RM2612 RM2652 RM2812 RM2852 Service Manual

RM2612 RM2652 RM2812 RM2852 Service Manual
SERVICE TIPS
81 Dometic
REFRIGERATORS
Models
RM2612
RM2652
OS1927 4/96
Copyright 1996 The Dometic Corporation
RM2812
RM2852
THE MOST COMMON SYSTEM PROBLEMS ASSOCIATED WITH THE
RM2612, RM2812, RM2652, RM2852 REFRIGERATORS
SYMPTOM
..
CAUSE
REFRIGERATOR SECTION
1.
No operation - no panel lights
Operation
DC Volts
Fuse
Wiring
Upper Circuit Board
Lower Circuit Board
2.
No operation - has panel lights
Operation
DC Volts
Thermistor
Fuses
Wiring
Lower Circuit Board
3.
No AC operation - operates on gas mode
Operation
AC Volts
Fuse
Heating Element
Wiring
Lower Circuit Board
4.
No Gas operation - operates on AC mode
Operation
LP Gas
Manual Gas Valve
Igniter
High Voltage Cable
Electrode
Solenoid
Wiring
Lower Circuit Board
5.
Insufficient cooling on all modes.
Ventilation
Leveling
Ambient Temperature
Air Leaks
Thermistor
Cooling Unit
6.
Insufficient cooling on AC - cools properly on
gas mode.
AC Volts
Heating Element
Lower Circuit Board
SYMPTOM
7.
Insufficient cooling on Gas - cools properly on
AC mode.
CAUSE
LP Gas
Orifice
Flue Baffle
Flue Tube
Burner
Lower Circuit Board
Freezes.
Operation
Thermistor
Lower Circuit Board
9. Check light on.
DC Volts
Wiring
LP Gas
Manual Gas Valve
Solenoid
Orifice
Burner
Thermocouple
Lower circuit Board
10.
Interior light on when door is closed.
Wiring
Door Switch
Door Position
11.
Rapid formation of frost.
Food Storage
Interior Liner to Frame
High Humidity
Air Leaks
8.
12. Water on frame.
Interior Liner to Frame
High Humidity
Air Leaks
Climate Control Heater
DISPLAY PANEL
(RM2652, RM2852)
LEGEND 2-WAY MODEL
1.
2.
Main Power Button ON/OFF
AUTO/MANUAL Mode Selector Button
A. AUTO Mode indicator lamp
B. CHECK indicator lamp (Gas Mode Only)
C. Climate control switch
A
B
..
a ON
(IIfzl
m
= OFF
/
o CHECK
AUTO\0
MANUAL
81
Dometic
REFRIGERATOR CONTROL
LEGEND
DISPLAY PANEL
(RM2612, RM2812)
1. Main Power Button ON/OFF
2. AUTO/MANUAL Mode Selector Button
A. AUTO Mode indicator Lamp
B. CHECK Indicator Lamp
(GAS Mode Only)
C. Climate Control Switch
3
START-UP INSTRUCTIONS
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 automatically select the most suitable
energy source which is available, either 120 Volt AC or LP gas operation. The refrigerator can be
operated in either the AUTO mode (thermostat factory preset below the safe food storage temperature)
or MANUAL mode (continuous operation - no thermostat control).
NOTE: Under certain cool weather conditions, the food in the lower portion of the fresh food compartment
may freeze if operated for an extended period of time on the MANUAL mode.
A.
B.
C.
A 12 volt DC supply must be available for the electronic control to function. The refrigerator will work
down to 9.6 volt DC.
B. Press the main power ON/OFF button (1) to the DOWN position.
In AUTO mode operation, the temperature is controlled by a single temperature setting, on the energy
source selected by the control system. (See Auto Mode)
In MANUAL mode operation, the refrigerator will run continuously on the energy source selected by the
control system. (See Manual Mode)
NOTE: The food in the lower compartment may be frozen if the refrigerator is left on MANUAL mode.
TO SHUT OFF THE REFRIGERATOR
The refrigerator may be shut off while in any mode of operation by pressing the main power ON/OFF
button to the UP (OFF) position. This shuts off all DC power to the refrigerator, including the interior
light.
OPERATING MODES
AUTO MODE
Press the AUTO/MANUAL mode selector button (2) to the DOWN position. The AUTO mode indicator lamp
(A) will illuminate.
When operating in the AUTO mode, the AUTO mode indicator lamp (A) will illuminate. The control system
will automatically select between AC and GAS operation with AC having priority over GAS. If the control
system is operating on AC energy and it then becomes unavailable, the system will automatically switch to
GAS. As soon as AC becomes available again the control will switch back to AC operation.
