Troubleshooting Guides

MODEL UW-24 SUB-ZERO

Troubleshooting Guides

This section of the manual contains:

Temperature Problem Diagnostic Worksheets
Error Code Tables and the Error Code Troubleshooting Guides
General Troubleshooting Guide
Membrane Switch/Ribbon Cable Test Procedures
Sealed System Diagnostic Tables
Fan Relay Continuity Tests

Temperature Problem Diagnostic Worksheet

The Diagnostic Worksheets on the following three pages are designed to help identify the cause of temperature problems in a wine storage unit. To fill out the worksheet, familiarity with Diagnostic Mode and Temperature Log Recall Mode is required (See section 2 of this manual).

Follow the steps below and fill out a diagnostic worksheet before referencing the General Troubleshooting Guide.

Write down the temperatures shown on the display.
1. If unit is OFF, switch unit ON and go to step #2 below.
2. If unit does not run, but display is functioning, go to step #3 below.
NOTE: “EE” displayed in place of either compartment temperature indicates a compartment thermistor error. Thermistor errors cause power to the compressor and fans to be cut.
1. If unit does not run and display does not operate, go directly to General Troubleshooting Guide.
Write down the set-points, keep in mind that the initial key stroke does not change the set-point on the UW-24.
Initiate Diagnostic Mode by pressing and holding either COLDER key and the POWER key, then write down any Error codes that may appear and the temperature readings for each thermistor location. (See Thermistor Location Code Table at right.)
1. If error codes appear, go directly to Error Code Troubleshooting Guide.
2. If “EE” is displayed in place of temperature, this indicates a thermistor error in that location.
Initiate Temperature Log Recall Mode by pressing and holding the desired compartment WARMER key and the POWER key, then toggle through the indexes, writing down the temperature of each index for both compartments. If the ALARM or SERVICE indicators light up during an index, circle it on the worksheet.
1. By observing the temperatures logged, it is possible to see if any warming or cooling trends occurred, whether this trend was in one or both compartments, and if there was a power interruption (ALARM illuminated), or that the unit was switched OFF (SERVICE illuminated).
2. If double dashes ( - - ) are displayed, the control board is defective.
NOTE: To see the index/time correlation, refer to the Temperature Log Index Chart on last page of section 2 of this manual.
Use the information gathered on the worksheet 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

TEMPERATURE PROBLEM DIAGNOSTIC WORKSHEET

Temperature Displayed: Lower ____ Upper ____

Set-Point: Lower ____ Upper ____

Diagnostic Mode Thermistor Readings: EC (Error Codes) ____ UE (Upper Evap) ____ LE (Lower Evap) ____ UP (Upper Cmprt) ____ LO (Lower Cmprt) ____

Index	Logged Temp.		Indicator Lit (Circle below if present)	Index	Logged Temp.		Indicator Lit (Circle below if present)
Index	Lower	Upper	Indicator Lit (Circle below if present)	Index	Lower	Upper	Indicator Lit (Circle below if present)
1			ALARM / SERVICE	33			ALARM / SERVICE
2			ALARM / SERVICE	34			ALARM / SERVICE
3			ALARM / SERVICE	35			ALARM / SERVICE
4			ALARM / SERVICE	36			ALARM / SERVICE
5			ALARM / SERVICE	37			ALARM / SERVICE
6			ALARM / SERVICE	38			ALARM / SERVICE
7			ALARM / SERVICE	39			ALARM / SERVICE
8			ALARM / SERVICE	40			ALARM / SERVICE
9			ALARM / SERVICE	41			ALARM / SERVICE
10			ALARM / SERVICE	42			ALARM / SERVICE
11			ALARM / SERVICE	43			ALARM / SERVICE
12			ALARM / SERVICE	44			ALARM / SERVICE
13			ALARM / SERVICE	45			ALARM / SERVICE
14			ALARM / SERVICE	46			ALARM / SERVICE
15			ALARM / SERVICE	47			ALARM / SERVICE
16			ALARM / SERVICE	48			ALARM / SERVICE
17			ALARM / SERVICE	49			ALARM / SERVICE
18			ALARM / SERVICE	50			ALARM / SERVICE
19			ALARM / SERVICE	51			ALARM / SERVICE
20			ALARM / SERVICE	52			ALARM / SERVICE
21			ALARM / SERVICE	53			ALARM / SERVICE
22			ALARM / SERVICE	54			ALARM / SERVICE
23			ALARM / SERVICE	55			ALARM / SERVICE
24			ALARM / SERVICE	56			ALARM / SERVICE
25			ALARM / SERVICE	57			ALARM / SERVICE
26			ALARM / SERVICE	58			ALARM / SERVICE
27			ALARM / SERVICE	59			ALARM / SERVICE
28			ALARM / SERVICE	60			ALARM / SERVICE
29			ALARM / SERVICE	61			ALARM / SERVICE
30			ALARM / SERVICE	62			ALARM / SERVICE
31			ALARM / SERVICE	63			ALARM / SERVICE
32			ALARM / SERVICE	64			ALARM / SERVICE

