Norcold N620 User manual

Service Manual
For models N620 and N621: 6 cu.ft., 2-way, R.V. refrigerators.
For models N640 and N641: 6 cu.ft., 2-way or 3-way, R.V. refrigerators.
For models N640-IM and N641-IM: 6 cu.ft., 2 way or 3-way, R.V. refrigerators with ice maker.
For models N820 and N821: 8 cu.ft., 2-way, R.V. refrigerators.
For models N840 and N841: 8 cu.ft., 2-way or 3-way, R.V. refrigerators.
For models N840-IM and N841-IM: 8 cu.ft., 2-way or 3-way, R.V. refrigerators with ice maker.
These model numbers are 2-way refrigerators. The model numbers of 3-way refrigerators
include “.3”.
NORCOLD, Inc.
P.O. Box 4248
Sidney, OH 45365-4248
Part No. 619394 (5-98)

Service Manual 2
Table of Contents
Safety Awareness
Safety Instructions
Introduction ..............................................................................2
Safety Awareness....................................................................2
Safety Instructions ...................................................................2
Specifications ..........................................................................3
Supply Voltage, Fuse, and Wire Size Requirements ..............3
Operating Requirements ........................................................4
Heater Specifications .............................................................. 4
Other Current Draws ............................................................... 4
Ventilation Requirements........................................................5
Propane Gas Components.....................................................5
Examine the Gas Supply System for Leaks ....................5
Electrical Components............................................................6
Operating the Refrigerator Controls (models N620, N621,
N820, and N821).............................................................. 6
Operating the Refrigerator Controls (models N640, N641,
N640-IM, N641-IM, N840, N841,N840-IM,and N841-IM) .8
Backup Operating System ......................................................9
Fault Codes (models N620, N621, N820, and N821)..........10
Fault Codes (models N640, N641, N640-IM, N641-IM, N840,.
N841,N840-IM,and N841-IM) ......................................... 11
Troubleshooting ....................................................................12
No Display on Display Panel .........................................12
Propane Gas ignition Failure.........................................13
Fresh Food Compartment Door Ajar .............................14
AC Power Not Available .................................................14
AC Voltage Too Low .......................................................15
AC Voltage Too High.......................................................15
DC Voltage Too Low .......................................................15
DC Voltage Too High ......................................................16
AC Heater Output Failure ...............................................16
DC Heater Output Failure ..............................................16
DC Heater Failed Open .................................................17
AC Heater Failed Open ..................................................17
Flame Sense Circuit Failure ..........................................18
Back Up Operating System............................................18
Control Diagnostic Function (models N620, N621,
N820, and N821)............................................................19
Control Diagnostic function (models N640, N641, N640-IM,
N641-IM, N840, N841,N840-IM,and N841-IM)...............20
Ice Maker (models N640-IM, N641-IM, N840-IM
and N841-IM)..................................................................21
Ice Maker Specifications ................................................21
Common Problems and Solutions ...............................22
Trouble Shooting............................................................22
Ice Maker Does Not Make Ice ........................................23
Refrigerator Maintenance......................................................24
Gas Flame Appearance .................................................24
Remove and Clean the Burner Orifice...........................24
Diagnosing Cooling Problems .............................................24
Fuse Replacement................................................................25
Remove the Refrigerator .......................................................25
Reinstall the Refrigerator ......................................................25
Wiring Pictorial ......................................................................26
Wiring Diagram .....................................................................26
Ice Maker Wiring Pictorial and Diagram (models N640-IM,
N641-IM, N840-IM and N841-IM) ...................................26
Read this manual carefully and understand the contents
before you install the refrigerator.
Be aware of possible safety hazards when you see the safety
alert symbol on the refrigerator and in this manual. A signal
word follows the safety alert symbol and identifies the danger
of the hazard. Carefully read the descriptions of these signal
words to fully know their meanings. They are for your safety.
WARNING: This signal word means a hazard, which
if ignored, can cause dangerous personal injury, death,
or much property damage.
CAUTION: This signal word means a hazard, which if
ignored, can cause small personal injury or much
property damage.
WARNING:
- This refrigerator is equipped for the use of propane gas
only and can not be changed to use any other fuels
(natural gas, butane, etc.).
- Incorrect installation, adjustment, alteration, or mainte-
nance of this refrigerator can cause personal injury,
property damage, or both.
- Obey the instructions in the “Installation Manual” to
install the intake and exhaust vents.
- Do not install the refrigerator directly on carpet. Put the
refrigerator on a metal or wood panel that extends the
full width and depth of the refrigerator.
- Propane gas can ignite and cause a fire or an explo-
sion that can result in property damage, personal
injury, or death. Do not smoke or create sparks while
doing any work on the propane gas supply system. Do
not use an open flame to examine the gas supply
piping or fittings for leaks.
- To avoid possible gas leaks, always use two wrenches
to tighten or loosen the gas supply line connections.
- Make sure the electrical installation obeys all appli-
cable codes. See the “Certification and Code Require-
ments” section of the “Installation Manual”.
- Disconnect both the AC and DC power sources before
doing any maintenance work on the refrigerator.
- Do not bypass or change the refrigerator’s electrical
components or features.
Introduction
This manual supplies information for the experienced repair
technician. The repair technician should have working
knowledge of the operation of an absorption refrigerator
system and should have basic knowledge of LP gas and
electrical systems.
Read the ”Installation Manual”, the “Owner’s Manual”, all
service procedures, cautions, and warnings before you do
any service work on the refrigerator.
If you are unable to resolve the problem using this Service
Manual, technical service support is available at 1-800-543-
1219.
Use only genuine Norcold replacement parts on the refrigera-
tor. Generic parts do not meet Norcold’s specifications for
reliability, performance and safety and will void the Norcold
Limited Warranty.