If 120 volts AC is not available, the control system will automatically switch to GAS operation. Within 45
seconds the burner should be ignited and operating normally. If unsuccessful, the CHECK indicator lamp (B)
will illuminate.
To restart an ignition attempt with the CHECK lamp illuminated or to clear (turn off) the CHECK lamp, press
the main power ON/OFF button to the OFF and then to the ON position. The control system will attempt a
new 45 second ignition sequence.
On the initial refrigerator start-up on gas (120 volts AC is not available), it may take longer than 45 seconds
to allow air to be purged from the gas line. 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 may require
resetting the main power ON/OFF button (1) three of four 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 all manual shutoff valves in
the lines are open.
NOTE: DO NOT continue to reset GAS operation if the CHECK indicator lamp continues to be illuminated
after 3 or 4 tries.
If 120 volts AC becomes available while the CHECK indicator lamp is on, the control system will switch to
120 volt AC operation, The CHECK lamp will not turn off until the main power ON/OFF button is pressed to
the OFF then ON position.
In AUTO mode operation, the temperature is controlled by a single temperature setting.
MANUAL MODE
When operating in the MANUAL mode, the AUTO mode indicator lamp (A) will be off, and the refrigerator
will run continuously on the energy source selected by the control system.
NOTE: The food in the lower compartment may be frozen if the refrigerator is left on “MANUAL” mode.
..
STANDBY MODE
This control system contains a feature that will continue to operate the cooling system in the event of a failure
of a major operating component. If the control cannot read the temperature sensor and operate at the preset
temperature, then the control will run the cooling unit like the MANUAL mode.
The refrigerator will continue to operate in this mode indefinitely or until a new sensor is installed and the
system is reset.
AC VOLTAGE REQUIREMENTS
The proper operating range is 100 to 132 volts. If voltage drops below 100 volts, cooling efficiency will
decrease with voltage decrease. The refrigerator will not switch to another mode of operation until all
AC power is lost.
The refrigerator is equipped with a three-prong (grounded) plug for protection against shock hazards, and
should be plugged directly into a properly grounded three-prong receptacle.
12 Volt AC
120 Volt AC
Receptacle
COMPONENTSHEATING ELEMENT
Remove the heater leads from the lower circuit board and measure for proper resistance across the
two leads.
You should obtain the following readings, *lo%:
WATTS
VOLTS
OHMS
RM2612
295
120
48
RM2652
325
120
44
RM2812
325
120
44
RM2852
325
120
44
DC VOLTAGE REQUIREMENTS
Clean Direct Current (DC) power is mandatory for high-tech circuits to operate as designed.
A battery will provide straight line DC power.
The converter and alternator produce DC power by a series of diodes that rectify alternating current
to DC.
AC ripple can be measured by a digital voltmeter set on the AC scale at the main terminal block
connections. Six volts AC or less is acceptable.
MAIN TERMINAL BLOCK
The operational range of the unit is a minimum of 9.6V DC to a maximum of 22V DC. At 22V DC, the
unit will automatically shut down until voltage has decreased to 18V DC for proper operation; however,
the panel lights will continue to illuminate until voltage has dropped to 4V DC or below.
Do not use the body or chassis of the RV as a substitute for either or the two conductors. Proper
polarity is crucial for refrigerator operation.
Power Module Cover
Flexible Cord
lniet Fitting
Power
Module
Cover -
Shutoff Valve
DC COMPONENTS
THERMISTOR
Disconnect the thermistor harness from the P2,
2-pin terminal on the lower circuit board. Place
the thermistor in a glass of ice water, approximately 33°F to 35°F. Wait 2 to 3 minutes. You
should get a reading of approximately 7,000 to
10,000 ohms.
[email protected]
cB
1
lhetmistor
unplug ed
frcfn 2
Board
7
SOLENOID VALVE
Check the solenoid coil with a properly calibrated ohm meter. Remove the connector from the solenoid
and measure the resistance across the terminals. The proper reading would be 49 ohms with tolerance
range of ten percent.
..
Next, hook up a manometer at the test port. Then check for DC volts at gas valve terminals while the
unit is in trial-for-ianition. If DC volts are present and pressure is low, replace the valve. If DC volts are
not present at the valve while the unit is in trial-for-ianition, verify that the wire at Plug 3, Terminal 2 on
lower circuit board have DC volts (9 or more).
