Dc Components; Thermistor; Solenoid Valve; Igniter - Dometic RM 3762 Service Manual

SectIon 5 dc comPonentS

5.1 thermistor

Disconnect the thermistor harness from the P2, 2-pin ter-
minal on the lower circuit board. Place the thermistor in
a glass of ice water (more ice than water), approximately
33° F to 35° F. Wait 8 to 10 minutes. You should get a
reading of approximately 8,000 to 10,000 ohms. Always
test from the wire side as shown below as not to create a
connection problem at the P2 connector.
5.2 Solenoid
Check the solenoid coil with a properly calibrated ohm
meter. Remove the connectors from the solenoid and
measure the resistance across the terminals. The proper
reading would be 49 ohms with tolerance range of ten
percent. Failure of the solenoid is very unlikely. Next,
hook up a manometer at the test port. Then check for DC
volts at gas valve terminals (Yellow + White -) while the
unit is in trial-for-ignition. If DC volts are present and pres-
sure is low, replace the valve. If DC volts are not present
at the valve while the unit is in trial-for-ignition, verify that
the wire at Plug 3, Terminal 2 on lower circuit board has
DC volts (9 or more).
Thermistor
unplugged
from PC board

5.3 Igniter

The igniter used on Dometic model refrigerators, oper-
ates on 12 volt DC. 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 re-
sistance 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. The resistance is monitored by the igniter, and,
if for any reason the flame goes out, the igniter begins
sparking until the burner is lit. The resistance between the
electrode and burner drops and the igniter stops sparking.
this is an energized circuit. Shock can occur
if not tested properly. testing is to be done
by a qualified service technician.
This insures that the flame will always be lit when de-
sired. First verify proper voltage at the positive (Yellow
+) and ground (Black –) terminals of the igniter. The read-
ing should be within 1.5 volt of incoming voltage at the
main terminal block during trial-for-ignition. Next, remove
high voltage cable from igniter. The igniter should pro-
duce a sparking sound during trial-for-ignition. If not, re-
place the igniter. While operation is in the gas mode, the
power module and igniter are constantly monitoring the
presence of flame. If the flame is blown out, the reignitor
will immediately start sparking. When the power module
senses the loss of flame (thermocouple voltage below 13-
MVDC) the 45 seconds trial for ignition period is started.
The igniter installed on the refrigerators as original equip-
ment is part number 2931132019 (RV Gas Model 679).
This igniter is rated 50 MA. This igniter may also be used
on any other model. When replacing the igniter always
provide the product number for proper replacement. do
not install the Channel Mark 6, Model 12 E igniter (as
shown) as a service replacement part. Installation of the
Channel Products, Inc., Gasliter Mark 6, Model 12 E, will
VOID the Warranty on the refrigerator. The Dometic refer
could use a few different igniters. To acquire the proper
igniter always provide the product number.
11