Service Manual 3
Specifications
Supply Voltage, Fuse, and Wire Size Requirements
- Do not spray liquids near electrical outlets, connec-
tions, or the refrigerator components. Many liquids are
electrically conductive and can cause a shock hazard
and in some cases fire.
- The refrigerator cooling system is under pressure. Do
not try to repair or to recharge a defective cooling
system. The cooling system contains sodium chro-
mate. The breathing of certain chromium compounds
can cause cancer. The cooling system contents can
cause severe skin and eye burns, and can ignite and
burn with an intense flame. Do not bend, drop, weld,
move, drill, puncture, or hit the cooling system.
- Do not remove the round ground prong from the
refrigerator AC power cord. Do not use a two prong
adapter or extension cord on the AC power cord.
- A circuit overload can result in an electrical fire if the
wires and/or fuse sizes used are not correct. Use only
the wire and fuse sizes written in the “Installation
Manual”
- To prevent child entrapment, make sure all shelf
retainers are correctly fastened and remove the doors
before disposing of the refrigerator.
CAUTION:
- The rear of the refrigerator has sharp edges and
corners. To prevent cuts or abrasions when working
on the refrigerator, use caution and wear cut resistant
gloves.
- Make sure all fasteners and connections are tight.
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Service Manual 4
Operating Requirements
Heater Specifications
Other Current Draws
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Service Manual 5
This refrigerator operates on propane gas at a pressure of
10.5 inches Water Column min. to 11.5 inches Water Column
max.
WARNING: Be very careful when working on or near
the propane gas system.
- Do not smoke, or use an open flame near the
propane gas system.
- Do not use an open flame to examine for leaks.
- Do not connect the refrigerator to the propane gas
tank without a pressure regulator between them.
- To avoid possible propane gas leaks, always use
two wrenches to tighten or loosen the gas supply
line connections.
- Leaking propane gas can ignite or explode and
result in dangerous personal injury or death.
Examine the gas supply system for leaks:
WARNING: Do not allow the leak detecting solution to
touch the electrical components. Many liquids are
electrically conductive and can cause a shock hazard,
electrical shorts, and in some cases fire.
Using a solution of liquid detergent and water, make sure the
gas supply line and all gas connections have no leaks. Do
not use any liquid that contains ammonia.
If you use compressed air for the test:
- The pressure of the compressed air at the manual
shutoff valve of the refrigerator must not be more than 1/2
psig (14 inches Water Column).
- If the pressure of the compressed air is more than 1/2
psig (14 inches Water Column), remove the gas supply
line from the manual shutoff valve of the refrigerator
before the test.
- If the pressure of the compressed air is equal to or less
than 1/2 psig (14 inches Water Column), close the
manual shutoff valve of the refrigerator before the test.
Ventilation Requirements
WARNING: The completed installation must:
- Make sure there is sufficient intake of fresh air for
combustion.
- Make sure the living space is completely isolated
from the combustion system of the refrigerator.
- Make sure there is complete and unrestricted
ventilation of the flue exhaust which, in gas mode,
can produce carbon monoxide. The breathing of
carbon monoxide fumes can cause dizziness,
nausea, or in extreme cases, death.
Certified installation needs one lower intake vent and one
upper exhaust vent. Install the vents exactly as instructed in
the “Installation Manual”. Any other installation method voids
both the certification and the factory warranty of the refrigera-
tor.
The bottom of the opening for the lower intake vent, which is
also the service access door, must be even with or immedi-
ately below the floor level. This allows any leaking LP gas to
escape to the outside and not to collect at floor level.
If the vehicle has two side wall vents, the minimum distance
from the floor level to the top of the upper exhaust vent is 55
inches on N6__ models and 62 inches on N8 __ models.
American Gas Association/Canadian Gas Association (AGA/
CGA) certification allows the refrigerator to have zero (0) inch
minimum clearance at the sides, rear, top, and bottom. While
there are no maximum clearances specified for certification,
the following maximum clearances are necessary for correct
refrigeration:
Bottom 0 inch min. 0 inch max.
Each Side 0 inch min 1/2 inch max.
Top 0 inch min. 1/4 inch max.
Rear 0 inch min. 1 inch max.
These clearances plus the lower and upper vents cause the
natural air draft that is necessary for good refrigeration.
Cooler air goes in through the lower intake vent, goes around
the refrigerator coils where it removes the excess heat from
the refrigerator components, and goes out through the upper
exhaust vent. If this air flow is blocked or decreased, the
refrigerator may not cool correctly.
Each NORCOLD model is certified by AGA and CGA for
correct ventilation.
Propane Gas Components

