Viking VUWC140 Service manual

F90571 F90571

TABLE OF CONTENTS
General Information-------------------------------------------------------------------------------- 4
Most often Misdiagnosed Problem--------------------------------------------------------------- 4
Troubleshooting Guide
1. Interior too Cool or Contents Freezing-------------------------------------- 6
2. Interior too Warm (Compressor Operates)--------------------------------- 8
3. Excessive Frost Build-up on Evaporator. (Interior Temperatures
Normal and Frost Pattern Uniform.)----------------------------------------- 10
4. Compressor, Fan and Interior Light do not Function--------------------- 11
5. Interior Light Functions but Compressor will not Run------------------- 12
6. Compressor Runs, Fan does not Run------------------------------------------ 12
7. Fan Runs, but Compressor does not Run------------------------------------- 12
8. Interior Light will not turn OFF when Door is Closed--------------------- 12
Thermostat Specifications---------------------------------------------------------------------------- 13
Wiring Diagram---------------------------------------------------------------------------------------- 14
Appendix: Solid State Control---------------------------------------------------------------------- 15
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VIKING RANGE ALL-REFRIGERATION MODELS
VUWC140/150—VUAR140/150—VRBD—VUBD
The all-refrigerator product line encompasses traditional all-refrigerators, beverage storage all-
refrigerators with temperature barriers to create different temperature zones, refrigerator
beverage dispensers, and wine storage refrigerators.
All these models employ an evaporator plate for cooling the cabinet interior and an evaporator
plate sensing thermostat to control the compressor operation and therefore, the interior
temperature.
A cycle defrost system is also used on all these models. The plate sensing thermostat is designed
such that at the end of each compressor run cycle, the evaporator plate must “warm-up” above a
freezing temperature before the compressor will restart. During this “warm-up” period, any
accumulated frost on the evaporator melts and drips off the evaporator plate into drip channels
and a drip tray. From the drip tray, a drain tube carries the defrost water to a pan in the
mechanical compartment. There, condenser fan air movement and compressor heat evaporate
the water.
Most Often Misdiagnosed Problem
Sealed refrigeration system leaks are the most often misdiagnosed problem on the Viking all-
refrigerator models. The interaction between the evaporator sensing thermostat, the mounting
location of the thermostat thermobulb, and a low refrigerant condition within the evaporator,
yields a condition in which the cabinet interior air temperature drops below freezing and stored
commodities become frozen.
End users respond to the colder interior temperatures by adjusting the thermostat knob to a
warmer setting, until they reach the warmest available. When their stored commodities continue
to freeze at the warmest setting, they call for service. The end user states the problem as “the
thermostat is set at its warmest setting yet everything inside freezes.”
This leads most service technicians to suspect a bad thermostat. When the technician examines
the unit and finds that the compressor runs continuously, the tentative diagnosis is confirmed.
The technician’s diagnosis is that the thermostat is not functioning properly and he replaces it.
When this does not correct the problem, often the thermostat is replaced a second time because
the technician believes the first replacement thermostat might have also been defective. By this
time, the end user is upset because the technician cannot repair his unit and the technician is
contacting the Viking Customer Services Department to inform us that he has received two
“defective” thermostat service assemblies!
What a mess! Let’s back-up to the beginning to determine where this service call went wrong.
When the end user stated the problem as “the thermostat is set at its warmest setting yet
everything inside freezes”, the technician automatically thought, “too much run time”, probably
bad thermostat. But the problem was actually a low refrigerant charge or leak. Typically, when
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Customers complain about a refrigerator operating too cold, we don’t usually think about a low
refrigerant charge or leak. A low charge or leak typically causes the opposite problem – the
interior becomes too warm as the system runs out of cooling capacity.
The rest of the problem is the “unique” way, some call it the “backwards” way, that the Viking
all refrigerator models react to a low refrigerant volume condition.
When there is a low refrigerant condition in the unit, the gas volume is insufficient to fill all the
tracks in the plate evaporator. As a result, areas not filled with gas do not achieve the very cold
plate sensing thermostats cut-out temperatures. Therefore, whenever the remaining refrigerant
gas volume is not sufficient to fill the area of the evaporator where the thermostat’s sensing
thermobulb is mounted, the compressor runs continuously. Usually the cooling capacity of the
remaining portion of the evaporator which still contains refrigerant, is sufficient to achieve air
temperatures below freezing in the unit when the compressor runs continuously.
Therefore, when dealing with plate sensing thermostats, as opposed to air temperature sensing
thermostats, we must adjust our thinking about how the sealed refrigeration system can react to a
low or leak condition. The conditions described above are representative of a slow leak where
the system still retains a partial charge.
