Service Manual for the Lang Models:
EQS-AP, EQS-C
Lang Manufacturing Company 6500 Merrill Creek Parkway Everett, WA 98203
Phone: 1-800-224-5264 Fax: 1-425-349-2733
www.langworld.com
©Copyright 2000
TABLE OF CONTENTS
CHAPTER
1. TABLE OF CONTENTS..........................................................................................2
2. READ FIRST...........................................................................................................3
3. EQUIPMENT DESCRIPTION .................................................................................5
4. INSTALLATION ......................................................................................................6
5. START-UP..............................................................................................................7
6. CONTROL PANEL LAYOUT ..................................................................................8
7. PROGRAMMING TERMS ......................................................................................10
8. PROGRAMMING .................................................................................................... 11
9. GENERAL OPERATION......................................................................................... 13
10. TYPICAL OPERATION ..........................................................................................14
11. SEQUENCE OF OPERATION................................................................................ 15
PAGE
12. TROUBLESHOOTING............................................................................................16
13. TECHNICAL DATA ................................................................................................. 21
14. WIRING DIAGRAMS ..............................................................................................24
15. PARTS LIST ........................................................................................................... 26
2
IMPORTANT READ FIRST IMPORTANT
CAUTION
CAUTION
CAUTION
DANGER
WARNING
NOTICE
NOTICE
THE UNIT IS EXTREMELY HEAVY. FOR SAFE HANDLING, INSTALLER
SHOULD OBTAIN HELP AS NEEDED, OR EMPLOY APPROPRIATE
MATERIALS HANDLING EQUIPMENT (SUCH AS A FORKLIFT, DOLLY, OR
PALLET JACK) TO REMOVE THE UNIT FROM THE SKID AND MOVE IT TO
THE PLACE OF INSTALLATION.
ANY STAND, COUNTER OR OTHER DEVICE ON WHICH OVEN WILL BE
LOCATED MUST BE DESIGNED TO SUPPORT THE WEIGHT OF THE
OVEN.
SHIPPING STRAPS ARE UNDER TENSION AND CAN SNAP BACK WHEN
CUT.
THIS APPLIANCE MUST BE GROUNDED AT THE TERMINAL PROVIDED.
FAILURE TO GROUND THE APPLIANCE COULD RESULT IN
ELECTROCUTION AND DEATH.
INSTALLATION OF THE UNIT MUST BE DONE BY PERSONNEL
QUALIFIED TO WORK WITH ELECTRICITY AND PLUMBING. IMPROPER
INSTALLATION CAN CAUSE INJURY TO PERSONNEL AND/OR DAMAGE
TO EQUIPMENT. UNIT MUST BE INSTALLED IN ACCORDANCE WITH ALL
APPLICABLE CODES.
The data plate is on the back side of the oven above the power cord. The
oven voltage, wattage, serial number, wire size, and clearance
specifications are on the data plate. This information should be carefully
read and understood before proceeding with the installation.
The installation of any components such as a vent hood, grease
extractors, fire extinguisher systems, must conform to their applicable
National, State and locally recognized installation standards.
NOTICE
CAUTION
CAUTION
WARNING
CAUTION
NOTICE
During the first few hours of operation you may notice a small amount of
smoke coming from the oven, and a faint odor from the smoke. This is
normal for a new oven and will disappear after the first few hours of use.
ALWAYS KEEP THE AREA NEAR THE APPLIANCE FREE FROM
COMBUSTIBLE MATERIALS.
KEEP FLOOR IN FRONT OF EQUIPMENT CLEAN AND DRY. IF SPILLS
OCCUR, CLEAN IMMEDIATELY, TO AVOID THE DANGER OF SLIPS OR
FALLS.
KEEP WATER AND SOLUTIONS OUT OF CONTROLS. NEVER SPRAY OR
HOSE CONTROL CONSOLE, ELECTRICAL CONNECTIONS, ETC.