Wine Storage Error Code Troubleshooting Guide Instructions

Error Codes indicate problems logged by specific components. If error codes are logged, they appear before temperature readings while in Diagnostic Mode and they can be toggled through with the temperature readings.

With the unit ON, initiate Diagnostic Mode by pressing and holding either COLDER key, then press the POWER key, then release both keys.
Check for Error Codes on the display, making sure to toggle through all possible readings by pressing either COLDER key. (See Error Code Table Below)
If Error Codes appear, reference the Error Code Troubleshooting Guide on the next page.
1. The left column of the Error Code Troubleshooting Guide lists the error codes.
2. The right column of the Error Code Troubleshooting Guide explains what tests and/or corrective actions to perform.

NOTE: If error codes are observed, the SERVICE indicator appears constant when Diagnostic Mode ends, indicating error codes are logged. To clear this and the error codes from the software memory, the problem must be corrected and the unit must be ON; then press and hold the ALARM key for 15 seconds. The control emits a quick “beep” when the SERVICE indicator and error codes are cleared.

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	Lower Cabinet Thermistor read open or shorted for 10+ seconds, or repeatedly read erratic temp's
07	Upper Evaporator 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

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

WINE STORAGE ERROR CODE TROUBLESHOOTING GUIDE

Error Code	Test / Action
EC 05	a. Check upper compartment thermistor electrical connections and continuity from thermistor to J2 on control board. Reconnect / repair connections. b. Check upper compartment thermistor for 30,000 to 33,000 ohms at 32°F. Replace thermistor if defective.
EC 06	a. Check upper compartment evaporator thermistor electrical connections and continuity from thermistor to J2 on control board. Reconnect / repair connections. b. Check upper evaporator thermistor for 30,000 to 33,000 ohms at 32°F. Replace thermistor if defective.
EC 07	a. Check lower compartment thermistor electrical connections and continuity from thermistor to J2 on control board. Reconnect / repair connections. b. Check lower compartment thermistor for 30,000 to 33,000 ohms at 32°F. Replace thermistor if defective.
EC 08	a. Check lower compartment evaporator thermistor electrical connections and continuity from thermistor to J2 on control board. Reconnect / repair connections. b. Check lower evaporator thermistor for 30,000 to 33,000 ohms at 32°F. Replace thermistor if defective.
EC 10 or EC 12	a. Check room ambient temperature. Unit performs best between 60°F - 90°F. b. Check for door obstructions, door seal and door adjustment issues; Remove obstruction, align door. c. Check switch depressor; Reposition or replace. d. Check cleanliness of condenser; Clean condenser. e. Check for obstructions at appropriate compartment fan blade; Remove obstruction. f. Check appropriate compartment evaporator fan blade spacing. Adjust if needed. g. Check appropriate fan motor and its electrical connections; Repair or replace. h. Check door switch and its electrical connections; Repair or replace. i. Check resistance of appropriate compartment thermistor for 30,000 to 33,000 ohms at 32°F. Replace if defective. j. Initiate manual valve activation mode for appropriate compartment: 1. Check for proper voltage from J3 on board to appropriate evaporator fan motor. Replace or repair defective components. 2. If opposite evaporator temperature drops, check for proper wiring at valve; repair wire connections. If wiring is correct, replace valve assembly. k. Check AMP draw of compressor. If high by 15% or more, replace compressor. l. Check sealed system for leaks; Repair replace defective parts.
EC 11 or EC 13	a. Check room ambient temperature. Unit performs best between 60°F - 90°F. b. Check for door obstructions, door seal and door adjustment issues; Remove obstruction, align door. c. Check appropriate compartment thermistor electrical connections and continuity from thermistor to J2 on control board. Reconnect / repair connections. d. Check resistance of appropriate compartment thermistor for 30,000 to 33,000 ohms at 32°F. Replace if defective.
EC 15	a. Initiate manual valve activation mode for upper compartment: 1. Check for proper voltage from J3 on board to appropriate evaporator fan motor. Replace or repair defective components. 2. If lower evaporator temperature drops, check for proper wiring at valve; repair wire connections. If wiring is correct, replace valve assembly. b. Initiate manual valve activation mode for lower compartment: 1. Check for proper voltage from J3 on board to appropriate evaporator fan motor. Replace or repair defective components. 2. If upper evaporator temperature drops, check for proper wiring at valve; repair wire connections. If wiring is correct, replace valve assembly. c. Check AMP draw of compressor. If high by 15% or more, replace compressor. d. Check sealed system for leaks, or restrictions; Repair replace defective parts.