Service Manual 6
This refrigerator operates on these electrical sources.
AC Operation 120 volts AC voltage
(108 volts min. - 132 volts max.)
12 volts DC control voltage
(10.5 volts min. - 15.4 volts max.)
DC Operation 12 volts DC voltage
(3-way models) (10.5 volts min. - 15.4 volts max.)
Operation out of these limits may damage the refrigerator’s
electrical circuit parts and will void the warranty.
Examine the 120 volts AC supply:
WARNING: Connect the AC power cord only to a
grounded three-prong receptacle. Do not remove the
round ground prong from the power cord. Do not use a
two-prong adapter or an extension cord. Operation of
the refrigerator without a correct ground could cause
dangerous electrical shock or death if you are touching
the metal parts of the refrigerator or the vehicle.
- Make sure the AC power cord is in a grounded three-
prong receptacle.
- Make sure the receptacle is within easy reach of the lower
intake vent.
- Make sure the power cord does not touch the burner
cover, the flue pipe, or any hot component that could
damage the insulation of the power cord.
Examine the 12 volt DC supply:
The refrigerator gets power from the 12 volt system of the
vehicle; either from the battery or from an auxiliary (house)
battery. The battery system not only supplies DC power to the
refrigerator, but also to other components of the vehicle.
The DC heating element, which supplies power for cooling
during DC operation, has a high current draw and can cause
rapid battery drain.
Make sure the wire size and fuse size are correct:
- On 2-way models, use a minimum of 18 AWG wire and a
maximum 6 Amp fuse.
- On 3-way models, measure the distance from the vehicle
battery to the refrigerator.
- If the distance is 0 - 20 feet, use a minimum of 10
AWG wire and a 30 Amp fuse.
- If the distance is over 20 feet, use a minimum of 8
AWG wire and a maximum 40 Amp fuse.
- If the wire size is larger than the min. size, use the correct
fuse per RVIA A119.2 standard or local codes.
Electrical Components
Operating the Refrigerator Controls
(models N620, N621, N820, and N821)
- Make sure the positive DC wire from the battery is
connected to the power board terminal that is marked
12VDC.
- Make sure the DC ground wire from the battery is
connected to the power board terminal that is marked
12V GND1.
- Make sure each DC power supply wire is on the correct
polarity terminal.
- Make sure an in-line fuse is installed on the DC positive
wire, as near the battery as possible, between the battery
and the terminal block of the refrigerator.
NOTE: This in-line fuse is necessary for added safety, even
though the refrigerator has a DC fuse in the control
assembly.
Control panel:
The refrigerator control panel (see Art01019) is between the
freezer compartment and the fresh food compartment. To
maintain the operating control functions of the refrigerator, a
12 volt DC power supply is necessary. The refrigerator and
any other DC components in the vehicle, receive DC power
from the 12 volt system of the vehicle; either an auxiliary
battery, a converter, or the vehicle engine battery.
The ON / OFF button [1] starts and shuts down the refrigera-
tor:
- If the refrigerator is shut down, press the ON / OFF button
to start the refrigerator in auto mode.
- If the refrigerator is operating, press and hold the ON /
OFF button for two seconds to shut down the refrigerator.
The TEMP SET button [2] controls the temperature adjust-
ment of the freezer and the fresh food compartment. The
temperature adjustment that you select does not change if
the mode of operation of the refrigerator changes.
- Push the TEMP SET button and the temperature setting
“1-9” appears in the center display [3].
- Push and hold the TEMP SET button and the temperature
setting changes.
- The number “9” is the coldest temperature setting.