MOST CLEANERS ARE HARMFUL TO THE SKIN, EYES, MUCOUS
MEMBRANES AND CLOTHING. PRECAUTIONS SHOULD BE TAKEN TO
WEAR RUBBER GLOVES, GOGGLES OR FACE SHIELD AND
PROTECTIVE CLOTHING. CAREFULLY READ THE WARNING AND
FOLLOW THE DIRECTIONS ON THE LABEL OF THE CLEANER TO BE
USED.
Never leave a chlorine sanitizer in contact with stainless steel surfaces
longer than 10 minutes. Longer contact can cause corrosion.
3
IMPORTANT READ FIRST IMPORTANT
NOTICE
WARNING
NOTICE
CAUTION
Service on this, or any other, LANG appliance must be performed by
qualified personnel only. Consult your authorized service station directory
or call the factory at 1-800-224-LANG (5264), or WWW.LANGWORLD.COM
For the service station nearest you.
BOTH HIGH AND LOW VOLTAGES ARE PRESENT INSIDE THIS APPLIANCE
WHEN THE UNIT IS PLUGGED/WIRED INTO A LIVE RECEPTACLE. BEFORE
REPLACING ANY PARTS, DISCONNECT THE UNIT FROM THE ELECTRIC
POWER SUPPLY.
If an item on the list is followed by an asterisk (*), the work should be done
by a factory authorized service representative.
USE OF ANY REPLACEMENT PARTS OTHER THAN THOSE SUPPLIED BY
LANG OR THEIR AUTHORIZED DISTRIBUTORS CAN CAUSE BODILY
INJURY TO THE OPERATOR AND DAMAGE TO THE EQUIPMENT AND WILL
VOID ALL WARRANTIES.
4
EQUIPMENT DESCRIPTION
Lang Model: EQS
Electric Quarter Size Convention Oven
EXTERIOR
• The oven exterior dimensions are 19” (48.3 cm) Wide, 20.3” (51.5 cm) High, 27”
(68.6 cm) Deep. The Top, Front, Back, and Sides are constructed of stainless steel
with an aluminized bottom.
• The oven door comes standard with a window.
• The oven cavity is insulated with high temperature insulation for efficiency and
reduced heat loss.
INTERIOR
• The oven cavity dimensions are 15” (38.1 cm) Wide, 13” (33 cm) High, 14.5” (36.8
cm) Deep.
• The oven is designed for a maximum of three shelves and comes with three Chrome
Plated Racks.
• The interior of the oven is constructed of stainless steel.
OPERATION
• The EQS oven is a forced air convection oven with a vented oven cavity.
• The air is driven by a 1/6 HP fan motor.
CONTROLS
• The EQS is available either with the Lang Accu-Plus (EQS-AP), “Purple” Computer
(EHS-C) controls which include:
• EQS-AP
Easy to use manual control knobs.
Pulse and two speed fan.
Solid State temperature sensing and controls.
• EQS-C
Complete Computerized Controls with a Manual Override system.
Programmable up to 10 products with four “tiers” for each program.
Independent Shelf Timers for each Shelf.
Load Control through use of Cooking Curves.
Shelf Compensation Timing for uniform baking.
Single speed fan.
5
RECEIVING THE OVEN
Upon receipt, check for freight damage, both visible and concealed. Visible damage should
be noted on the freight bill at the time of delivery and signed by the carrier's agent.
Concealed loss or damage means loss or damage, which does not become apparent until the
merchandise has been unpacked.
If concealed loss or damage is discovered upon unpacking, make a written request for
inspection by the carrier's agent within 15 days of delivery. All packing material should be
kept for inspection.
Do not return damaged merchandise to Lang Manufacturing Company. File your claim
with the carrier.
Prior to un-crating, move the oven as near its intended location as practical. The crating
will help protect the unit from the physical damage normally associated with moving it
through hallways and doorways.
ELECTRICAL CONNECTION
The electrical connection must be made in accordance with local codes or in the absence of
local codes with NFPA No. 70 latest edition (in Canada use: CSA STD. C22.1)
The EQS is provided with a 48” cord and a NEMA #6-20 plug.