NOTE: After repairs, always clear Error Codes by pressing ALARM key for 15 seconds.

General Troubleshooting Guide

The Table of Contents below indicates how the General Trouble Shooting Guide is arranged.

As close as possible, match the complaint, or description of the problem the unit is experiencing with those in the table of contents below.
To the left of the problem description, take note of the letter.
Locate that letter in the left column of the General Troubleshooting Guide.
1. In the center column of the General Troubleshooting Guide is a list of possible causes for the problem.
2. The information in the right column explains what tests and/or corrective actions to perform.

NOTES:

If the complaint, or problem is warm temperatures, or temperatures too cold, in a wine storage compartment, be sure to complete a Temperature Problem Diagnostic Worksheet on the preceding pages before continuing.
All key strokes necessary to help in diagnosing a problem are explained in section 2 of this manual.

Wine Storage Troubleshooting Guide Table of Contents

Ltr	Problem Description	Page #
A.	SERVICE Flashing	6-9
B.	Warm Temperature in Both Wine Storage Compartments	6-9
C.	Warm Temperature in Only One Wine Storage Compartment	6-10
D.	Actual vs. Displayed Temperature Over 10° Different	6-11
E.	Actual vs. Displayed Temperature Less Than 10° Different	6-11
F.	Excessively Cold Temperatures in Both Wine Storage compartments	6-11
G.	Excessively Cold Temperatures in Only One Wine Storage compartment	6-11
H.	Lights Stay On	6-11
I.	No Lights	6-12
J.	Control Panel Keys Malfunctioning	6-12
K.	No LED's	6-12
L.	All LED's Lit	6-12
M.	Same LED Segments Missing from Both Display Windows	6-12
N.	LED Segments Missing from Only One Display Window	6-12
O.	Door / Unit Un-level	6-12