Service Manual 7
The MODE button [8] controls the operation mode of the
refrigerator.
- Push and hold the MODE button and a light bar flashes in
the center display beside each of the four operating
modes of the refrigerator, one at a time.
- There is one automatic mode of operation and three
manual modes of operation.
- When the light bar flashes beside the mode of
operation that you wish, release the MODE button.
Automatic mode operation:
When you select AUTO mode, the refrigerator controls
automatically select the most efficient energy source that is
available for operation. If a more efficient energy source
becomes available, the refrigerator controls change from the
current energy source to the more efficient energy source.
The controls select the energy source in this sequence:
- When 120 volts AC is available to the refrigerator:
- The light bars beside AUTO [3] and AC [4] show in
the center display.
- After ten seconds, the light bar beside AC goes off
and only the light bar beside AUTO remains.
- This means that the refrigerator is operating on AC
electric.
- If 120 volts AC is not available to the refrigerator:
- The light bars beside AUTO and LP GAS [6] show in
the center display.
- After ten seconds, the light bar beside LP GAS goes
off and only the light bar beside AUTO remains.
- This means that the refrigerator is operating on
propane gas.
If an energy source is available to the refrigerator, but is not
operating correctly:
- A fault code appears in the center display.
- The refrigerator controls try to change to a less efficient
energy source.
- If a less efficient energy source is not available:
- The refrigerator stops operation.
- Refer to the “Fault Codes” section of this manual.
Manual mode operation:
When you select one of the manual modes of operation, The
light bar beside the AUTO goes out in the center display and
only the light bar beside either AC, LP GAS, or DC remains.
- AC means that the refrigerator is operating on AC electric.
- LP GAS means that the refrigerator is operating on
propane gas.
If the energy source is interrupted:
- The refrigerator stops operation.
- Refer to the “Fault Codes” section of this manual.
Ignition of LP gas in either auto or manual mode:
NOTE: On initial start up of the refrigerator, ignition of the
propane gas may not occur within 30 seconds.
If ignition of the propane gas does not occur within 30
seconds:
- The gas safety valve of the refrigerator closes.
- The refrigerator stops operation.
- Refer to the “Fault Codes“ section of this manual.
- The fault code remains until you push the ON / OFF
button two times (to stop and start the refrigerator).
- If ignition does not occur after two or three times:
- Check the gas supply line.
- Refer to the “Gas Ignition Fault” chart that is in the
“Troubleshooting” section this manual.