The EQS is not available in 480 Volt.
INSTALLATION
INSTALLING THE LEGS
Remove the legs from the oven cavity and screw them into the threaded holes provided on
the bottom of the oven.
A torpedo level placed on an oven rack will assist in leveling the oven.
Level the unit by unscrewing the adjuster on the bottom of each of the legs until the unit is
level.
PHASING
The EQS is provided with 208 or 240 VAC single phase only.
6
EQS-AP, EQS-C
Convection Oven Start-Up
1) Verify connections at plug and terminal block
2) Incoming Volt - Single Phase L1-L2______
Three Phase L1-L2______ L2-L3______ L3-L1______
3) Amp draw L1______
L2______
L3______
4) Motor amp draw ______
5) Are programs correct? Yes No
6) Verify actual temperature at 350 °F ________ °F.
Note:
Install thermocouple wire in center of oven cavity.
Let oven cycle off and on 3 times before recording temperature.
START-UPS
Set oven temperature for 350 °F
Model #_______ Date_______ Serial #________
Store #___________ Tech Name___________________
Contact_______________ Company _________________________
Store Phone #___________ Service Company Phone #______________
Address_____________________
______________________
______________________
7
CONTROL PANEL LAYOUT EQS-AP
8
CONTROL PANEL LAYOUT EQS-C
9
Control Panel Buttons
PROGRAMMING TERMS
1 -0
A - C
Man Prog
READ/CLEAR
Temp
Programming Terms
Cooking Curve
Product Buttons. These are the buttons where the product programs are stored.
Pressing a Product Button will heat the oven to the programmed temperature.
Shelf Buttons. The control is capable of timing each shelf individually. Pressing a
Product Button then a Shelf Button will start the countdown timer.
The MANUAL PROGRAM button allows the operator to enter a temporary
product program without being required to input the programming code. The
temporary program is erased when the oven is turned off or when a new program is
entered. Time and temperature are the only parameters that can be entered in the
Manual Program mode.
The READ/CLEAR button has several functions.
It is always the first button pressed when entering programming codes.
Pressing it twice then pressing a Product Button will "read-back" the program in
that product button.
Pressing and holding the button down until "88888" appears in the display will
cancel the current mode of the control and return the display to "Enter".
When the Temperature Recall Button is pressed, the display will indicate the
internal oven temperature. When released the display will revert to the previous
readout.
Cooking curve is a function of the computer that controls the cooking time. If the
temperature of the oven is lower than the programmed temperature, the control will
slow the timer down to compensate for the lower cooking temperature. Cooking
Curves from 0 - no time adjustment to 7 - maximum adjustment are available.
Cooking Curve 3 is the most commonly used. However, as a general rule the
longer the cooking time the lower the cooking curve, the shorter the cooking time
the higher the cooking curve.
FAN FUNCTION
TIER
The convection fan has two programmable options. Fan On (Fan 1) runs the
convection fan continuously. Fan Off (Fan 0) leaves the fan off until heat is called
for by the control. In a convection oven, the fan must
comes On. The convection fan can not
"Tiered" programming is the ability to change the cooking temperature or fan
function during the cooking cycle. As an example, some products require the fan
to be Off for the first half of the cooking cycle then turn On for the last half, Tier 1
would be programmed with the fan in the Off mode then Tier 2 would be fan On.
The Tier lamps located below the display (labeled T1, T2, T3, and T4) will
illuminate to indicate which Tier is being programmed or which Tier the program
is in during the cooking cycle.
be turned Off continuously.
10
come On whenever the heat
PROGRAMMING
ACTION DISPLAY
Turn the power switch on. If the oven is already on,
turn it off and then back on.
PROGRAMMING EQS-C
enter
Quickly enter access code “R/C 1 6 2 7 3 8”. Do
no hold the “R/C” button.
Select a Product number from 0-9.
Select amount of time that product should steam. If
no steam is required press the shelf “A” button to
advance to the next step.
Note: If oven is not strapped for steam convection
then this step will not be provided.
