Background Operations - Norcold N611V SERIES Service Manual

Theory of Operation - Auto AC and LP Gas Mode - cont'd.
Auto LP Gas Mode
When operating in the Auto LP Gas mode the power board
measures the thermistor value and communicates it to the
optical display board. The thermistor, a temperature device
whose internal resistance goes down as the temperature goes
up, is connected to the power board via terminals P2-1 and
P2-6. The optical display board compares the actual thermistor
value to the factory preset cut-in and cut-out temperature
values. Should the thermistor value fall below the cut-in
value, the optical display board simultaneously requests the
power board to turn ON gas valve relay (K1) and high voltage
transformer (T1) outputs.
Anytime relay K1 is turned ON, 12VDC passes through the
now closed K1 contacts to terminal P1-10 of the power board
and out to the gas valve solenoid, energizing the gas valve.
With the gas valve energized, LP gas fl ows to the burner
tube. Simultaneously, energy pulses from the high voltage
transformer (T1) are carried out to the burner via the spark
sense electrode wire. As the energy pulses reach the end of
the electrode they jump across the gap between the electrode
and the burner creating sparks. The sparks ignite the LP gas
and a fl ame is established.
Via the fl ame rectifi cation process a signal is then sent back to
the power board through the spark sense electrode wire letting
the power board know there is a fl ame present. Knowing
a fl ame is present; the power board deactivates the spark
output. At the same time; the power board communicates to
the display letting it know a fl ame is now present.
When the thermistor value reaches a particular cut-out value
the optical display will request the power board to turn OFF the
gas valve output, allowing the fl ame to extinguish. If for some
reason the fl ame goes away while there is a call for cooling,
the power board will turn the high voltage transformer back
on and attempt to re-ignite the propane. For safety reasons
the sparking at the burner (trial for ignition time) will last a
maximum of 30 seconds, at which time the gas valve/high
voltage transformer outputs will be turned off and the LP Gas
mode will be locked out.
The electronic controls will automatically default back to the
Auto AC mode and wait, indefi nitely, for AC voltage to return.
The optical display board will display:
• Solid RED power indicator light
10
N611v, N811v Models

Background Operations

Interior Light / Door Switch
The interior-light/door switch is a normally open reed switch
that is an integral component of the optical display board.
Theory of Operation - Interior Light / Door Switch
The magnetic pull from a permanent magnet located
underneath the top door trim maintains the reed switch
(N) contacts closed (light off) when the door is fully closed.
Opening the door breaks the magnetic pull, which in turn
causes the reed switch contacts to open (light on). The optical
display board senses the reed switch contacts are open and in
turn:
• Requests that the power board turn ON the K4
relay. Anytime relay K4 on the power board is
turned ON, 12VDC passes through the now closed
K4 contacts to terminal P1-7 of the power board
and out to the interior light.
• Initiates a 2-minute timer that once timed out
requests the power board to turn off the K4 relay.
This prevents the interior light from being left on in
the event the door is not completely shut.
Anytime the door is sensed open the divider heater
output will be turned off.
Interior Light Test Procedure:
• Place a magnetic tipped screwdriver or small magnet
beneath the optical control
• Move the magnetic tipped screwdriver from side-to-side
as shown below
Verify:
• The interior light turns ON-OFF as the magnet is passed
below the optical control
• Contact Customer Service for further instructions.
www.norcold.com/cda
NOTE
Art02410
Interior Light Test
Refrigerator Service Manual
064