The recommended diagnostic approach for complaints of “operation too cold on lowest setting”
is to insure the compressor is operating and then open the unit door. Allow the door to remain
open for about 5 minutes and observe the frost pattern that forms on the evaporator.
On a properly charged unit, the frost pattern should be continuous and uniform over the entire
surface of the evaporator. The frost pattern should extend from the left-hand wing of the
evaporator across the back segment and around to the right-hand wing. If this frost pattern is
present, the thermostat or its thermo-bulb mount are possible the source of the too cold
condition.
On a unit with a low charge or leak condition, the frost pattern, if present, will typically cover the
left wing and perhaps a part of the back. It will not be present on the entire back or right wing of
the evaporator plate as viewed.
The thermo-bulb mounting location on the VRBD—VUBD—VUAR is at the top of the
evaporator plate on the portion across the rear of the cabinet. On the model VUWC, the thermo-
bulb is mounted to the right wing of the evaporator plate as viewed.
When an incomplete frost pattern is present which does not cover the area where the thermo-bulb
is mounted, the problem is a leak or low refrigerant charge. Changing the thermostat will not
correct the “too cold” condition. Locating the leak, sealing it and evacuation and recharging the
system is the only permanent solution. Leak check all braze joints on the refrigerant tubes and
check all sealed system components for the source of the leak. Include the tubes themselves, the
process stub close-out welds and the copper-to-aluminum braze way joints at the evaporator inlet
and outlet. The braze way welds are difficult to leak check in the cabinet. If the rest of the
system has been thoroughly checked and no leaks have been found, the braze ways are the likely
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source of a leak. The braze ways cannot be brazed/repaired. The evaporator assembly must be
replaced to repair a leak in this area.
Occasionally, corrosion develops under the thermo-bulb mounting clamp causing a leak, so leak
check this area thoroughly. Also, if this is the leak source, replace the evaporator assembly.
Hopefully, this information will help you properly diagnose sealed refrigeration system leak
conditions which you encounter on Viking all-refrigerator models in the field. When these
problems are properly diagnosed and promptly repaired, the customer, the service technician and
Viking all benefit.
TROUBLESHOODTING FOR VIKING ALL-REFRIGERATOR
AND WINE STORAGE ALL-REFRIGERATOR MODELS
PROBLEM CHECK POSSIBLE CAUSE REMEDY
1. Interior too a. Thermostat 1. Thermostat set to 1. Adjust thermostat to warmer
cold or setting too cold of a setting (lower number on
contents . setting for ambient knob)
freezing. conditions.
b. The evaporator 1. Refrigerant leak 1. locate and correct cause of
for the presence or low refrigerant refrigerant leak. Replace
of a uniform charge in the drier, evaporator, and
frost pattern sealed system. Recharge sealed
Is the frost Refrigerant volume refrigerant system with
confined to left is evaporator is not the proper amount of
wing and left sufficient to cool charge as listed on the
side of the the region of the unit’s data plate.
back? Note plate where the
compressor evaporator plate
should be sensing thermo-
operating for at stat’s thermo-bulb
least 5 minutes mounts. Therefore
with door open the control thermo-
to perform this stat never reaches
check. See its cut-out
previous page temperature and
for explanation the compressor
unique problem. Operates 100% of
the time. The
remaining evapor-
ator volume is
sufficient to cool
the air temperature
below freezing.
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PROBLEM CHECK POSSIBLE CAUSE REMEDY
c. Thermostat 1. Mounting location 1. Relocate thermo-bulb
(compressor incorrect. Model to proper location
control) VUCW should be
thermo-bulb on the right wing
mounting of the evaporator
or routing. plate. All other
models mount at
rear top center of
the evaporator.
2. Thermostat sensing 2. Reroute sensing tube clear
tube (capillary tube) of compressor dome area.
resting on or above
compressor dome
in mechanical
compartment causing
false sensing.
3. Thermostat 3. Securely tighten
thermo-bulb thermo-bulb mounting
mounting bracket bracket.
not secure, causing
false sensing.
4. Insufficient 4. Adjust thermo-bulb
thermo-bulb contact contact area to achieve
area. on evaporator sufficient contact.
U-shaped loop with A U-shaped loop with
3-inch long legs 3-inch long legs is required.
required bracket The mounting bracket
Bracket should be should be located at the
located at midpoint mid point of each 3-inch
of each 3-inch leg. leg. Both legs secured
Both legs secured under bracket.
under bracket
d. Compressor 1. Cut-out temperature 1. Replace the thermostat
control too low due to internal
thermostat failure in the
cut-out thermostat
temperature.
