SUB-ZERO Wine Storage (400-2) Series Troubleshooting Guide

This document provides troubleshooting procedures for SUB-ZERO Wine Storage appliances, specifically focusing on temperature issues, error codes, and general operational problems.

Troubleshooting Guides Overview

This section of the manual outlines the available troubleshooting resources:

Temperature Problem Diagnostic Worksheets (Note: does not apply to 427R-2 refrigerator section)
Error Code Tables and Error Code Troubleshooting Guides
General Troubleshooting Guide (Wine storage and 427R-2 Refrigerator Section)
Sealed System Diagnostic Tables
Membrane Switch/Ribbon Cable Test Procedures

Temperature Problem Diagnostic Worksheet

This worksheet helps identify the cause of temperature problems in a wine storage unit. Familiarity with Diagnostic Mode and Temperature Log Recall Mode is required.

Note: This worksheet does not apply to temperature problems in the refrigerator section of a 427R-2.

Steps to follow:

Write down temperatures shown on the display. If the unit is OFF, switch it ON. If the unit will not run but the display is functioning, proceed to step 3. If the unit will not run and the display is also inoperative, go directly to the General Troubleshooting Guide.
Write down the set-points. Be aware that the initial key stroke may change the set-point by one degree increment or decrement.
Initiate Diagnostic Mode by pressing and holding either the COLDER key and the UNIT ON/OFF key. Record any Error Codes and temperature readings for each thermistor location. If error codes appear, go to the Error Code Troubleshooting Guide. If "EE" is displayed, it indicates a thermistor error, which cuts power to the compressor and fans.
Initiate Temperature Log Recall Mode by pressing and holding the desired compartment WARMER key and the UNIT ON/OFF key. Toggle through the indexes, recording temperatures for both compartments. Circle "BELL ON" or "SERVICE" indicators if they light up during an index. Observing logged temperatures helps identify warming/cooling trends, power interruptions ("BELL ON"), or unit shut-off ("SERVICE"). If double dashes (-- ) are displayed, the control board is defective.
Use the gathered information in conjunction with the General Troubleshooting Guide.

Wine Storage Thermistor Location Codes

THERMISTOR LOCATION	CODE
Upper Evaporator	UE
Lower Evaporator	LE
Upper Compartment	UP
Lower Compartment	LO

Note: Refer to the Temperature Log Index Chart on the last page of section 3 for index/time correlation.

Wine Storage Error Code Troubleshooting Guide

Error Codes indicate problems registered by specific components. They appear before temperature readings in Diagnostic Mode.

Instructions:

Initiate Diagnostic Mode by pressing and holding either COLDER key, then press the UNIT ON/OFF key, and release both keys.
Check for Error Codes on the display by toggling through readings using COLDER or WARMER keys.
If Error Codes appear, follow the Error Code Troubleshooting Guide. The left column lists codes, and the right column explains tests/actions.

Note: A "SERVICE" indicator will appear constant when Diagnostic Mode ends if error codes are logged. To clear them, correct the problem, ensure the unit is ON, then press and hold the bell key for 15 seconds. A short "beep" confirms clearing.

Wine Storage Error Code Table

CODE	INDICATION
05	Upper Cabinet Thermistor read open or shorted for 10+ seconds, or repeatedly read erratic temp's
06	Upper Evaporator Thermistor read open or shorted for 10+ seconds, or repeatedly read erratic temp's
07	Lower Cabinet Thermistor read open or shorted for 10+ seconds, or repeatedly read erratic temp's
08	Lower Evaporator Thermistor read open or shorted for 10+ seconds, or repeatedly read erratic temp's
10	Upper Cabinet Warm Temperature alarm
11	Upper Cabinet Cold Temperature alarm
12	Lower Cabinet Warm Temperature alarm
13	Lower Cabinet Cold Temperature alarm
15	Sealed System Fault (evap temperature cannot drop 5° in 5 minutes, 3 consecutive valve activations)

Wine Storage Thermistor Location Codes

MODELS 424-2, 427-2, 427R-2, 430-2

THERMISTOR LOCATION	CODE
Upper Evaporator	UE
Lower Evaporator	LE
Upper Compartment	UP
Lower Compartment	LO

427R-2 Refrigerator Error Code Troubleshooting Guide

Error Codes indicate problems registered by specific components. They appear before temperature readings in Diagnostic Mode.