Service Manual 8
Operating the Refrigerator Controls
(models N640, N641, N640-IM, N641-IM,
N840, N841, N840-IM, and N841-IM)
Control panel:
The refrigerator control panel (See Art01018) is between the
freezer compartment and the fresh food compartment. To
maintain the operating control functions of the refrigerator, a
12 volt DC power supply is necessary. The refrigerator and
any other DC components in the vehicle, receive DC power
from the 12 volt system of the vehicle; either an auxiliary
battery, a converter, or the vehicle engine battery.
The ON / OFF button [1] starts and shuts down the refrigera-
tor:
- If the refrigerator is shut down, push the ON / OFF button
to start the refrigerator in auto mode.
- If the refrigerator is operating, push and hold the ON /
OFF button for two seconds to shut down the refrigerator.
The TEMP SET button [3] controls the temperature adjust-
ment of the freezer and the fresh food compartment. The
temperature adjustment that you select does not change if
the operation mode of the refrigerator changes.
- Push the TEMP SET button and the temperature setting
“1-9” appears in the center display [4].
- Push and hold the TEMP SET button and the temperature
setting changes.
- The number “9” is the coldest temperature setting.
The MODE button [2] controls the operation mode of the
refrigerator:
- Push and hold the MODE button and each of the four
operating modes of the refrigerator flash one at a time in
the center display.
- There is one automatic mode of operation and there
are three manual modes of operation.
- When the mode of operation that you wish shows in
the center display, release the MODE button.
Automatic mode operation:
When you select AUTO mode, the refrigerator controls
automatically select the most efficient energy source that is
available for operation. If a more efficient energy source
becomes available, the refrigerator controls change from the
current energy source to the more efficient energy source.
The controls select the energy source in this sequence:
- When 120 volts AC is available to the refrigerator:
- “AU” “AC” flashes in the center display.
- This means that the refrigerator is operating on AC
electric.
- After ten seconds, the “AU” “AC” goes off and only a
power indicator remains.
- If 120 volts AC is not available to the refrigerator:
- “AU” “LP” flashes in the center display.
- This means that the refrigerator is operating on
propane gas.
- On 3-Way models only, if neither 120 volts AC nor
propane gas is available to the refrigerator:
- “AU” “dc” flashes in the center display.
- This means that the refrigerator is operating on DC
electric.
NOTE: DC electric operation is less efficient than AC
electric and propane gas. Use DC electric
operation only to maintain the refrigerator
temperature while in transit and if the other
energy sources are not available. Do not use
DC electric to initially decrease the tempera-
ture of the refrigerator.
If an energy source is available to the refrigerator, but is not
operating correctly:
- A fault code shows in the center display.
- The refrigerator controls try to change to a less efficient
energy source.
- If a less efficient energy source is not available:
- An audible alarm starts.
- The refrigerator stops operation.
- Refer to the “Fault Codes” section of this manual.

Service Manual 9
This refrigerator has a backup operating system. The backup
operating system allows the refrigerator to continue to cool if
the temperature sensor of the refrigerator should fail.
If this failure occurs:
- The refrigerator automatically changes to the backup
operating system.
- When you push the TEMP SET button, the tempera-
ture setting flashes in the center display for ten
seconds.
- After the temperature setting flashes, the mode of
operation appears in the center display.
- The backup operating system can over freeze or thaw the
contents of the freezer and the fresh food compartment.
- Make sure the temperatures of the freezer and the
fresh food compartment are satisfactory.
NOTE: If you open the door(s) too often, the tempera-
tures inside the freezer and fresh food
compartment do not become stable. Allow the
refrigerator to operate for about one hour after
each adjustment change before you examine
the contents. The number “9” is the coldest
temperature setting.
- If the temperature is too warm, push and hold
the TEMP SET button to raise the temperature
setting by one number.
- If the temperature is too cold, push and hold the
TEMP SET button to lower the temperature
setting by one number.
- The owner should have the refrigerator serviced by a
dealer or an Norcold authorized Service Center as soon
as possible.
Backup Operating System
Manual mode operation:
When you select one of the three manual modes, “AU” goes
out in the center display and either “AC”, “LP”, or “dc” appears.
- “AC” means that the refrigerator is operating on AC
electric.
- “LP” means that the refrigerator is operating on propane
gas.
- “dc” means that the refrigerator is operating on DC
electric.
If the energy source is interrupted:
- An audible alarm starts.
- The refrigerator stops operation.
- Refer to the “Fault Codes” section of this manual.
Ignition of propane gas in either auto or manual
mode:
NOTE: On initial start up of the refrigerator, ignition of the
propane gas may not occur within 30 seconds.
If ignition of the propane gas does not occur within 30
seconds:
- The gas safety valve of the refrigerator closes.
- In the Auto mode:
- The refrigerator control changes to a less efficient
energy source (3-way models only).
- The fault code “no” “FL” shows in the center display
(2-way models only).
- In the Manual mode and operating on propane gas:
- An audible alarm starts.
- The fault code “no” “FL” shows in the center display.
- The audible alarm and the fault code remain until you
push the MODE button.
- Push the ON/OFF button two times to stop and start
the refrigerator.
- If ignition does not occur after two or three times:
- Check the gas supply line.
- Refer to the “Propane Gas Ignition Fault” chart that is
in the “Troubleshooting” section this manual.