Select a Temperature from 150°F-450°F.
NOTE: Entering “000” will erase the existing
program.
Select the desired cooking curve from 0-7.
Enter a desired Fan setting.
“0” (nofan) Will make the fan pulse with the heat.
“1” (fanonhi) Will make the fan run on high
continuously.
“2” (fanonlo) Will make the fan run on low
continuously.
Enter the desired cooking time
(hours:minutes:seconds)
prod
St: 00
000°F
CC0-7
Fano12
00: 00: 00
000°f
The program is now entered for a single tier
program, press the “E” button (located behind the
“A” and “G” on the LANG logo) to continue
programming other products. If the program is a
multi tiered program continue by programming the
next tiers. When complete press the “E” button.
When the programs have been completely entered
press the “R/C” button to save and exit the
programming cycle.
prod
enter
11
PROGRAMMING EQS-C CONT’D
EQS-C PROGRAMMING CODES
Below are codes, which will allow you to configure the display or aid in the operation, and
troubleshooting of the oven.
The readout must display "ENTER" before the computer will accept any programming code. If the
readout displays any other word, reset the computer by pressing and holding the “R/C” button until
display reads “88888” then release. Display should now read “ENTER”.
The control allows for a 3-second delay between each button push, if a delay of longer than 3 seconds
has occurred, the programming code must be re-entered.
The instructions call for pressing exactly what is shown under "PRESS".
CODE DESCRIPTION PRESS
• OPERATIONAL
Recall time remaining on a shelf Shelf
Cancel a shelf timer R/C, R/C, Shelf
• DISPLAY MODES
Countdown timer display R/C,4,8,4,8,4,8
Shelf in use display R/C,0,9,0,9,0,9
Internal oven temperature display R/C,8,7,8,7,8,7
• PROGRAMMING
Enter programming mode R/C,1,6,2,7,3,8
Recall an existing product program R/C, R/C, P (Product programmed)
Erase a product program R/C,1,6,2,7,3,8 (P) (000)
Model identification R/C, D,C,D,C,D,C
Fan Setting ( HI or Both) R/C,E,D,C,B,A,1(high),2 (both)
Program download (Contact Factory) R/C, A, B, C, D, E, P
• MAINTENANCE
Actual oven temperature
Return to ENTER
R/C,3,4,5,6,7,8
R/C
• SHELF COMPENSATION
Enter shelf compensation mode R/C, C, B, C, B, C, B
Set shelf compensations (I.E.) A,2,3,A
Return to ENTER R/C
12
GENERAL
OPERATIONS
Convection ovens constantly circulate air over the product. This strips away the thin layer of moisture and cool
air from the top of the product. Heat penetrates more quickly. Cooking times are shortened and cooking
temperatures are usually reduced.
To convert standard deck oven recipes to convection oven recipes, reduce the temperature 50 °F and the time by
25%. Make adjustments as necessary, depending upon your results.
The lower the temperature the more even the bake.
Check the product halfway through the baking cycle. Look through the door windows. Opening the oven door is
not recommended.
If products are brown on the outside and not done on the inside, too high a temperature is being used. Decrease
the temperature 15-25 °F.
If products are pulling to the edge of pans or spilling, the oven is not leveled or the pans are warped. Correct as
necessary.
Load each shelf evenly. Spaces should be maintained equally between the pan and walls. Front and back. This
will allow an even distribution of airflow.
BAKING
Most baking should be done with the vent closed. Open the vent only with high moisture products to avoid
seepage around the front of the door.
Always weigh your product. This will give you a more consistent size, color and quality.
Center the pan in the oven. The better the air flow around the product, the better the bake.
The convection oven is a mechanical piece of equipment. The same control settings will always give the same
results. If the results vary, problems may be because of preparation, not the oven.
LOADING
Place product as close to oven as practical. Open oven doors and load quickly but carefully.
If only one pan is required, load on center shelf. If two pans are required, load on the top and bottom shelf. If
three pans are required, load on top shelf, bottom shelf, and center shelf.