Instructions:

Initiate Diagnostic Mode by pressing and holding the COLDER key, then press the UNIT ON/OFF key, and release both keys.
Check for Error Codes on the display by toggling through readings using COLDER or WARMER keys.
If Error Codes appear, follow the Error Code Troubleshooting Guide. The left column lists codes, and the right column explains tests/actions.

Note: If Error Codes appear with a flashing "SERVICE" annunciator prior to initiating Diagnostic Mode, the unit experienced excessive compressor run condition that may or may not be associated with the Error Codes displayed.

427R-2 Refrigerator Compartment Error Code Table

CODE	INDICATION
05	Refrig. cabinet thermistor read open or shorted for 10+ seconds, or repeatedly read erratic temp's
06	Refrig. evaporator thermistor read open or shorted for 10+ seconds, or repeatedly read erratic temp's
50	Excessive Refrigerator Compressor Run

Refrigerator Thermistor Location Codes

MODEL 427R-2 Only

THERMISTOR LOCATION	CODE
Refrigerator Compartment	Γ
Refrigerator Evaporator	E

General Troubleshooting Guide

Match the unit's complaint or problem description to the table of contents below. The left column lists the problem letter, the center column lists possible causes, and the right column provides tests and corrective actions.

Note: If the complaint involves warm or cold temperatures, complete a Temperature Problem Diagnostic Worksheet first.

Wine Storage Troubleshooting Guide Table of Contents

Ltr	Problem Description	Page #
A.	"SERVICE" Flashing	7-11
B.	Warm Temperature in Both Wine Storage Compartments	7-11
C.	Warm Temperature in Only One Wine Storage Compartment	7-12
D.	Actual vs. Displayed Temperature Over 10° Different	7-13
E.	Actual vs. Displayed Temperature Less Than 10° Different	7-13
F.	Excessively Cold Temperatures in Both Wine Storage compartments	7-13
G.	Excessively Cold Temperatures in Only One Wine Storage compartment	7-13
H.	Lights Stay ON	7-13
I.	No Lights	7-13
J.	Control Panel Keys Malfunctioning	7-14
K.	No LED's	7-14
L.	All LED's Lit	7-14
M.	Same LED Segments Missing from Both Display Windows	7-14
N.	LED Segments Missing from Only One Display Window	7-14
O.	Door / Unit Un-level	7-14

427R-2 Refrigerator Section Troubleshooting Guide Table of Contents

Ltr	Problem Description	Page #
P.	"EE" Displayed in place of Refrigerator Temperature with "SERVICE" Flashing	7-15
Q.	Warm or Normal Temperatures Displayed with "SERVICE” Alone Flashing	7-15
R.	Warm or Normal Temperatures Displayed with non-flashing “SERVICE" Displayed	7-15
S.	Erratic Temperatures with or without “SERVICE" Flashing	7-15
T.	Warm Refrigerator Temperatures, "SERVICE" not displayed or Flashing	7-15
U.	Product Temperature 10° or More Colder than Displayed Temperature	7-16
V.	1. "Extremely" Cold Temperatures Displayed (1° to 7° in Refrigerator)	7-16
	2. If outside US - "Extremely" Warm Temperatures Displayed (34° to 45° in Refrigerator)	7-16
W.	No LCD	7-16
Χ.	No Lights	7-17
Y.	Lights Stay ON when Drawers Closed - (May be Accompanied by Drawer Ajar Alarm Bell)	7-17
Z.	Drawers Not Able to Close Completely	7-17
AA.	Drawers Uneven	7-17

Additional sections include: Sealed System Diagnostic Tables, Wine Storage Membrane Switch Ribbon Cable Test, and Model 427R Refrigerator Membrane Switch Ribbon Cable Test.

General Troubleshooting Guide - Detailed Problems and Solutions

A. "SERVICE" Flashing

Possible Cause: Refer to Error Code Troubleshooting Guide.