RM2612 & RM2612
RM2652 & RM2652
IGNITER
First verify proper voltage at the positive (+) and ground (-) terminals of
the ignitor. The reading should be within one volt of incoming voltage at
the main terminal block during trial-for-ianition
Next, remove high voltage cable from igniter. The igniter should produce a sparking sound, during trial-for-ianition. If not, replace the
igniter.
The igniter installed on the refrigerators as original equipment is part
number 2931132019 (RV Gas Model 679). This igniter is rated 50 MA.
This igniter may also be used on any other model.
DO NOT install the Channel Mark 6, Model 12E igniter (shown below) as a service replacement part.
MARK 6, MODEL 12E
W/O 1282150 9318
12VDC
25mA
CHANNEL PRODUCTS
CHESTERLAND OH 44026
Installation of the Channel Products, Inc., Gasliter Mark 6, Model 12E, will VOID the Warranty on the
refrigerator.
HIGH VOLTAGE CABLE
Disconnect high voltage cable from electrode. If sparking starts during trial-for-ianition, the cable is
good. If there is no sparking during trial-for-ianition ' disconnect high voltage cable at the igniter. If
there is a sparking sound from the igniter during trial-for-ianition, then replace high voltage cable.
ELECTRODE
Do a visual check for cracks or breaks on the ceramic insulator. The spark gap must be set at three
sixteenths (3/16”) of an inch and tip of electrode above the slots in the burner.
BUR
..
UPPER CIRCUIT BOARD
NOTE: The PAL tester will allow for proper testing of the integrity of the upper and lower circuit boards.
PAL is available from your Dometic parts distributor.
With main ON/OFF switch on display panel in OFF position:
Check for DC voltage at Plug 1, Terminal 4 (orange wire) and terminal 5 (red wire) negative (-) DC on
the lower circuit board. If no voltage, then check fuse condition. Check for DC voltage between J4
and J10 terminals on the lower circuit board.
Green,
,
Next, check for DC voltage at the upper circuit board between terminal 4 (orange wire) and terminal 3
(red wire) which is negative (-) DC. If no voltage, and your previous check proved voltage at the lower
circuit board between these wires, replace the cable assembly.
With main ON/OFF switch on display panel in ON position:
Check for DC volts between terminal 3, red wire (-) negative and terminal 5 (green wire) and
terminal 1 (black wire). If there is no voltage, the ON/OFF switch on upper circuit board is defective.
Next, do the same voltage test at the lower circuit board. Red wire (-) negative plug 1, terminal 5, to
green wire, plug 1, terminal 1 and black wire, plug 1, terminal 3. If there is no voltage and you had
voltage on previous test, the cable assembly is defective.
LOWER CIRCUIT BOARD
The controls for Models RM2612, RM2812, RM2652 and RM2852 are unique to these models. They
are NOT interchangeable with any other models.
If you suspect mismatched part numbers, compare the part numbers on parts to the ones listed below
to ensure a proper match.
The RM2612 with Serial Number 41900000 or higher will have Version III controls as original
equipment.
The RM2812, RM2652 and RM2852 should have only Version Ill controls as original equipment.
VERSION I
Display Panel
Power Module
Thermistor
2932189.01
2931842.02 or 2931842.03
2931863035
VERSION II
Display Panel
Power Module
Thermistor
2932189.02
2931842.02X
2931863035
*
Power Module has red plugs and a Red Dot on
the cover.
Power Module
2931842.02X
Red
VERSION Ill
Display Panel
Power Module
Thermistor
10
2932189.03
2931842.04
2931863035
Power Module
2931842.04
A. DC VOLT: ALL TESTS ARE TO BE DONE WITH THE REFRIGERATOR IN THE COOLING MODE.
Measure volts between terminal J4 and the ground strip.
B. AC MODE: Check that incoming AC voltage is present at terminals J5 and J6 on the circuit board.
Check for voltage at the heating element connection terminals J7 and J8 on the circuit board. If no
voltage is present, check the 5 amp AC and 3 amp DC fuses.
r
“. GAS MODE: First, check for voltage during trial-for-ignition at Plug 3, Terminals 1 (white wire) and
2 (yellow wire) to the solenoid. If no voltage is present, change the circuit board. If voltage is present,
check for voltage at the solenoid.
Check for voltage to the igniter. If no voltage is present, check the wires. If good, then change the
circuit board.
If flame extinguishes during the cooling mode, the circuit board will not supply voltage to Plug 3,
Terminal 4 (blue wire) until the millivolts have decreased to 10*3.