UNLOADING
It is a characteristic of all convection ovens to unload the top shelf before the bottom shelves. The rising of heat
and the hot oven ceiling causes the top shelf to bake quicker. This characteristic is more pronounced when
baking at higher temperatures and/or for prolonged periods of time.
13
TYPICAL OPERATION
EQS-AP TYPICAL OPERATION SEQUENCE
ACTION RESULT
Turn power switch to ON. Control panel heat call light comes on.
Adjust proper temperature, between 140 & 450
degrees and allow to preheat up to 20 minutes.
Open oven doors and insert product, set timer up to
60 minutes.
Timer beeps continuously when done. Product should now be done.
Oven begins heating.
Timer begins counting down.
EQS-C TYPICAL OPERATION SEQUENCE
ACTION RESULT
Turn power switch to ON. Control panel comes on, display says “88888” and
then “ENTER”, motor starts.
Press a product button. Display says “PREHT” (Preheat), oven begins to heat
to the programmed temperature.
Beeper sounds briefly. Display says “READY”.
Open the oven doors and load the product. Close the
door and press the product button again.
Press the shelf button(s) which correspond to the
shelf positions which the product is loaded (A
equals the top shelf and E equals the bottom shelf).
Beeper sounds continuously. Display shows “DONE”, shelf button(s) flash.
Beeper sounds briefly and display says “SHELF”.
Display shows a countdown timer and begins to
count toward zero.
Press the flashing shelf button(s). Beeper stops. Display shows “READY” if no other
shelves carry product or resume count down for
shelves that still have product cooking.
Open oven door and remove the product, which
corresponds to flashing shelf button(s).
14
EQS-AP
Power switch turned on.
208/240 VAC across Common terminals on power switch.
208/240 VAC to Common terminals of Motor relay.
208/240 VAC to Common terminals of Heat relay.
240/24-volt transformer energized.
24 VAC across “C” and “D” (common) of 24 pin Terminal block.
24 VAC across coil of Motor relay. (Through door switch)
24 VAC across “D” and of Heat contactor. (Through door switch and high limit thermostat)
24 VAC across “D” and Heat output on board.
Motor contactor closes.
Motor starts.
24 VAC across coil of Heat contactor.
Heat contactor closes.
208/240 volts to elements.
Oven heats.
SEQUENCE OF OPERATION
EQS-C
Power switch turned on.
240/208 VAC across Common terminals on power switch.
240/208 VAC across both transformers (240/24, 240/12).
240/208 VAC to Common terminals of Motor relay.
240/208 VAC across common terminals of Heat relay.
240/24 volt transformer energized.
240/12 volt transformer energized.
24 VAC across ground and TP4, TP5 and TP6.
12 volts to TP1 on microprocessor.
24 VAC across coil of motor contactor.
Motor contactor closes.
240/208 VAC across NO (Normally open) contacts of Motor relay.
Motor starts.
24 VAC across coil of Heat contactor.
Heat contactor closes.
208/240 volts to elements.
Oven heats.
15
NO MOTOR
PROBABLE CAUSE CORRECTIVE ACTION
TROUBLESHOOTING EQS-AP
Defective Fan Switch
Defective Transformer
Defective Motor Relay
Defective Door Switch
Defective Motor
NO HEAT
PROBABLE CAUSE CORRECTIVE ACTION
Defective Elements
Defective Transformer
Defective Probe
Defective Heat Contactor
Defective Circuit board
Verify that Fan switch is in “ON” position (In pulse position motor
will only cycle when oven calls for heat).
Check transformer for normal operation.
Check motor relay for normal operation. (24VAC 35 Ω)
Check door switch for normal operation.
Check motor for normal operation. (P1-T9 low, P1-T7/T4 high)
Check that elements are getting power.
Confirm that Elements are working correctly. (See Technical Data)
Check transformer for normal operation.
Replace if necessary.
Confirm that probe has proper resistance for the correct temp. (See
Technical Data)
Confirm that Contactor is getting correct voltage.