B. Warm Temperature in Both Wine Storage Compartments

PROBLEM	POSSIBLE CAUSE	TEST / ACTION
B. WARM TEMPERATURE IN BOTH WINE STORAGE COMPARTMENTS	Control Set Too Warm	Check/adjust set-points. Adjust set-points COLDER.
	Unit in Showroom Mode	Adjust set-points colder, listen for compressor & condenser fan operation. If they do not run, switch unit OFF, then press and hold upper COLDER & WARMER keys while pressing UNIT ON/OFF key.
	Unit Recently Energized	Allow time for unit to pull down.
	Unit Recently Stocked with Wine	Instruct customer.
	High Room Ambient	Instruct Customer that unit performs best between 60°F / 16°C - 90°F / 32°C.
	Door Ajar	a. Adjust wine rack. b. See Door Adjustment procedure in section 2 of this manual. c. Check hinges. Replace if defective.
	Condenser Air Flow / Fan Fault	a. Check/clean condenser. b. Tighten blade or move obstruction. c. Check fan motor operation. Check fan motor electrical connections back to compressor. Check for 115V AC from fan motor to compressor. Reconnect or repair wires, or replace motor if defective.
	Evaporator Fan / Fan Circuit Fault	a. Check fan switch electrical connections. Check for 115V AC to and from switch. Reconnect or replace switch if defective. b. Check for 115V AC at J3 on control board. (NOTE: Unit must be running and not in Showroom Mode) If no power, replace board.
	No Power from Control Board to Compressor	Initiate Manual Valve Activation Mode, check for 115V AC at E2 on the control board. If no power, replace board.
	Compressor Fault	a. Check integrity of compressor electricals. Check continuity back to control board. Check for 115V AC at E2 on control board. Correct wiring problems or replace compressor electricals if defective. If no power between at E2, replace control board. b. Check AMP draw on compressor. If high by 15% or more, replace compressor.
	Sealed System Leak or Restriction	SEE SEALED SYSTEM DIAGNOSTIC INFORMATION

C. Warm Temperature in Only One Wine Storage Compartment

PROBLEM	POSSIBLE CAUSE	TEST / ACTION
C. WARM TEMPERATURE IN ONLY ONE WINE STORAGE COMPARTMENT	Control Set Too Warm	Check/adjust set-points.
	Unit Recently Energized	Allow time for unit to pull down.
	Unit Recently Stocked with Wine	Instruct customer.
	High Room Ambient	Instruct Customer that unit performs best between 60°F / 16°C - 90°F / 32°C.
	Door Ajar	a. Adjust wine rack. b. See Door Adjustment procedure in section 2 of this manual. c. Check hinges. Replace if defective.
	Thermistor Fault	a. Move to correct location. b. Initiate Diagnostic Mode. If "EE" is displayed in place of evap temp, check electrical connections back to J2 on control board. Repair wiring or connections. c. Check thermistor ohms = 30,000 - 33,000 at 32°F / 0°C. Replace if defective.
	Condenser Air Flow / Fan Fault	a. Check/clean condenser. b. Tighten blade or move obstruction. c. Check fan motor operation. Check fan motor electrical connections back to compressor. Check for 115V AC from fan motor to compressor. Reconnect or repair wires, or replace motor if defective.
	Evaporator Fan / Fan Circuit Fault	a. Check fan blade position. Reposition blade or move obstructions. b. Check fan switch electrical connections. Check for 115V AC to and from switch. Reconnect or replace switch if defective. c. Check fan motor electrical connections, and check for 115V AC to motor. Repair connections, replace motor if defective. d. Check for 115V AC from J3 on control board. (NOTE: Unit must be running and not in Showroom Mode) If no power, replace board.
	Refrigerant Valve Fault	a. Initiate Manual Valve Activation Mode. 1. If valve inoperative: Check electrical connections. Check solenoid resistance for 680 ± 10% ohms. Replace if defective. 2. Toggle through temp readings, if opposite evap temp drops, switch electrical connections. b. Initiate Manual Valve Activation Mode for one side, then the other, while observing evap temps. If only one side of valve activates, replace valve.