To check the flame sense circuit of the lower circuit board, measure the millivolts between J3 terminal and the other wire connection from the thermocouple. The millivolt meter should read between 25
to 35 millivolts with the gas flame burning. Turn the manual shutoff valve to OFF and watch the
millivolt reading as it drops. Note the millivolt reading when Plug 3, terminal 4 (blue wire) receives
power. It should be lo*3 millivolts or 7 to 13.
DOOR SWITCH (Only on Models Equipped with Interior Lights)
When the switch arm is depressed, there should not be continuity. When the switch arm is NOT depressed, there should be continuity.
FUSES
The 3 amp DC fuse is designed to protect the circuit board from internal shorts. The 5 amp AC fuse
is designed to protect the integrity of the AC heater circuit from shorts.
11
CLIMATE CONTROL HEATER
To check the switch, disconnect the wires and do a continuity check. In the OFF position, there should
be no continuity. In the ON position, there should be a continuity reading.
To check the heater itself, do an ohms resistance reading on the heater wire by using a properly
calibrated ohm meter. The proper ohms reading is 24 ohms f 10%. The approximate amp draw is less
than .5 (1/2) amp.
LP GAS REQUIREMENTS
The LP gas pressure to the refrigerator should be 11 inches water column with half of all BTU’s of the
RV turned on. With all other appliances off, the pressure to the refrigerator should not exceed 12
inches water column. To check the gas pressure when the refrigerator is operating, there is a pressure
..
test port on the solenoid.
RM2612 & RM2812
Power
Module
Cover
- liizA_
(12Volt
Manual Gas
T erminal
l
Block
Shutoff Valve
Flexible Cord
Inlet Fitting
Burner Jet
w
RM2652 & RM2852
12
SECTION 7
LP GAS COMPONENTS
MANUAL GAS SHUTOFF VALVE
To check the shutoff valve, remove and inspect for any obstructions.
Gas
Connection
Manual Gas
Shutoff Valve
Shown in “ON”
position)
RM2652 & RM2852
n
Gas Connection
\
fl
nl
Manual Gas Shutoff
Valve (Shown in “ON” Position)
Pressure Test
Port
Orifice
ORIFICE
The orifice is cleaned by using an alcohol based solvent and allowing to air dry.
If there is a lack of cooling on gas operation, verify the orifice is the proper size per the chart below:
RM2612
RM2812
RM2652
RM2852
#53
#58
#58
#58
13
..
THERMOCOUPLE
The thermocouple should produce 25 to 35 millivolts when connected to the lower circuit board. Any
reading below 18 millivolts could cause erratic gas operation.
BURNER
The burner should be cleaned periodically, at least once a year. Soak the burner in an alcohol-based
solvent and allow to air dry.
FLUE BAFFLE
At least once a year, clean and check for any damage.
The proper position of the baffle above the burner should be as follows:
RM2612
1-5/8"
1-3/4"
RM2812
RM2652
1-7/8"
1-7/8"
RM2852
FLUE TUBE
The flue tube must be cleaned periodically. Remove flue cap and flue baffle, then cover the burner and
clean by using a flue brush, Dometic Part No. 0151404001,
WIRING
EXTERNAL WIRING
A. 120 volts AC Connection
The refrigerator is equipped with a three-prong (grounded) plug for protection against shock hazards
and should be plugged directly into a properly grounded three-prong receptacle.
B. 12 Volt DC Connection
The 12 volt DC supply circuit must be fused, and the maximum fuse size is 5 amps.
DO NOT use the chassis or vehicle frame as one of the conductors,
Clean Direct Current (DC) power is mandatory for high-tech circuits to operate as designed.
A battery will provide straight line DC power.
The converter and alternator produces DC power by a series‘of diodes that rectify alternating
current to DC.
INTERNAL WIRING
Verify the refrigerator is wired per the wiring diagram for the exact model you are working on. See the
following typical wiring diagram.
14
@-BURNER H O U S I N G
@--PROTECTIVE
@-CICCUI~ BOARD DISPLAY
@-CIRCUIT BOARD POWER
@--ELECTRODE
@ F U S E 3A
@-FUSE 5A
@ H E A T E R 120V A C
-HEATING CABLE
@LIGHT
&K%:~"
[email protected] VALVE
*SWITCH
@-SWITCH LIG H T
*TERMINAL BLOCK
@ - TE S T P O I NT
@-THERMISTOR
QTHERMJCOUPLE
@CHASSISGROUND
EARTH
LEVELING
The absorption design utilizes no mechanical pumps or compressors to circulate the refrigerant within
the system, so proper leveling must be maintained to provide the correct refrigerant flow. Without
proper leveling refrigerant within the cooling unit will collect and stagnate at certain areas. Refrigerators
have a type of cooling unit that utilizes an enclosed pump tube. To ensure proper leveling, the vehicle
needs to be leveled so it is comfortable to live in. When the vehicle is moving, leveling is not critical
as the rolling and pitching movement of the vehicle will pass to either side of level, keeping the refrigerant from accumulating in the piping.