Service Manual 10
Fault Codes (models N620, N621, N820, and N821)
sedoCtluaFgninaeMedoCtluaF noitcAevitcerroC ehtnisitahttrahcehtotrefeR .launamsihtfonoitces"gnitoohSelbuorT"
.yalpsidoN ehtotelbaliavanusiegatlovCD ehtrolenaplortnocrotaregirfer .FFOsirotaregirfer .NOrotaregirfernruT ."lenaPlortnoCnOyalpsiDoN"otrefeR
"d" sawroodtnemtrapmocdoofehT .setunimowtnahteromrofnepo ."rajArooDtnemtrapmoCdooFhserF"otrefeR
"F" roetingitondidrenrubehT .etingier ."eruliaFnoitingIsaGPL"otrefeR
"A" ehtotelbaliavanusiegatlovCA .lenaplortnocrotaregirfer ."elbaliavAtoNrewoPCA"otrefeR
"E" rotaregirferehtotegatlovCD .hgihootsilenaplortnoc ."hgiHooTsiegatloVCD"otrefeR
"C" rotaregirferehtotegatlovCD .wolootsilenaplortnoc ."woLooTsiegatloVCD"otrefeR
"H".desolckcutssiyalerCA "tluaFtuptuOretaeHCA"otrefeR
"P".nepodeliafsahretaehCA ."nepOdeliaFretaeHCA"otrefeR
"S".deliafsahtiucricesnesemalF ."eruliaFtiucriCesneSemalF"otrefeR
ynahsupuoynehW erutarepmeteht,nottub netrofsehsalfgnittes ehtnehtdnasdnoces .sraeppaedom
nognitareposirotaregirferehT ."metsySgnitarepOpUkcaB"eht ."metsySgnitarepOpUkcaB"otrefeR
35010trA