D. Actual vs. Displayed Temperature Over 10° Different

PROBLEM	POSSIBLE CAUSE	TEST / ACTION
D. ACTUAL VS. DISPLAYED TEMPERATURE OVER 10° DIFFERENT	Wrong Units of Measure Selected, (Fahrenheit - °F vs. Celsius - °C)	Initiate Temperature Units Selection Mode to check units of measure (°F or °C) selected.
	Compartment Thermistor Fault (Misread), or Control Board Fault	Check thermistor ohms = 30,000 - 33,000 at 32°F / 0°C. Replace if defective. If thermistor is OK, replace control board.

E. Actual vs. Displayed Temperature Less Than 10° Different

PROBLEM	POSSIBLE CAUSE	TEST / ACTION
E. ACTUAL VS. DISPLAYED TEMPERATURE LESS THAN 10° DIFFERENT	Control Board DC Offset Out of Adjustment	Contact Factory for DC Offset Adjustment Procedure.

F. Excessively Cold Temperatures in Both Wine Storage Compartments

PROBLEM	POSSIBLE CAUSE	TEST / ACTION
F. EXCESSIVELY COLD TEMPERATURES IN BOTH WINE STORAGE COMPARTMENTS	Room Temperature Below Set-Point	Instruct Customer.
	Control Set Too Cold	Check set-points. Adjust set-points WARMER.
	Door Ajar	a. Adjust wine rack. b. See Door Adjustment procedure in section 2 of this manual. c. Check hinges. Replace if defective.
	Compartment Thermistor Fault (Misread), or Control Board Fault	Check thermistor ohms = 30,000 - 33,000 at 32°F / 0°C. Replace if defective. If thermistor is OK, replace control board.

G. Excessively Cold Temperatures in Only One Wine Storage Compartment

PROBLEM	POSSIBLE CAUSE	TEST / ACTION
G. EXCESSIVELY COLD TEMPERATURES IN ONLY ONE WINE STORAGE COMPARTMENT	Room Temperature Below Set-Point	Instruct Customer.
	Control Set Too Cold	Check set-point. Adjust set-points WARMER.
	Door Ajar	a. Adjust wine rack. b. See Door Adjustment procedure in section 2 of this manual. c. Check hinges. Replace if defective.
	Refrigerant Valve Stuck	Initiate Manual Valve Activation Mode for one side, then the other, while observing evap temps. If only one side of valve activates, replace valve.

H. Lights Stay ON

PROBLEM	POSSIBLE CAUSE	TEST / ACTION
H. LIGHTS STAY ON	Display Lighting Activated (ON 100%)	Press & release LIGHTS ON/OFF key.
H. LIGHTS STAY ON	Fan & Light Switch Wiring Crossed	Check wiring at fan & light switch, and at control board. Rewire if incorrect.
	Light Switch Malfunction	Press & release LIGHTS ON/OFF key, then depress light switch. Repeat steps. If no effect, replace switch.

I. No Lights

PROBLEM	POSSIBLE CAUSE	TEST / ACTION
I. NO LIGHTS	Unit in Sabbath Mode	Press & release UNIT ON/OFF key.
	Light Switch Disconnected or Malfunctioning	Check switch operation and electrical connections. Check for 115V AC to and from switch. Reconnect wires or replace switch if defective.
	Light Strip Burned-out	If power from switch, replace light strip.
	No Power from Control Board	Check for 115V AC at E3 of control board. If no power, replace board.

J. Control Panel Keys Malfunctioning

PROBLEM	POSSIBLE CAUSE	TEST / ACTION
J. CONTROL PANEL KEYS MALFUNCTIONING	Control Panel Ribbon Cable Plugged in Wrong	Check control panel ribbon cable at control panel (silver area of terminal away from control board). Plug in correctly if incorrect.
J. CONTROL PANEL KEYS MALFUNCTIONING	Control Panel or Ribbon Cable Defective (OR) No Signal Read at Control Board	SEE CONTROL PANEL TEST PROCEDURE AT BACK OF TROUBLESHOOTING GUIDE SECTION.

K. No LED's

PROBLEM	POSSIBLE CAUSE	TEST / ACTION
K. NO LED's	Unit Switched OFF	Press UNIT ON/OFF key.
	LED Ribbon Cable Plugged in Wrong	Check LED ribbon cable. Plug in correctly if incorrect.
	No Data from Control Board	Replace Control Board.

