Operation; Control Description; Auto Mode; Gas Mode - Norcold 600 Repair Manual

Control Description

These refrigerator models require
12 volts DC be applied at all times
in order for the refrigerator to oper-
ate in any mode. The 12 volts must
be supplied to the Power Supply
terminal J3 ground and J4 + 12
volts. From terminal J4 the 12 volts
is routed through a 3 AMP fuse to
a wire harness (on 3 way models
the 12 volts from J4 is also routed
thru a 20 fuse to the normally open
contact of relay K3).
On the single door refrigerator,
when the Mode Selector switch(s)
is in the OFF position all current
draw is eliminated.
On double door models, the 12
volts is controlled by the User at
the Humidity/Storage switch which
is located on the Mode Selector
(Eyebrow). When the switch is in
STORAGE position, all DC current
draw is eliminated. In the NORMAL
position, the switch allows normal
operation but restrains operation
of the Humidity heater. The HIGH
HUMIDITY position allows both
normal operation and the Humidity
heater function.
By setting the HUMIDITY/STOR-
AGE switch to the NORMAL op-
eration or HIGH HUMIDITY posi-
tion, the 12 volts is then applied
thru the switch back to the Power
Supply where it is applied to the
emitter of transistor Q2, the coil
of relay K1, then thru the cable to
the Mode Selector switch on the
Eyebrow board. When the Mode
Selector is set to any mode cur-
rent will flow thru transistor Q2,
thru the cable, to the indicator
lights on the Eyebrow board.

Operation

Auto Mode

When AUTO is selected, and 120 volts AC is supplied to terminals J9 hot,
and J8 neutral the AC light on the Eyebrow will be illuminated. The 12 volts
DC will now be pulled to ground thru a transistor on the Eyebrow board, re-
lay K1's contact will close and 120 volts AC will be applied to the AC heater
terminals, J6 and J7 on the Power Supply.
If the 120 volts AC input is disconnected from the Power Supply input ter-
minals J8 and J9, the opto coupler on the Power Supply will sense the loss
of 120 volts. Q1 transistor will now ground the coil on relay K2, K2 contact
will close, which breaks the 12 volt circuit to relay K1, and 12 volts will be
applied to the Ignition Module to start the ignition sequence, and the L.P.
light on the Eyebrow will illuminate.
When the 120 volt AC is reapplied to the Power Supply terminals J8 and J9
the refrigerator will automatically switch back to AC operation by the reverse
of the previous paragraph.

Gas Mode

When the Mode Selector switch is set to GAS, the L.P. light on the Eye-
brow will illuminate, the coil of relay K2 will be grounded by a transistor on
the Eyebrow board, K2 contact will close, and 12 volts will be applied to the
Ignition Module to start the ignition sequence, the Gas Solenoid valve will
open. The ignition electrode will spark the Burner. When a flame is sensed
the spark will cease. If the Burner does not light, the electrode will not sense
the flame, the spark will cease. In this case, the Gas Solenoid valve will
close, and the Ignition Module will illuminate the check light on the Eyebrow.
DC Mode
When the Mode Selector is set to DC ON (3 way models only), the coil
of relay K3 is grounded by a transistor on the Eyebrow board, relay K3
contact closes and 12 volts DC is applied to the DC heater terminal J5 on
the Power Supply.
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