Service Manual 11
Fault Codes (models N640, N641, N640-IM, N641-IM, N840, N841, N840-IM, and N841-IM)
sedoCtluaFgninaeMedoCtluaF noitcAevitcerroC ehtnisitahttrahcehtotrefeR .launamsihtfonoitces"gnitoohSelbuorT"
.yalpsidoN ehtotelbaliavanusiegatlovCD ehtrolenaplortnocrotaregirfer .FFOsirotaregirfer .NOrotaregirfernruT ."lenaPlortnoCnOyalpsiDoN"otrefeR
"rd" .oslamralaelbiduA sawroodtnemtrapmocdoofehT .setunimowtnahteromrofnepo .mralaehtecnelisotnottubEDOMehthsuP ."rajArooDtnemtrapmoCdooFhserF"otrefeR
"LF""on" .oslamralaelbiduA roetingitondidrenrubehT .etingier .mralaehtecnelisotnottubEDOMehthsuP ."eruliaFnoitingIsaGPL"otrefeR
"CA""on" .oslamralaelbiduA ehtotelbaliavanusiegatlovCA .lenaplortnocrotaregirfer .mralaehtecnelisotnottubEDOMehthsuP ."elbaliavAtoNrewoPCA"otrefeR
"OL""CA" rotaregirferehtotegatlovCA .wolootsilenaplortnoc ."woLooTsiegatloVCA"otrefeR
"IH""CA" rotaregirferehtotegatlovCA .hgihootsilenaplortnoc ."hgiHooTsIegatloVCA"otrefeR
"OL""cd" rotaregiferehtotegatlovCD .wolootsilenaplortnoc ."woLooTsIegatloVCD"otrefeR
"IH""cd" rotaregirferehtotegatlovCD .hgihootsilenaplortnoc ."hgiHooTsIegatloVCD"otrefeR
"Er""CA" .oslamralaelbiduA .desolckcutssiyalerCA .mralaehtecnelisotnottubEDOMehthsuP "tluaFtuptuOretaeHCA"otrefeR
Er""cd" .oslamralaelbiduA .desolckcutssiyalerCD .mralaehtecnelisotnottubEDOMehthsuP "tluaFtuptuOretaeHCD"otrefeR
"EH""CA" .oslamralaelbiduA .nepodeliafsahretaehCA .mralaehtecnelisotnottubEDOMehthsuP ."nepOdeliaFretaeHCA"otrefeR
"EH""cd" .oslamralaelbiduA .nepodeliafsahretaehCD .mralaehtecnelisotnottubEDOMehthsuP ."nepOdeliaFretaeHCD"otrefeR
"rS" .oslamralaelbiduA .deliafsahtiucricesnesemalF .mralaehtecnelisotnottubEDOMehthsuP ."eruliaFtiucriCesneSemalF"otrefeR
ynahsupuoynehW erutarepmeteht,nottub netrofsehsalfgnittes ehtnehtdnasdnoces .sraeppaedom
nognitareposirotaregirferehT ."metsySgnitarepOpUkcaB"eht ."metsySgnitarepOpUkcaB"otrefeR
45010trA

Service Manual 12
Troubleshooting

Service Manual 13

Service Manual 14

Service Manual 15

Service Manual 16
The control senses AC
heater current when the AC
heater should be OFF.
AC Heater Output Failure.
Art01063
Replace
power board.
The control senses DC
heater current when the DC
heater should be OFF.
DC Heater Output Failure.
Art01064
Replace
power board.

Service Manual 17

Service Manual 18

Service Manual 19
Control Diagnostic Function
(models N620, N621, N820, and N821)
The Control Diagnostic Function allows the repair technician
to put the refrigerator control into a diagnostic display mode.
This mode provides the repair technician with specific
diagnostic information which can be helpful when trouble-
shooting refrigerator control problems.
The diagnostic display mode consists of eight different
display screens. While each of these screens show different
information, they all use the individual segments of the 7-
segment display. The individual segments are:
To put the refrigerator control into the diagnostic display
mode, push the TEMP SET and MODE buttons at the same
time and hold them for five seconds. “1”, which means
diagnostic screen #1, will appear for two seconds. The
contents of diagnostic screen #1 will then appear until you
push the MODE button again.
Each time you push the MODE button, the next diagnostic
screen # appears for two seconds and then the contents of
the diagnostic screen appears. After screen # 9, the diagnos-
tic screens start again with screen #1.
Diagnostic Screen #1:
All display segments appear.
Diagnostic Screen #2:
No display segments appear.
Diagnostic Screen #3: Thermistor Temperature
The thermistor temperature appears in °F.
- The first digit of the temperature appears for one second
and the second digit of the temperature appears for one
second.
- Then no segments appear for a two second pause.
- This cycle repeats until you push the MODE button.
segment 1
segment 2 segment 3
segment 7
segment 5 segment 6
segment 4
Art01075
Diagnostic Screen #4: Fault History
Individual segments appear for these recorded faults:
Segment 1 ............ Ignition fault.
Segment 2 ............ Door ajar.
Segment 3 ............ DC voltage low.
Segment 4 ............ DC voltage high.
Segment 5 ............ AC mode selected but not available.
Segment 6 ............ AC relay stuck closed.
Segment 7 ............ AC heater failed open.
Diagnostic Screen #5: Fault History - Continued
Individual segments appear for these recorded faults:
Segment 1 ............ Thermistor failure.
Segment 2 ............ Flame sense failure.
Diagnostic Screen #6: Erase Fault History
“E” appears for one second. Then “r” appears for one
second. After a two second pause, the cycle continues to
repeat as long as this display screen is active.
To erase the fault history:
- Push “TEMP SET” for five seconds.
- “C” appears for one second.
- Then “L” appears for one second.
- After a two second pause, the cycle continues to
repeat as long as this state is active.
- Push “TEMP SET” again for five seconds.
- “E” appears for one second.
- Then “r” appears for one second.
- After a two second pause, the cycle continues to
repeat as long as this display screen is active.
Diagnostic Screen #7: Inputs
Individual segments appear for these inputs to the refrigera-
tor controls:
Segment 1 ............ Door of the fresh food compartment is
closed and interior light is off.
Segment 2 ............ Burner flame is sensed.
Segment 3 ............ Thermistor is sensed.

