3
DIAGNOSTIC SERVICE MANUAL
Dometic
®
RM2604/2804
Refrigerators
SECTION 1
AC VOLTAGE REQUIREMENTS
The refrigerator is a 120-volt AC, 60 Hz appliance. The
proper operating range is 100 to 132 volts. Check the
AC volts at the receptacle where the refrigerator is
attached. Voltage is outside of the proper operating
range, correct the power source problem.
SECTION 2
AC COMPONENTS
2.1 HEATING ELEMENT
The heating element is
designed to deliver a
predetermined amount of
heat to the cooling unit.
To check a heating
element, remove the
heater leads from the
terminal block and
measure for proper
resistance across the
two leads with a properly
calibrated ohm meter. This check is to be done with the
heating element at room temperature. The proper ohms
for RM2604 is 48 and RM2804 is 44 with a tolerance of
ten percent. If the resistance is outside the tolerance
range, replace the heating element.
2.2 THERMOSTAT
It is an electric only thermostat. On 2-way models it
controls the AC heating element. On 3-way models it
controls the DC heating element as well as the AC
heating element. The thermostat regulates the cabinet
temperature by making and breaking the heat source
circuit. The internal mechanism breaks contact (continu-
ity) when adequate cabinet temperature has been
reached. Check the thermostat for continuity or use a
jumper wire with insulated clips and bypass the thermo-
stat.
NOTE: Care should be used. Do not short to thermostat
casing. Also remove the jumper after testing is com-
pleted.
If the above test allows the refrigerator to operate,
replace the thermostat.
SECTION 3
DC VOLTAGE REQUIREMENTS
For the refrigerator to operate the interior light, igniter
(gas mode) and DC volt operation (3-way models only),
DC voltage must be supplied to the terminal block or
blocks (2 terminal blocks on 3-way models) at the rear of
the refrigerator. The operational range is 10.5 to 15 volts
DC. Connecting the refrigerator to an unregulated
converter can result in improper operation of the refrig-
erator. Check for proper voltage at the terminal block or
blocks at the back of the refrigerator. If power is outside
the operational range, correct the power supply problem.
The power supply to the refrigerator must be fused. The
interior light and igniter must be on a separate circuit and
will draw about 1 amp at 12 volts DC. The DC heating
element (on 3-way models only) will draw 18 amps at 12
volts DC. The maximum fuse size is 25 amps for the
RM2604 and RM2804.
SECTION 4
DC COMPONENTS
4.1 SWITCH
This is the switch that selects the mode of operation
(120 volt AC, gas and 12 volt DC). It is also a circuit
interrupter for each mode of operation on the refrigera-
tor. When the customer selects either AC, gas or DC (3-
way models only) operation, the selector switch directs
electricity first to the interior light and the thermostat and
on to the heating element or the igniter for gas mode.
When this switch is turned off, the AC or DC circuit is
interrupted. To check the switch in the AC mode,
continuity should exist between these terminals: 1 to 1A,
2 to 2A and 7 to 7A. To check the switch in the gas
mode, continuity should exist between these terminals: 4
to 4A and 7 to 7A.
To check the switch in the DC mode (on 3-way models
only), continuity should exist between these terminals: 5
to 5A, 6 to 6A and 7 to 7A.
NOTE: To do a continuity check, first be sure all power
is disconnected or off to the refrigerator. Second,
remove all wires from the switch. After the check, be
MANUAL GA S
SHUTOFF VA LVE
TERMINAL BL OCKS
3-WAY ONL Y
ALL UNIT S
3 P RONG P LUG
FOR 120V A C
COVER
12 V olts
DC
Heater
12 V olts
DC
Reigniter
Lamp