VENTILATION
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. There should be as little open space as
possible surrounding the sides and top of the refrigerator to
achieve proper air flow.
NOTE: Refrigerators should be installed in accordance with
appropriate installation instructions received with the
refrigerator.
0” CLEARANCE
FROM SIDE AND
CLEARANCE
FROM
COMBUSTIBLE
MATERIALS
PATH OF
AIR LEAKS
Check the gasket on the doors to be sure of a positive air seal. Close the door on a dollar bill, then pull
the dollar bill out. If a gasket is not sealing properly, warm the gasket material with a hair drier.
Close the door and the magnetic strip should pull the gasket to the metal frame. Check that the cooling
unit is installed properly.
MODELS RM2612 & RM2812:
The refrigerator is secured in the enclosure with six screws and they must be installed in the following
order:
First Two Screws installed on front base;
Second Two Screws installed in the top frame;
Third Two Screws installed in the rear base.
MODELS RM2652 & RM2852:
CONDENSATE WATER DRAIN HOSE: A 3/4”
hole must be drilled through the flooring in the
opening of the base plate on the rear of refrigerator. Seal around the hose where it goes through
the hole.
The refrigerator is secured in the enclosure with
six screws. They must be installed in the following order:
First: Two screws are installed in front
decoration strip and through the front
base.
A. The front strip is to be installed after
the refrigerator is set into the alcove.
B. Install the lower front strip by sliding it
under the bottom hinge plate as
shown.
16
C. When the front strip is in place, install one screw through the hinge and into the floor. The second
screw is installed with a washer on the opposite side.
Second: Install the two screws in the top frame.
A.The top decoration panel must be removed from the refrigerator before the screws can be
installed. Open refrigerator door and gently push the tabs out of the hole in the hinge with flat blade
screwdriver.
B. Carefully tilt the top decoration panel and lift up to remove from top frame.
C. Install the second two screws in the top frame as shown.
17
D. Replace the top decoration panel.
Third: Two screws installed as shown in rear base.
DOOR POSITION
The door position can be checked by observing any misalignment of the door in relation to the frame.
Loosen the hinge bracket screws, reposition the door then tighten the hinge bracket screws.
To adjust up or down, add or remove washers from the lower hinge pin.
AMBIENT TEMPERATURE
As the ambient temperature increases, the air temperature in the area of the cooling unit increases.
The double door refrigerators should maintain approximately 43 degrees food storage temperature at 110 degree ambient temperature.
COOLING UNIT
The cooling unit is a self-contained, hermetically sealed set of coils where the refrigeration process
takes place. The chemicals involved in the cooling process include hydrogen, ammonia, water and a
rust inhibiting agent. There are no repairs recommended on the cooling unit.
18
To check the cooling unit, first verify the AC heating element is good. Then place approximately one
gallon of water inside the refrigerator and place a thermometer in one of the containers of water.
Supply 115 volts direct to the AC heating element and operate for at least 12 hours. Check the temperature on the thermometer. It should be at 45 degrees or lower depending on test conditions.
FOOD STORAGE
It is essential that the shelves are not covered with paper or large storage containers.
Odorous or highly flavored foods should always be stored in covered dishes, plastic bags or wrapped in
foil or waxed paper to prevent food odors. Vegetables, lettuce, etc., should be covered to retain their
crispness. NEVER PUT HOT FOOD INTO THE REFRIGERATOR.
..
HIGH HUMIDITY
Condensation may actually run off the frame. As the humidity is reduced, the “sweating” will decrease. High humidity can also be a factor in rapid formation of frost.
INTERIOR LINER SEAL TO FRAME
Condensation could form on the frame. Apply a small bead of silicone all the way around the perimeter
where the frame meets the interior liner.
Slide the refrigerator out approximately 2-4 inches. Apply a foil-backed adhesive tape to the joint
between outer frame and foil-backed refrigerator insulation.
Use a clear silicon caulking compound and seal
the seam between the refrigerator’s plastic liner
and the metal frame.
NOTE: TO FORM A PROPER SEAL, IT IS
IMPORTANT NOT TO LEAVE ANY GAPS.
fXJL&l$AM
PLASTIC LINER
%i!iETAL
19
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