Confirm that Contactor is operating properly. (24VAC 6Ω)
Confirm that Heat Call light is on.
If no light is detected:
Check 12-position switch for normal operation. (See Technical Data)
If light is detected:
Check for 24VAC across heat output and “D” on 12 Pole terminal.
If voltage is not present:
Replace Circuit board.
If voltage is present:
Check over temperature thermostat for proper operation.
Check door switch for normal operation.
16
TROUBLESHOOTING EQS-C
To help troubleshoot the oven you should perform the following “Manual Override” test:
Open drop down door located on the lower right side, directly below front panel.
Turn back up toggle (on/off) switch to “on” position.
Turn main power switch to “on” position.
Check oven for normal operation.
NO DISPLAY
PROBABLE CAUSE CORRECTIVE ACTION
Power switch is not turned on Turn power switch on.
Defective power switch Check power switch for normal operation. Replace as necessary.
Defective back-up relay Check relay for normal operation.
Check coil for 24 VAC.
If 24 VAC is measured. Turn oven off and:
Check coil for 7.2 KΩ.
Replace as necessary.
If 24 VAC is not measured.
Verify that manual override switch is in “off” position.
Check manual override switch for normal operation.
Check wires for any shorts.
Defective control transformer
(12 VAC).
Defective rectifier Check for no less than 10.5 VAC on TP1 and 5 VDC on TP2.
Check transformer for normal operation.
Check primary coil for 208/240 VAC and 630 Ω. Check secondary
coil for no less than 10.5 VAC and 1 Ω.
If voltage is measured on primary:
Check for voltage on secondary.
Replace transformer.
If voltage is not measured on primary:
Check wires for any shorts.
If correct voltage is present at TP1 and present, but low at TP2
unplug both ribbon connections from CPU and re-measure at TP2.
If voltage remains low at TP2 replace CPU (40102-311).
If voltage at TP2 increased to 5 VDC when ribbon was unplugged,
plug ribbon back in to CPU and disconnect from Interface board.
Re-measure at TP2.
If voltage dropped to below 5 VDC replace ribbon cable (31110-01).
If voltage remains at 5 VDC, plug ribbon back into Interface board
and measure for 5 VDC at TP3.
If voltage is present at TP3 and display is still not on, press and hold
the R/C button on board if LED’s come on replace Interface board.
If LED segment does not illuminate or the LED is blank, replace
LED.
At this point you should have a display.
17
NO FAN-Manual Mode
PROBABLE CAUSE CORRECTIVE ACTION
TROUBLESHOOTING EQS-C CONT’D
Defective 240/24 VAC
transformer
Back-up relay not energizing Check for 240 VAC on relay coil.
Motor contactor not energized Check for 24 VAC at contactor or relay coil.
Check for 24 VAC on “C” and “D” of the terminal block.
If 24 VAC is not measured: Turn off and:
Check secondary coil for 1 Ω.
Check primary coil for 77 Ω.
Replace transformer.
If 24 VAC is measured: Turn off and:
Check back-up relay for normal operation.
If 240 VAC is measured: Turn unit off and:
Check back-up relay coil for 7.2 K Ω.
Replace if defective.
If 240 VAC is not measured:
Check back-up switch (SPDT) for normal operation.
Replace if defective.
If 24 VAC is not measured: Turn oven off and:
Check door switch for normal operation.
Check door switch for continuity.
Replace or adjust door switch.
If 24 VAC is measured: Turn unit off and:
Check contactor coil for continuity.
Replace if defective.
No voltage across contactor
points
Check 208/240 VAC across “C” terminals of contactor.
If 208/240 VAC is not measured:
Check connection to main contactor (heat contactor).
Check circuit breaker.
If 208/240 VAC is measured:
Check across “NO” contacts. Should have 208/240 VAC.
Replace if defective.
NO MOTOR COMPUTER MODE
PROBABLE CAUSE CORRECTIVE ACTION
No 24 VAC on Interface board Check for 24 VAC at TP4 to common (“D”).
If 24 VAC is not measured:
Check for 24 VAC at “NC” contacts on back-up relay.
