE CHANGES SUBJECT: Dometicare Procedure An out of warranty cooling unit purchased from Dometic for installation on an Instamatic, Magic Chef, Hadco or GE refrigerator does not qualify for our three year Dometicare cooling unit coverage.
HEATING ELEMENTS 360-460-660-760 Previous literature covering the following models, lists the wattage of 110 volt heading elements as follows: RM360 RM460 RM660 RM760 - 120 - 135 - 175 - 250 watts watts watts watts The ratings that are actually stamped on the replacement heating elements are as follows: RM360 RM460 RM660 RM760 - 135 150 190 275 watts watts watts watts These elements are identical and are covered under the same part numbers.
THE ABSORPTION SYSTEM WATER SEPARATOR VAPOR PIPE A - \i’EAK A~I~IOSIA SOLUTION B c D E F - STROSG AXIhIOSIA SOLUTION LIQUID A~I>lO~IA X313lOSIA VAPOR HYDROGEN GAS HYDROGES 5; A~IllO~;IA V A P O R D-9-20 www.westfaliaT3.