Service Manual 20
Diagnostic Screen #8: Outputs
Individual segments appear for these outputs from the
refrigerator controls:
Segment 1 ............ The power board is supplying power to
the AC heater.
Segment 2 ............ The power board is supplying power to
the DC heater.
Segment 3 ............ The power board is supplying power to
the divider heater.
Segment 4 ............ The power board is supplying power to
the gas valve.
Segment 5 ............ The power board is supplying power to
the interior light.
Segment 6 ............ The power board is supplying power to
the spark electrode.
Diagnostic Screen #9: DC Voltage Status
The screen number appears in the left display. The individual
segments of the right display appear for the status of the DC
voltage:
Segment 1 ............ DC voltage high.
Segment 4 ............ DC voltage normal.
Segment 7 ............ DC voltage low.
Control Diagnostic Function
(models N640, N641, N640-IM, N641-IM,
N840, N841, N840-IM, and N841-IM)
The Control Diagnostic Function allows the repair technician
to put the refrigerator control into a diagnostic display mode.
This mode provides the repair technician with specific
diagnostic information which can be helpful when trouble-
shooting refrigerator control problems.
The diagnostic display mode consists of ten different display
screens. While each of these screens show different informa-
tion, they all use the individual segments of the 7-segment
displays. The individual segments are:
To put the refrigerator control into the diagnostic display
mode, push the TEMP SET and MODE buttons at the same
time and hold them for five seconds. “1”, which means
diagnostic screen #1, will appear for two seconds on the left
display. The contents of diagnostic screen #1 will then
appear until you push the MODE button again.
segment 1
segment 2 segment 3
segment 7
segment 5 segment 6
segment 4
Art01075
Each time you push the MODE button, the next diagnostic
screen # appears for two seconds and then the contents of
the diagnostic screen appears. After screen # 0 (ten), the
diagnostic screens start again with screen #1.
Diagnostic Screen #1:
All display segments appear on both displays.
Diagnostic Screen #2:
No display segments appear on either display.
Diagnostic Screen #3: Thermistor Temperature
The thermistor temperature appears in °F using both
displays.
Diagnostic Screen #4: Fault History
The screen number appears in the left display. The individual
segments of the right display appear for these recorded
faults:
Segment 1 ............ Ignition fault.
Segment 2 ............ Door ajar.
Segment 3 ............ DC voltage low.
Segment 4 ............ DC voltage high.
Segment 5 ............ AC mode selected but not available.
Segment 6 ............ AC relay stuck closed.
Segment 7 ............ AC heater failed open.
Diagnostic Screen #5: Fault History - Continued
The screen number appears in the left display. The individual
segments of the right display appear for these recorded
faults:
Segment 1 ............ Thermistor failure.
Segment 2 ............ Flame sense failure.
Segment 3 ............ DC relay stuck closed.
Segment 4 ............ DC heater failed open.
Segment 5 ............ AC voltage low.
Segment 6 ............ AC heater failed open.
Diagnostic Screen #6: Erase Fault History
“E” “r” appears for one second and then pauses for two
seconds. The cycle continues to repeat as long as this
display screen is active.
To erase the fault history:
- Push “TEMP SET” for five seconds.
- “C” “L” appears for one second and then pauses for
two seconds.
- The cycle continues to repeat as long as this state is
active.