L. All LED's Lit

PROBLEM	POSSIBLE CAUSE	TEST / ACTION
L. ALL LED's LIT	Bad Data from Control Board	Replace Control Board.

M. Same LED Segments Missing from Both Display Windows

PROBLEM	POSSIBLE CAUSE	TEST / ACTION
M. SAME LED SEGMENTS MISSING FROM BOTH DISPLAY WINDOWS	Bad Data from Control Board	Replace Control Board.

N. LED Segments Missing from Only One Display Window

PROBLEM	POSSIBLE CAUSE	TEST / ACTION
N. LED SEGMENTS MISSING FROM ONLY ONE DISPLAY WINDOWS	Bad LED Board in Control Panel	Replace Control Panel Assembly.

O. Door / Unit Un-level

PROBLEM	POSSIBLE CAUSE	TEST / ACTION
O. DOOR / UNIT UN-LEVEL	SEE SECTION 2 OF THIS MANUAL	SEE SECTION 2 OF THIS MANUAL

P. "EE" Displayed in place of Refrigerator Temperature with "SERVICE" Flashing

PROBLEM	POSSIBLE CAUSE	TEST / ACTION
P. "EE" Displayed in place of Refrigerator Temperature with "SERVICE" Flashing	Refrigerator Compartment Thermistor Disconnected, Shorted, or misread	Check refrigerator compartment thermistor electrical connections from thermistor to control board. Reconnect / repair connections. Check resistance of refrigerator compartment thermistor for 30,000 to 33,000 ohms at 32°F. Replace if defective.
	Excessive Compressor Run	Initiate Diagnostic Mode and see Error Code Troubleshooting Guide.

Q. Warm or Normal Temperatures Displayed with "SERVICE" Alone Flashing

PROBLEM	POSSIBLE CAUSE	TEST / ACTION
Q. Warm or Normal Temperatures Displayed with "SERVICE" Alone Flashing	Evaporator Thermistor Disconnected, Shorted, or misread	Check evaporator thermistor electrical connections from thermistor to control board. Reconnect / repair connections. Check resistance of evaporator thermistor for 30,000 to 33,000 ohms at 32°F. Replace if defective.

R. Warm or Normal Temperatures Displayed with non-flashing "SERVICE" Displayed

PROBLEM	POSSIBLE CAUSE	TEST / ACTION
R. Warm or Normal Temperatures Displayed with non-flashing "SERVICE" Displayed	Error Codes Observed in Diagnostic Mode, but not Cleared from Memory	Enter diagnostic mode to observe error codes. See Error Code Troubleshooting Guide. Verify unit was repaired for error codes displayed. Press and hold alarm key for 15 seconds to clear error codes.

S. Erratic Temperatures with or without "SERVICE" Flashing

PROBLEM	POSSIBLE CAUSE	TEST / ACTION
S. Erratic Temperatures with or without "SERVICE" Flashing	Control Board Configured for Wrong Model	Initiate Manual Model Configuration Mode and reconfigure to correct model.

T. Warm Refrigerator Temperatures, "SERVICE" not displayed or Flashing

PROBLEM	POSSIBLE CAUSE	TEST / ACTION
T. Warm Refrigerator Temperatures, "SERVICE" not displayed or Flashing	No Power to Unit	Check power to unit, plug unit in or switch supply circuit breaker ON.
	Unit Switched OFF	Check for "OFF" displayed at LCD. If off, press UNIT ON/OFF key.
	Unit in Show Room Mode	Press UNIT ON/OFF key to OFF, then press and hold WARMER & COLDER keys, and press UNIT ON/OFF key.
	Control Set Too High	Check set-point. If high, adjust.
	Warm Food Load	Check contents of freezer for warm food load. Instruct customer.
	High Room Ambient	Instruct customer unit performs best between 60°F(16°C) and 90°F(32°C).
	Drawer Ajar	a. Move obstruction. b. Trip drawer closer forward.
	Faulty Light Switch	Check operation of light switches, lights off when switch is depressed. Replace switch if defective. (NOTE: Two light switches in unit)
	Refrigerator Compartment Fan Fault	a. Move obstruction or reposition blade. b. Check electrical connections & continuity from control board to motor. Reconnect / repair, use conduits. c. Check for 115V AC from control board to fan motor. Replace control board if defective, or Replace motor if defective.
	Compartment Thermistor Disconnected, Shorted, or misread	Check refrigerator evaporator thermistor electrical connections from thermistor to control board. Reconnect / repair connec- tions. Check resistance of refrigerator evaporator thermistor for 30,000 to 33,000 ohms at 32°F. Replace if defective.