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PROBLEM CHECK POSSIBLE CAUSE REMEDY
e. Placement of 1. If white rubber “shelf 1. Properly place the glass
glass shelves bumper” do not space shelves in the unit. White
in cabinet the glass shelf out away rubber “shelf bumper”
from the molded inner- must be placed so as to
liner shelf supports on create an air space gap
the back of the cabinet between the rear edge of
interior. The cold air the glass shelf and the
from the evaporator can molded shelf supports on
be “trapped” above the the cabinet interior.
the shelf resulting in
the area above the
shelf becoming too
cold and below too
warm. (This applies to
models with glass
shelves only.)
2. Interior a. Thermostat 1. Thermostat set to too 1. Adjust thermostat, to a
too warm low (warm) of a setting. colder setting (higher
number on knob).
2. Thermostat failed, 2. Replace thermostat. Leak
cutting compressor check the sealed
off too soon. Refrigeration system.
Locate and correct the
source of the leak.
Replace the drier and
recharge to proper
amount.
2a. Replace the thermostat
with the solid state AC
control..(See appendix
page15).
b. the evaporator 1. Refrigerant leak. 1. Leak check the sealed
for the presence refrigeration system.
of a frost locate and correct the
pattern not source of the leak. Replace
present with the drier and recharge to
compressor proper amount.
operating.
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PROBLEM CHECK POSSIBLE CAUSE REMEDY
c. High and low 1. Compressor valve failure, 1. Replace compressor and
side pressure preventing compressor drier, evacuate and
in the sealed from developing required recharge with refrigerant
system. refrigerant pressures for to the proper amount.
system operation.
2. Restriction in the sealed 2. Locate the restriction and
refrigerant system correct the cause. Evacuate,
causing high compressor replace drier and recharge
discharge pressures and the sealed refrigeration
low pressure or vacuum system to the proper level.
Conditions on the suction
side. Pressure does not
equalize quickly when
the compressor is turned
off.
d. Interior light-- 1. Striker plate on bottom 1. Replace or install striker
does it remain of door not present or plate on door so light
on with door not positioned properly switch is depressed when
closed, adding to depress light switch in door is closed.
heat to the grille area when door is
closed.
2. Failed light activation 2. Replace light activation
switch not turning off switch.
light when switch is
depressed.
3. Wiring connection to or 3. Correct improper wiring
from light activation connection.
switch improperly wired
bypassing switch.
4. Door light activation 4. Place over-ride switch in
switch over-ride switch the “door” position. Verify
in the “on” position light goes out when door
permitting light to remain is closed by depressing
“on” with door closed. Light activation switch
(Present on some but and confirming light goes
not all models.) out.
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PROBLEM CHECK POSSIBLE CAUSE REMEDY
e. Condenser fan 1. Condenser fan blade 1. Free condenser fan blade
operation. jammed against shroud so it rotates freely.
or otherwise bound.
2. Wiring connection to 2. Correct loose or incorrect
and from fan motor, wiring connections.
terminal block and
thermostat loose or
incorrect.
3. Condenser fan motor 3. Replace condenser fan
failed. Assembly.
f. Condenser air 1. Condenser air flow 1. Clean condenser to restore
flow blocked blocked by dirt, lint, air flow.
or restricted. trash , etc.
2. Air flow in or out of toe 2. Clear restriction to air flow
space grille restricted. Through toe space grille.
No obstruction to air flow
permitted in an area 3
feet out from the grille.
3.Excessive a. Cabinet for 1, Exterior door of unit not 1. Install door shim kit to
frost built- proper sealing hanging straight, correct hang of door.
Up on (absence of preventing proper gasket
Evaporator air leaks). sealing.
(interior
temperatures 2. Door hinges bent. 2. Install new hinge kit to
are normal correct hang of door.
and frost Door shims may also be
pattern is required. See hinge and
uniform). Shim installation
instructions.
3. Air leaks at locations 3. Seal around these entry
where refrigerant line, points with refrigeration
electrical wiring or putty (permagum) to
thermostat capillary tubes eliminate air leaks.
enter cabinet interior.
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PROBLEM CHECK POSSIBLE CAUSE REMEDY
4. Air leaks around door 4. Reform gasket using heat
gasket due to physical to achieve a complete
contour of gasket. seal.
5 Door gasket torn or has 5. Replace gasket if stiff
lost magnetism. or has weak magnetism.
6. Damage to cabinet front 6 Straighten area to permit
flange (gasket sealing proper seal. If unable
area). to achieve proper seal,
unit is non-repairable.
b. Extended or 1. Extended or too frequent 1. Reduce frequency and
too frequent door openings allow duration of door
door openings. warm, moist air to reach openings.
cold evaporator plate
causing heavier frost
built-up.