General Troubleshooting Guide Table

PROBLEM	POSSIBLE CAUSE	TEST / ACTION
A. SERVICE FLASHING	See Error Code Troubleshooting Guide	See Error Code Troubleshooting Guide
B. WARM TEMPERATURE IN BOTH WINE STORAGE COMPARTMENTS	Control Set Too Warm Unit in Showroom Mode Unit Recently Energized Unit Recently Stocked with Wine High Room Ambient Door Ajar a. Wine Rack Obstruction b. Door out of Adjustment c. Door or Cabinet Hinge Problem Condenser Air Flow / Fan Fault a. Dirty Condenser b. Fan Blade Loose or Obstructed c. Fan Motor Disconnected or Malfunctioning Evaporator Fan Circuit Fault a. Door Switch Disconnected or Malfunctioning b. No Power from Control Board No Power from Control Board to Compressor Compressor Fault a. Compressor Electricals Disconnected or Malfunctioning b. Compressor Inefficient, or Locked Sealed System Leak or Restriction	Check set-points. Adjust set-points COLDER 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 POWER key. Allow time for unit to pull down to temperature Allow time for unit to pull down to temperature Instruct Customer that unit performs best between 60°F - 90°F a. Adjust wine rack b. Adjust the door. c. Check hinges. Replace if defective. 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 power from fan motor to compressor. Reconnect or repair wires, or replace motor if defective. a. Check switch electrical connections. Check for power to / from switch. Reconnect or replace switch if defective. b. Check for power at J3 on control board. (NOTE: Unit must be running and not in Showroom Mode) If no power, replace board. Initiate Manual Valve Activation Mode, check for power at E2 on the control board. If no power, replace board. a. Check integrity of compressor electricals. Check continuity back to control board. Check for power at E2 on control board. Correct wiring problems or replace compressor electricals if defective. If no power at E2, replace control board. b. Check AMP draw on compressor. If high by 15% or more, replace compressor. SEE SEALED SYSTEM DIAGNOSTIC INFORMATION
C. WARM TEMPERATURE IN ONLY ONE WINE STORAGE COMPARTMENT	Control Set Too Warm Unit Recently Energized Unit Recently Stocked with Wine High Room Ambient Door Ajar a. Wine Rack Obstruction b. Door out of Adjustment c. Door or Cabinet Hinge Problem Thermistor Fault a. Evaporator Thermistor Location b. Evaporator Thermistor Wiring / Connections problem c. Evaporator or Compartment Thermistor Misread Condenser Air Flow / Fan Fault a. Dirty Condenser b. Fan Blade Loose, or Obstructed c. Fan Motor Disconnected or Malfunctioning Evaporator Fan / Fan Circuit Fault a. Fan Blade out of Position or Obstructed b. Fan Motor Disconnected or Malfunctioning Refrigerant Valve Fault a. Solenoid Disconnected, Mis-Wired, or defective b. Refrigerant Valve Stuck	Check/adjust set-points. Allow time for unit to pull down to temperature Allow time for unit to pull down to temperature Instruct Customer that unit performs best between 60°F - 90°F a. Adjust wine rack b. Adjust the door. c. Check hinges. Replace if defective. 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. Replace if defective. 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 power from fan motor to compressor. Reconnect or repair wires, or replace motor if defective. a. Check fan blade position. Reposition blade or move obstructions. b. Check fan motor electrical connections. Check power to motor. Repair connections, replace motor if defective. a. Initiate Manual Valve Activation Mode. 1. If valve inoperative: a. Check electrical connections. b. Check solenoid resistance for 295 ± 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	Wrong Units of Measure Selected, (Fahrenheit - °F vs. Celsius - °C) Compartment Thermistor Fault (Misread), or Control Board Fault	Initiate Temperature Units Selection Mode to check units of measure (°F or °C) selected. Check thermistor ohms = 30,000 - 33,000 at 32°F. Replace if defective. If thermistor is OK, replace control board.
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	Room Temperature Below Set-Point Control Set Too Cold Door Ajar a. Wine Rack Obstruction b. Door out of Adjustment c. Door or Cabinet Hinge Problem Compartment Thermistor Fault (Misread), or Control Board Fault	Instruct Customer. Check set-points. Adjust set-points WARMER a. Adjust wine rack b. Adjust the door. c. Check hinges. Replace if defective. Check thermistor ohms = 30,000 - 33,000 at 32°F. Replace if defective. If thermistor is OK, replace control board.
G. EXCESSIVELY COLD TEMPERATURES IN ONLY ONE WINE STORAGE COMPARTMENT	Room Temperature Below Set-Point Control Set Too Cold Door Ajar a. Wine Rack Obstruction b. Door out of Adjustment c. Door or Cabinet Hinge Problem Refrigerant Valve Stuck	Instruct Customer. Check set-point. Adjust set-points WARMER a. Adjust wine rack b. Adjust the door. c. Check hinges. Replace if defective. 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	Display Lighting Activated (ON 100%) Fan & Light Switch Wiring Crossed Door Switch Malfunction	Press & release LIGHTS key. Check wiring at fan & light switch, and at control board. Rewire if incorrect. Press & release LIGHTS key, then depress door switch. Repeat steps. If no effect, replace switch.
I. NO LIGHTS	Unit in Sabbath Mode Door Switch Disconnected or Malfunctioning Light Strips Burned-out No Power from Control Board	Press & release POWER key. Check switch electrical connections. Check for power to / from switch. Reconnect or replace switch if defective. If power from switch and relay, replace light strips. Check for power at E3 of control board. If no power, replace board.
J. CONTROL PANEL KEYS MALFUNCTIONING	Control Panel Ribbon Cable Plugged in Wrong Control Panel or Ribbon Cable Defective (OR) No Signal Read at Control Board	Check control panel ribbon cable at control panel (silver area of terminal away from control board). Plug in correctly if incorrect. SEE CONTROL PANEL TEST PROCEDURE AT BACK OF TROUBLESHOOTING GUIDE SECTION.
K. NO LED's	Unit Switched OFF LED Ribbon Cable Plugged in Wrong	Press POWER key Check LED ribbon cable. Plug in correctly if incorrect.
L. ALL LED's LIT	Bad Data from Control Board	Replace Control Board
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 WINDOWS	Bad LED Board in Control Panel	Replace Control Panel Assembly
O. DOOR / UNIT UN-LEVEL	Door or unit needs adjustment	SEE INSTALLATION MANUAL

