PS520-Series Gas Ovens: English
A MIDDLEBY COMPANY
owner's
operating
& installation
manual
PS520-Series OVENS
Model PS520G
PS520 (Single)
PS520 (Triple)
PS520 (Double)
Part No. 59223 Rev. C
Price $30.00
©2012 Middleby Marshall Inc.
P: 04/12
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Model No.
Modéle No.
Serial No.
Serié No.
Installation Date
Date d'installation
MIDDLEBY MARSHALL
No Quibble limited WarraNty
(U.S.A. Only)
MIDDLEBY MARSHALL INC.
OVEN LIMITED WARRANTY
(Non U.S.A.)
The Seller warrants equipment manufactured by it to be free from
defects in material and workmanship for which it is responsible. The
Seller’sobligationunderthiswarrantyshallbelimitedtoreplacingor
repairing, at Seller’s option, without charge, F.O.B. Seller’s factory,
any part found to be defective and any labor and material expense
incurred by Seller in repairing or replacing such part. Such warranty
is limited to a period of one year from date of original installation or
15 months from date of shipment from Seller’s factory, whichever
is earlier, provided that terms of payment have been fully met. All
labor shall be performed during regular working hours. Overtime
premium will be charged to the Buyer.
MIDDLEBY MARSHALL, HEREINAFTER REFERRED TO
AS “THE SELLER”, WARRANTS EQUIPMENT MANUFAC-
TURED BY IT TO BE FREE FROM DEFECTS IN MATERIAL
AND WORKMANSHIP FOR WHICH IT IS RESPONSIBLE.
THE SELLER’S OBLIGATION UNDER THIS WARRANTY
SHALL BE LIMITED TO REPLACING OR REPAIRING,
AT SELLER’S OPTION, WITHOUT CHARGE, ANY PART
FOUND TO BE DEFECTIVE AND ANY LABOR AND MATE-
RIAL EXPENSE INCURRED BY SELLER IN REPAIRING
OR REPLACING SUCH PART. SUCH WARRANTY SHALL
BE LIMITED TO THE ORIGINAL PURCHASER ONLY
AND SHALL BE EFFECTIVE FOR A PERIOD OF ONE
YEAR FROM DATE OF ORIGINAL INSTALLATION, OR 18
MONTHS FROM DATE OF PURCHASE, WHICHEVER IS
EARLIER, PROVIDED THAT TERMS OF PAYMENT HAVE
BEEN FULLY MET.
This warranty is not valid unless equipment is installed,
started, and demonstrated under the supervision of a factory-
authorized installer.
Normal maintenance functions, including lubrication, adjustment of
airflow,thermostats,doormechanisms,microswitches,burnersand
pilot burners, and replacement of light bulbs, fuses and indicating
lights, are not covered by warranty.
This warranty is valid only if the equipment is installed,
started, and demonstrated under the supervision of a factory-
authorized installer.
Anyrepairsorreplacementsofdefectivepartsshallbeperformedby
Seller’sauthorizedservicepersonnel.Sellershallnotberesponsible
for any costs incurred if the work is performed by other than Seller’s
authorized service personnel.
Normal maintenance functions, including lubrication, clean-
ing, or customer abuse, are not covered by this no quibble
warranty.
When returning any part under warranty, the part must be intact
and complete, without evidence of misuse or abuse, freight prepaid.
Seller shall be responsible only for repairs or replacements of
defective parts performed by Seller’s authorized service per-
sonnel. Authorized service agencies are located in principal
cities throughout the contiguous United States, Alaska, and
Hawaii. This warranty is valid in the 50 United States and
is void elsewhere unless the product is purchased through
Middleby International with warranty included.
Seller shall not be liable for consequential damages of any kind
which occur during the course of installation of equipment, or which
result from the use or misuse by Buyer, its employees or others of
the equipment supplied hereunder, and Buyer’s sole and exclusive
remedy against Seller for any breach of the foregoing warranty or
otherwise shall be for the repair or replacement of the equipment
or parts thereof affected by such breach.
The foregoing warranty is exclusive and in lieu of all
other warranties, expressed or implied. There are no
implied warranties of merchantability or of fitness for a
particular purpose.
The foregoing warranty shall be valid and binding upon Seller if and
only if Buyer loads, operates and maintains the equipment supplied
hereunder in accordance with the instruction manual provided to
Buyer. Seller does not guarantee the process of manufacture by
Buyer or the quality of product to be produced by the equipment
supplied hereunder and Seller shall not be liable for any prospective
or lost profits of Buyer.
The foregoing shall be Seller’s sole and exclusive obliga-
tion and Buyer’s sole and exclusive remedy for any action,
including breach of contract or negligence. In no event shall
Seller be liable for a sum in excess of the purchase price of
the item. Seller shall not be liable for any prospective or lost
profits of Buyer.
THE FOREGOING WARRANTY IS EXCLUSIVE AND IN LIEU OF
ALL OTHER EXPRESS AND IMPLIED WARRANTIES WHATSO-
EVER. SPECIFICALLY THERE ARE NO IMPLIED WARRANTIES
OF MERCHANTABILITY OR OF FITNESS FOR A PARTICULAR
PURPOSE.