4. Compressor a. Power supply. 1. Unit not plugged into 1. Plug unit into power
and interior power outlet. outlet.
lights don’t
function. 2. Fuses or circuit breaker 2. Replace fuse. Reset
tripped. circuit breaker. Correct
power supply problem.
b. Power cord 1. Loose or incorrect 1. correct loose or incorrect
and wiring wiring connections at wiring connections.
connections power cord, thermostat
within unit input or terminal block.
from power
cord to
thermostat
and terminal
block.
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PROBLEM CHECK POSSIBLE CAUSE REMEDY
5. Interior a. Compressor 1. Compressor control 1. Replace compressor
light functions control thermostat. control thermostat.
but compressor thermostat.
will not run. 2. Wiring connections 2. Correct loose or incorrect
from compressor control wiring connections.
Thermostat to terminal
Block loose or incorrect.
6. Compressor a. Fan motor 1. Fan blade jammed by 1. Free fan blade so fan
runs: fan does blade shroud, refrigerant line, operates freely.
not run. assembly. mount bracket, foreign
objects, etc.
2. Fan motor failed. 2. Replace fan motor.
3. Connection loose or 3. Correct loose or incorrect
incorrect on wiring from wiring connections.
fan motor to terminal
block.
7. Fan runs, but a PTC starter. 1. Failed PTC starter. 1. Replace PTC starter.
b. Wiring PTC 1. loose or incorrect 1. Correct loose or incorrect
start to wiring connections at wiring.
terminal PTC starter to terminal
block. block.
c. Compressor 1. Failed motor in 1. Replace compressor
compressor.
2. Compressor cycled off 2. Unplug unit. Allow
on thermal overload compressor to cool 30-45
protector. minutes. Plug unit in.
If compressor starts, locate
cause of thermal overload.
may be power interruption,
high ambient temperature,
or fan/condenser blocked.
8. Interior light a. Striker plate 1. Striker plate not present 1. Replace or install striker
will not turn on bottom or not positioned plate so light switch is
of door. properly to depress light depressed when door is
switch when door is closed.
closed.
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PROBLEM CHECK POSSIBLE CAUSE REMEDY
b. Light activation 1. Failed light activation 1. Replace light activation
switch. switch. switch.
c. Wiring 1. Improperly wired bypass 1. Correct improper wiring
connection to switch or over-ride connections
and from light switch.
activation switch
and over-ride
switch.
d. Position of door 1. If over-ride switch is in 1. Place over-ride switch in
light activation the “on” position instead the “door” position. Verify
over-ride switch of the “door” position, light goes out when door
is in the “on” the light will remain on is closed by depressing
position. with the door closed. light activation switch
This is intended for and confirming light goes
glass door viewing out.
with door closed.
e. Over-ride switch 1. Failed over-ride switch. 1. Replace over-ride switch.
operation.
THERMOSTAT SPECIFICATIONS
VUAR—VRBD—VUBD
Thermostat (°F) (°F)
Knob Setting Cut-In Cut-Out
Warmest
Setting No. 1 38°±2.7°7.5°±2.7°
Mid
Setting No. 3 ½ 38°±1.5°1°±2°
Coldest
Setting No. 7 38°±2.7°.6°±2.7°
• Light bulb is intermediate 15 watt bulb. DO NOT use a higher wattage bulb.
• Optional item.
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WIRING DIAGRAM
VUAR—VUWC
WIRING DIAGRAM
VUBD—VRBD
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APPENDEX:
INSTRUCTIONS FOR FIELD INSTALLATION SOLID STATE AC CONTROLS ON VUAR140 / VRBD /
VUBD / VUAR150 / VUWC150 ONLY
TOOLS NEEDED: 5/16” NUT DRIVER AND PHILLIPS SCREW DRIVER
.
1. Before working on the unit unplug it first.
2. Using the Phillips screwdriver, remove
the screws from the grille on the front
of the unit.
3. Carefully pull the wires off of the old
thermostat.
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15
4. Unscrew the thermostat from the
bracket.
5. Loosen the screw holding the
thermobulb clamp on.
6. Gently remove the thermobulb away
from clamp.
7. Go to rear of unit and gently pull the
capillary tube from the thermostat out
of the unit.
8. Set dip switches for the correct unit.(Ill
# 1)
9. Mount control on base plate in location
shown in the supplied drawing.
10. Plug in molded connector from the
power cord to control (match up
according to the color of the wires).
11. Install neutral wire to control.
12. Install Potentiometer according to
supplied drawing.
13. Route wire back and plug into control.
14. Feed thermistor from the back and
install on evaporator plate
15. Route remaining thermistor wire along
insulated tube and cable tie securely.
16. Plug thermistor into control.
17. Put unit back together.
TERMINAL BLOCK