U. Product Temperature 10° or More Colder than Displayed Temperature

PROBLEM	POSSIBLE CAUSE	TEST / ACTION
U. Product Temperature 10° or More Colder than Displayed Temperature	Compartment Thermistor Misread	Check resistance of compartment thermistor for 30,000 to 33,000 ohms at 32°F. Replace if defective.

V. "Extremely" Cold Temperatures Displayed

PROBLEM	POSSIBLE CAUSE	TEST / ACTION
V. 1. "Extremely" Cold Temperatures Displayed (1° to 7° in Refrigerator)	Control Set to Display Celsius	1. Change temperature units of measure to Fahrenheit. Switch unit OFF, then ON, then press & hold Bell key and UNIT ON/OFF key for 10 seconds.
	2. If outside US - Control Set to Display Fahrenheit	2. If Outside US - Change temperature units of measure to Celsius. Switch unit OFF, then ON, then press & hold Bell key and UNIT ON/OFF key for 10 seconds.

W. No LCD

PROBLEM	POSSIBLE CAUSE	TEST / ACTION
W. No LCD	Unit in Sabbath Mode	Exit Sabbath Mode, press UNIT ON/OFF key.
W. No LCD	Display Wire Harness Disconnected or Faulty	Check display wire harness and connections, including wires behind refrigerator duct cover. Reconnect, repair, replace bad wiring.
	Control Panel Assembly Defective (OR) No Signal Read at Control Board	See Membrane Switch/Ribbon Cable Test Procedures. If membrane switch fails any test, replace entire control panel assembly. If switch passes all tests, replace control board.

X. No Lights

PROBLEM	POSSIBLE CAUSE	TEST / ACTION
X. No Lights	No power to unit	Check / correct power supply to unit.
	Unit switched OFF	Switch unit ON, press UNIT ON/OFF key.
	Unit in Sabbath Mode	Exit Sabbath Mode, press UNIT ON/OFF key.
	Defective or loose light bulb(s)	Install a known good light bulb.
	Light Switch Disconnected or Defective	Check wire connections at light switch. Reconnect/repair. Check for 115V AC to and from light switch. Replace switch if defective.
	Lighting System Wiring Disconnected or Defective	Check continuity from light sockets to switch. Reconnect/repair or replace defective components.
	No Power From Control Board	Check for 115V AC from control board. Replace board if defective. (NOTE: See Unit in Sabbath Mode above.)

Y. Lights Stay ON when Drawers Closed

PROBLEM	POSSIBLE CAUSE	TEST / ACTION
Y. Lights Stay ON when Drawers Closed - (May be Accompanied by /Drawer Ajar Alarm Bell)	Door or Drawer Ajar	a. Food product obstruction b. Drawer closer tripped backwards
	Faulty Light Switch	Check operation of light switches, lights off when switch is depressed. Replace switch if defective. (NOTE: Two light switches in unit)

Z. Drawers Not Able to Close Completely

PROBLEM	POSSIBLE CAUSE	TEST / ACTION
Z. Drawers Not Able to Close Completely	Food Product Obstruction	Move obstruction.
	Drawer Closer Tripped Backwards	Trip drawer closer forward.

AA. Drawers Uneven

PROBLEM	POSSIBLE CAUSE	TEST / ACTION
AA. Drawers Uneven	Improper Drawer Panel Installation	The drawers are non-adjustable. Instead, the drawer panels must be adjusted if there is an alignment problem. Refer to the Installation Manual and/or installation video for panel installation and adjustment.
AA. Drawers Uneven	Unit Not Level	Check levelness of unit. If un-level, turn front leveling legs counterclockwise to raise front or clockwise to lower it. Rear levelers are adjusted from front of base by turning adjusting screw clockwise to raise rear or counterclockwise to lower it. Refer to the Installation Manual and/or installation video for complete installation and leveling instructions.

