Orifice; Thermocouple - Dometic RM1350 Diagnostic Service Manual

AUTO mode lamp is lit and LP mode lamp is flashing.
Indicates temporary gas operation lockout.
5. Remove protection cover from burner and open the
manual gas shutoff valve. Do not change any button posi-
tions on the control panel. Apply a non-corrosive commer-
cial bubble solution to the burner jet orifice.
6. No bubbles should appear at the opening of the burner
jet orifice. The presence of bubbles indicates a defective
gas safety shutoff, and service is required.
7. If no bubbles were present at the burner jet orifice, it
should be rinsed with fresh water. Be careful not to dam-
age the burner jet orifice. Replace cover and press the
main power ON/OFF button OFF and back ON. Normal
operation of the burner should return. Allow the burner to
operate for a minimum of five minutes.

8.2 Orifice

The Dometic orifice is a brass alloy with a man-made ruby
pressed in the center that has been laser-beam drilled in
a spiral pattern. The orifice is cleaned by using an alcohol
based solvent. Soak the orifice for approximately 1 hour
and allow to air dry. Don't insert anything in the center of
the orifice because it will harm the man-made ruby. Do
not use an air nozzle to blow thru the orifice as the ruby
could be moved. Never over or under size the orifice on a
Dometic refrigerator. The cooling unit is designed to work
with a predetermined amount of heat and modifying the
orifice size will decrease cooling. If there is a lack of cool-
ing on gas operation, verify the orifice is the proper size
per the chart.
do not use a wire or pin when cleaning the burner
jet as damage can occur to the precision opening.
this can cause damage to the refrigerator or create
a fire hazard.
MODEL
RM1350
Always check the parts list with the model and product
number to assure the right jet size.

8.3 thermocouple

The Thermocouple is a component that extends over the
burner assembly so its tip is in the path of the flame. Dur-
ing normal gas operation, the thermocouple should pro-
duce 25 to 35 millivolts DC when connected to the lower
circuit board. Any reading below 20 millivolts DC could
cause erratic gas operation. note: A reading of 20 or
less could be caused by low gas pressure, carbon build
up or improper thermocouple location. The thermocou-
ple should be centered over the burner and extend over
3 slots. The control board reads negative millivolts DC
from the thermocouple and the positive lead goes to the
ground terminal on the control board. The lower control
has built-in delay when the unit is first turned on. If the
lower control reads millivolts in excess of 6 MVDC the
control will go into a 30 second gas delay before attempt-
ing to light on gas. To test the thermocouple set the meter
to DC millivolts. Put the black lead from the meter to ter-
minal J4 and the red lead from the meter to J10 or ground
(other lead from thermocouple). Start the unit on gas and
measure the DC millivolts produced by the thermocouple.
The thermocouple should produce 22 to 36 millivolts DC
within 45 seconds. If the millivolts are 20 or below erratic
operation will occur. Anything below 10 to 13 the control
board will not keep the gas valve energized and turn on
the check light after the third trial-for-ignition. Approx 6 to
7 minutes.
31
JET SIZE
#76