If 24 VAC is measured:
Check for 24 VAC at TP5.
Replace Interface board if defective.
18
TROUBLESHOOTING EQS-C CONT’D
NO HEAT Manual Mode
NOTE: Fan must be operating before trouble shooting No heat.
PROBABLE CAUSE CORRECTIVE ACTION
Back-up relay not energizing Check for 240 VAC on relay coil.
If 240 VAC is measured. Turn unit off and:
Check back-up relay coil for 7.2 Ω.
Check “NO” contacts for 24 VAC.
Replace if defective.
If 240 VAC is not measured:
Check back-up switch (SPDT) for normal operation.
Replace if defective.
Defective thermostat Turn unit off and check for continuity while cycling thermostat on
and off.
Replace if defective.
Defective contactor Check for 24 VAC at heater coil.
If 24 VAC is measured. Turn oven off and:
Check for continuity through coil.
Replace if defective.
Defective elements Check elements for continuity.
Defective over-temp thermostat Check for 24 VAC on #55 red wire to common “D”.
NO HEAT Computer Mode
PROBABLE CAUSE CORRECTIVE ACTION
No 24 VAC on Interface board Check for 24 VAC at TP4 to ground.
If 24 VAC is not measured. Turn oven off and:
Check for continuity through hi-temp wires going to over-temp
thermostat.
Replace over-temp thermostat if defective.
Replace if defective.
If 24 VAC is not measured: Turn oven off and:
Check for continuity through over-temp thermostat.
Replace if defective.
If 24 VAC is not measured:
Check for 24 VAC at “NC” contacts on back-up relay.
If 24 VAC is measured:
Check for 24 VAC at TP6.
Replace Interface board if defective.
19
DISPLAY LOCKS UP
PROBABLE CAUSE CORRECTIVE ACTION
“Help” in display Check probe for proper resistance.
“88888” stuck in display Check for stuck button by pressing any button.
TROUBLESHOOTING EQS-C CONT’D
Check that probe connections are secure.
Push “TEMP” button on control board and check to see if temperature
rapidly descends. If temp does descend rapidly, replace ribbon cable.
Check to see that contactors/relays are not stuck in the closed
position.
Replace contactor if defective.
Check for foreign objects keeping contactor closed.
If computer beeps or chirps:
Check control panel transformer (12 VAC) for proper operation.
Check TP1 for at least 10.5 VAC.
Check TP2 for at least 4.99 VDC.
Check TP3 for at least 4.97 VDC.
If computer does not beep or chirp:
Check each button for movement.
Check that panel label has not been damaged in any way.
Replace button if defective.
Replace panel label.
Display has shelf “A” Read Programming Codes.
20
ELEMENT RESISTANCE
TECHNICAL DATA
208 Volt 11090-32
240 Volt 11090-33
16 Ω
21 Ω
13 Amps
11 Amps
TRANSFORMER RESISTANCE
TRANSFORMER Input Primary Secondary Output
208/24 Volt 208/240 Volt
240/12 Volt 208/240 Volt
208/240-24/12 208/240 Volt 208V
77 Ω 1Ω
630 Ω 1 Ω
64 Ω
240V
75Ω
12V
.6Ω
24V
1Ω
24 Volt
12 Volt
24/12 Volts
CONTACTOR RESISTANCE
CONTACTOR Coil
2 Pole 24 Volt coil (P & B) (PP & PT motor)
35 Ω
OVER-TEMP THERMOSTAT
OVER-TEMP
Wires #4 and #19 Normally closed
DOOR SWITCH
Check switch between “COM” (common) and “NO” (normally open) contacts, insure switch closes approximately 3 to 4
inches before door closes.
BLOWER FAN
Blower fan will rotate clockwise and should have a 5/8“ gap between it and the back wall of the can.