Sealed System Diagnostic Information

The temperature/pressure table and normal operating pressures are for reference only. Actual correlations may differ due to variations in thermistor location, set-points, refrigeration cycle stage, ambient temperature, and gauge calibration.

Note: Before accessing the sealed system, rule out mechanical and electrical components. Use solder-on process valves. The valve assembly (includes high-side filter-drier) must be replaced when servicing the sealed system.

Temperature / Low-Side Pressure Correlation

Temperature	Pressure
-30°F / -34°C	10" Vac / -.69 Bar
-25°F / -32°C	7" Vac / -.48 Bar
-20°F / -29°C	4" Vac / -.28 Bar
-15°F / -26°C	0" Vac / 0 Bar
-10°F / -23°C	2 Psi/.14 Bar
-5°F / -21°C	4 Psi/.28 Bar
0°F / -18°C	7 Psi/.48 Bar
5°F / -15°C	9 Psi /.62 Bar
10°F / -12°C	12 Psi/.83 Bar
15°F / -9°C	15 Psi/ 1.03 Bar
20°F / -7°C	18 Psi / 1.24 Bar
25°F / -4°C	22 Psi / 1.51 Bar
30°F / -1°C	26 Psi / 1.79 Bar
35°F / 2°C	30 Psi / 2.07 Bar
40°F / 4°C	35 Psi / 2.41 Bar
45°F / 7°C	40 Psi / 2.76 Bar
50°F / 10°C	45 Psi / 3.10 Bar
55°F / 13°C	51 Psi / 3.52 Bar
60°F / 16°C	57 Psi / 3.93 Bar
65°F / 18°C	64 Psi / 4.41 Bar
70°F / 21°C	71 Psi / 4.90 Bar
75°F / 24°C	78 Psi / 5.38 Bar

Normal Operating Pressures (70°F/21°C Ambient / 38°F/ 3°C Set-Point)

Model	Normal Low Side Pressures	Normal High Side Pressures
424-2	0-12 PSI to 30-45 PSI	75 psi to 120 psi
427-2	0-12 PSI to 30-45 PSI	75 psi to 120 psi
427R-2 (Wine)	0-12 PSI to 30-45 PSI	75 psi to 120 psi
427R-2 (Ref)	0-12 PSI to 30-45 PSI	75 psi to 120 psi
430-2	0-12 PSI to 30-45 PSI	75 psi to 120 psi

Pressure Indications

If low side pressure is	& high side pressure is	possible problem is
NORMAL	NORMAL	MECHANICAL (see General Troubleshooting Guide)
LOW	LOW	LEAK
LOW	HIGH	RESTRICTION
HIGH	LOW	INEFFICIENT COMPRESSOR
HIGH	HIGH	OVER CHARGE

Membrane Switch / Ribbon Cable Test Procedures

The membrane switch is part of the control panel assembly and provides input functions to the electronic control system.

Note: To perform continuity checks, disconnect the ribbon cable from the control board. The wires are exposed at the back of the terminal housing. Use an Ohm Meter to check continuity at these exposed points/pins. Pin #1 is at the top of the terminal housing, closest to the arrow.

Continuity Checks:

Pressing no keys: Check continuity across all pin combinations. There should be no continuity.
UNIT ON/OFF key pressed: Continuity across pins #4 & #6 only.
Lower wine storage COLDER key pressed: Continuity across pins #2 & #3 only.
Lower wine storage WARMER key pressed: Continuity across pins #3 & #4 only.
Upper wine storage COLDER key pressed: Continuity across pins #2 & #6 only.
Upper wine storage WARMER key pressed: Continuity across pins #5 & #7 only.
LIGHTS ON/OFF key pressed: Continuity across pins #5 & #6 only.
Alarm bell key pressed: Continuity across pins #3 & #7 only.

Note: If the membrane switch fails any test, replace the control panel assembly. If all tests pass and the unit is still inoperable, replace the control board.