SEALED SYSTEM DIAGNOSTIC INFORMATION

NOTES:

The temperature/pressure table below is for reference only. A unit's temperature/pressure correlation may differ from those listed due to: variations in evaporator thermistor location, set-points, where the sealed system is in the refrigeration cycle, ambient temperature, etc.
If a unit is experiencing temperature problems, it is recommended to reference the Error Code Troubleshooting Guide and General Troubleshooting Guide before accessing the sealed system. After all mechanical and electrical components have been ruled out, sealed system pressures can be checked and compared against those listed in the tables below.
Whenever entering the sealed system, always use solder-on process valves. Do NOT use bolt-on process valves as they are prone to leak.
Whenever servicing the sealed system, the refrigerant valve assembly (includes high-side filter-drier) must be replaced.

NORMAL OPERATING PRESSURES

Model	Normal Low Side Pressures	Normal High Side Pressures
UW-24	10 psig to 36 psig	90 psig to 100 psig

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

WINE STORAGE MEMBRANE SWITCH / RIBBON CABLE TEST PROCEDURE

The membrane switch is that part of the control panel assembly consisting of the function keys used for all input functions to the electronic control system. (See Figure 6-1)

Perform the eight continuity checks below if the integrity of the membrane switch and/or its ribbon cable is suspect. To perform these continuity checks, the ribbon cable must be disconnected from the control board.

NOTE: The wires of the ribbon cable are exposed at the back side of the terminal housing. With an Ohm Meter, check for continuity at these exposed points/pins. Pin #1 is at top of the terminal housing, closest to the arrow on the housing (see Figure 8-1).

Pressing no keys on the membrane switch; check for continuity across all pin combinations. With no keys pressed, there should be no continuity.
With POWER key pressed, there should be continuity across pins #4 & #6 only.
With lower wine storage COLDER key pressed, there should be continuity across pins #2 & #3 only.
With lower wine storage WARMER key pressed, there should be continuity across pins #3 & #4 only.
With upper wine storage COLDER key pressed, there should be continuity across pins #2 & #6 only.
With upper wine storage WARMER key pressed, there should be continuity across pins #6 & #7 only.
With LIGHTS key pressed, there should be continuity across pins #5 & #6 only.
With ALARM key pressed, there should be continuity across pins #3 & #7 only.

NOTE: If the membrane switch fails any of the above tests, the control panel assembly should be replaced. If all tests are passed and the control panel is still inoperable, replace the control board.

Figure 6-1. Control Panel / Membrane Switch

Control Panel Assembly

With exposed points/pins on back side of housing facing up, Pin #1 is marked

Models: UW-24, 424, UW-24 Under Counter Wine Storage Unit, UW-24, Under Counter Wine Storage Unit, Counter Wine Storage Unit, Wine Storage Unit, Storage Unit

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