21
TECHNICAL DATA CONT’D
PROBE RESISTANCE
TEMP RESISTANCE VOLT DROP TEMP RESISTANCE VOLT DROP
70 556 1.11 290 881 1.76
80 569 1.14 300 897 1.79
90 583 1.17 310 914 1.83
100 596 1.19 320 931 1.86
110 610 1.22 330 948 1.90
120 623 1.25 340 965 1.93
130 637 1.27 350 983 1.97
140 651 1.3 360 1000 2.00
150 665 1.33 370 1018 2.04
160 678 1.36 380 1036 2.07
170 694 1.39 390 1054 2.11
180 709 1.42 400 1072 2.14
190 724 1.45 410 1090 2.18
200 739 1.48 420 1109 2.22
210 754 1.51 430 1127 2.25
220 769 1.54 440 1146 2.29
230 785 1.57 450 1165 2.33
240 800 1.60 460 1184 2.37
250 816 1.63 470 1204 2.41
260 832 1.66 480 1223 2.45
270 848 1.70 490 1243 2.49
280 864 1.73 500 1263 2.53
NOTE
Probe is factory checked at 350 °F. Must be completely disconnected from circuit board when measuring
probe resistance. Display will read “HELP” if probe is open or unplugged. Any probe resistance can be
multiplied by 2 milli-amps (.002) to determine voltage drop.
22
EHS-C TEST POINT LAYOUT
TECHNICAL DATA CONT’D
TP 1
TP5
TP7
23
EQS-AP 208/240 WIRING DIAGRAM
24
EQS-C 208/240 WIRING DIAGRAM
25
PARTS LIST EQS-AP
DESCRIPTION PART NO.
Element EQS Oven 208 Volt 2700 Watts 11090-32
Power Cord 31106-04
Power Cord Plug 31203-19
Oven Pan 25-420
Motor 1/6 HP 208/240 Volt 30200-41
Switch, Micro Oven Door 30301-02
Switch Toggle On-Off 30303-06
Switch, Temperature Control 30304-16
Safety Thermostat 490°F Open
Terminal Block 30501-02
Contactor 2 Pole 24 VAC, Heat 30701-04
Contactor 2 Pole 24 VAC, Motor 30701-05
Timer, Electric 30800-05
Buzzer, Electric Timer 30802-04
Transformer 240/24 VAC 31400-10
Pilot Light 31601-07
Circuit Board, Temperature Control 40101-19
Oven Temperature Sensor 41100-12
Oven Rack 50200-74
Door Handle 70603-25
Spring, EQS Door 51001-21
Panel Label 60301-126
Knob, Time/Temperature Control 70701-28
Window, Oven Door 71301-04
Fan, Convection Blower 71500-09
Fan, Convection Cooling 71500-10
Leg, 4” Stainless Steel 72500-02
60102-1021
26
PARTS LIST EQS-C
DESCRIPTION PART NO.
Element EQS Oven 208 Volt 2700 Watts 11090-32
Power Cord 31106-04
Power Cord Plug 31203-19
Oven Pan 25-420
Oven Top 25-271
Oven Sides, Left or Right 25-273
Oven Back 25-276
Microswitch Rod 25-301
Spring Spacer 25-304
Washer 5/16” SAE 20201-09
Motor 1/6 HP 208/240 Volt 30200-41
Switch, Micro Oven Door 30301-02
Switch Toggle On-Off 30303-06
Safety Thermostat 490°F Open
Terminal Block 30501-02
Contactor 2 Pole 24 VAC, Heat 30701-04
Contactor 2 Pole 24 VAC, Motor 30701-05
Ribbon Cable 31110-01
Transformer 240/24 VAC 31400-10
Transformer 240/12 VAC 31400-26
Circuit Board, Buzzer 40102-10
Circuit Board, Front Panel 40102-23
Circuit Board, Microprocessor 40102-44
Oven Temperature Sensor 41100-12
Oven Rack 50200-74
Door Handle 70603-25
Spring, EQS Door 51001-21
Panel Label 60301-115
Window, Oven Door 71301-04
Fan, Convection Blower 71500-09
Fan, Convection Cooling 71500-10
Leg, 4” Stainless Steel 72500-02
60102-1021
27
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