Diagram Description: Figure 7-1 illustrates the Control Panel Assembly, showing the membrane switch keys (WINE STORAGE, COLDER, WARMER, LIGHTS ON/OFF, UNIT ON/OFF, BELL ON/OFF, SERVICE) and the ribbon cable. It also indicates Pin #1 at the top of the terminal housing and exposed points/pins on the back side of the housing.

Model 427R-2 Refrigerator Membrane Switch / Ribbon Cable Test Procedure

If the refrigerator control panel assembly is suspect, continuity tests should be performed at the membrane switch ribbon cable terminal housing. Remove the control panel assembly and place it on a solid surface. Disconnect the ribbon cable from the control panel PC board.

How To Identify Pin 1 on Terminal Housing:

If terminal housing is BLUE, pin 1 is closest to the arrow on the housing.
If terminal housing is BLACK, check for continuity between the first and third pins at each end of the housing while pushing the refrigerator WARMER key. If continuity exists, pin 1 is at that end.

700BCI-3 Membrane Switch/Ribbon Cable Test Procedure:

Press no keys on the membrane switch. Check for continuity between all pin combinations. With no keys pressed, there should be no continuity between any pins.
Press UNIT ON/OFF key: Continuity across pins 3 & 4.
Press Door Ajar Alarm ON/OFF key: Continuity across pins 2 & 4.
Press Refrigerator WARMER key: Continuity across pins 4 & 5.
Press Refrigerator COLDER key: Continuity across pins 1 & 3.

Note: If any of the tests show failure, replace the entire control panel assembly.

Diagram Description: Figure 7-2 shows the Refrigerator Control Panel Assembly with a cut-away view to illustrate the ribbon cable and terminal housing. It highlights the location of the Membrane Switch in the Control Panel Assembly and the Terminal Housing, noting how to identify Pin 1.

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SUB-ZERO Wine Storage (400-2) Series Troubleshooting Guide

Troubleshooting Guides Overview

Temperature Problem Diagnostic Worksheet

Wine Storage Thermistor Location Codes

Wine Storage Error Code Troubleshooting Guide

Wine Storage Error Code Table

Wine Storage Thermistor Location Codes

427R-2 Refrigerator Error Code Troubleshooting Guide

427R-2 Refrigerator Compartment Error Code Table

Refrigerator Thermistor Location Codes

General Troubleshooting Guide

Wine Storage Troubleshooting Guide Table of Contents

427R-2 Refrigerator Section Troubleshooting Guide Table of Contents

General Troubleshooting Guide - Detailed Problems and Solutions

A. "SERVICE" Flashing

B. Warm Temperature in Both Wine Storage Compartments

C. Warm Temperature in Only One Wine Storage Compartment

D. Actual vs. Displayed Temperature Over 10° Different

E. Actual vs. Displayed Temperature Less Than 10° Different

F. Excessively Cold Temperatures in Both Wine Storage Compartments

G. Excessively Cold Temperatures in Only One Wine Storage Compartment

H. Lights Stay ON

I. No Lights

J. Control Panel Keys Malfunctioning

K. No LED's

L. All LED's Lit

M. Same LED Segments Missing from Both Display Windows

N. LED Segments Missing from Only One Display Window

O. Door / Unit Un-level

P. "EE" Displayed in place of Refrigerator Temperature with "SERVICE" Flashing

Q. Warm or Normal Temperatures Displayed with "SERVICE" Alone Flashing

R. Warm or Normal Temperatures Displayed with non-flashing "SERVICE" Displayed

S. Erratic Temperatures with or without "SERVICE" Flashing

T. Warm Refrigerator Temperatures, "SERVICE" not displayed or Flashing

U. Product Temperature 10° or More Colder than Displayed Temperature

V. "Extremely" Cold Temperatures Displayed

W. No LCD

X. No Lights

Y. Lights Stay ON when Drawers Closed

Z. Drawers Not Able to Close Completely

AA. Drawers Uneven

Sealed System Diagnostic Information

Temperature / Low-Side Pressure Correlation

Normal Operating Pressures (70°F/21°C Ambient / 38°F/ 3°C Set-Point)

Pressure Indications

Membrane Switch / Ribbon Cable Test Procedures

Model 427R-2 Refrigerator Membrane Switch / Ribbon Cable Test Procedure

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