This warranty is effective on Middleby Marshall equip-
ment sold on, or after, February 15, 1995.
The foregoing shall be Seller’s sole and exclusive obligation and
Buyer’ssoleandexclusiveremedyforanyaction, whetherinbreach
of contract or negligence. In no event shall seller be liable for a sum
in excess of the purchase price of the item.
© 2003 - Middleby Marshall, A Middleby Company.
The Middleby Marshall logo is a registered trademark of Middleby Marshall, A Middleby Company.
Middleby Marshall Inc. • 1400 Toastmaster Drive • Elgin, Illinois 60120-9272 U.S.A. • (847) 741-3300 • FAX: (847) 741 4406
iii
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TABLE OF CONTENTS
TABLE OF CONTENTS
(Continued)
Page
SECTION 1
Page
I. MODEL IDENTIFICATION ..............................................1
SERIES PS520 GAS SPECIFICATIONS.............................2
II. COMPONENT FUNCTION .............................................4
A. Conveyor Motor and Conveyor Belt ........................4
B. Blower Fan .................................................................4
C. Gas Burner .................................................................4
D. Cooling Fan ................................................................4
E. Air Fingers and Blank Plates - See Figure 1-9 ........4
SECTION 2
III. STEP-BY-STEP OPERATION ........................................22
A. Startup Procedures ..................................................22
Daily Startup..................................................................22
Power Failure.................................................................22
B. Shutdown Procedure ..............................................22
IV. NORMAL OPERATION - STEP-BY-STEP................... 24
A.Daily Startup Procedure............................................ 24
B. Daily Shutdown Procedure ..................................... 24
V. QUICK REFERENCE: TROUBLESHOOTING............ 26
SECTION 4 MAINTENANCE
I. UNLOADING ....................................................................8
PARTS LIST FOR SERIES PS520 GAS OVEN
I. MAINTENANCE - DAILY............................................. 28
A. Exterior...................................................................... 28
B. Cooling Fan............................................................... 28
C. Conveyor Belt ........................................................ 28
D. Crumb Pans ............................................................ 28
II. MAINTENANCE - MONTHLY ...................................... 29
A. Removing Conveyor From Oven For Cleaning .... 29
B. Air Fingers Disassembly For Cleaning.................. 31
C. Reassembly of Air Fingers ..................................... 32
D. Reinstall End Plugs ................................................. 35
E. Conveyor Reassembly Into Oven........................... 36
F. Checking Conveyor Belt Tension........................... 36
G. Conveyor Belt Link Removal.................................. 37
H. Attaching Drive Chain ............................................. 38
III. MAINTENANCE - EVERY 3 MONTHS ......................... 39
A. Electrical Terminals................................................. 39
B. Ventilation ................................................................ 39
IV. MAINTENANCE - EVERY 6 MONTHS......................... 39
PS520-SERIES GAS OVEN KEY SPARE
INSTALLATION KIT .....................................................8
UTILITY ROUGH-IN DIMENSIONS AND POSITIONING
FOR PS520-SERIES OVENS .....................................13
CIRCUIT BREAKER.......................................................13
ELECTRICAL SPECIFICATIONS ..................................13
ELECTRICAL RATING...................................................13
SUPPLY WIRE ...............................................................13
SUGGESTED..................................................................13
II. VENTILATION GUIDELINES.........................................13
III. ELECTRICAL CONNECTION INFORMATION FOR
PS520-SERIES OVENS..............................................14
IV. ELECTRIC SUPPLY FOR GAS HEATED OVENS ......14
V. GAS SUPPLY ...............................................................15
SECTION 3 INSTALLATION
I. CONTROL FUNCTIONS.................................................19
II. COMPONENT INFORMATION AND LOCATION ........20
A. Door Safety Switch ..................................................20
B. Blower Switch ..........................................................20
C. Heat Switch ..............................................................20
D. Temperature Controller............................................20
E. Conveyor .................................................................21
MEASURING CONVEYOR SPEED. ..............................21
PARTS ...................................................................... 40
KEY SPARE PARTS KIT ............................................... 40
SECTION 5 TROUBLESHOOTING
Troubleshooting Charts...................................................... 41
SECTION 6 ELECTRICAL SCHEMATICS
Wiring Diagram, G208-240V 50/60 GO, PS520 ............... 43
NOTE
Wiring Diagrams are in Section 6 of this Manual.
The diagram for each oven is also on the lower
inner surface of its Control Console.
iv
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SECTION 1
DESCRIPTION
SECTION 1
DESCRIPTION
I. MODEL IDENTIFICATION
The Middleby Marshall PS520-Series may be used
either as a single oven or stacked for use as double or
triple ovens.
AsinglePS520-SeriesOven(Figure1-1)ismountedona
base pad with legs. A double oven (Figure 1-2) consists
of two, stacked, single ovens. A triple oven (Figure 1-3)
consists of three stacked single ovens. The lower oven
is mounted on a base pad with stacking pins.
On a double or triple oven, the ovens operate indepen-
dently. All ovens use identical controls and components.
One oven can be cleaned or serviced, while the others
are operating.
Figure 1-1. Single PS520 Oven
Figure 1-2. Double PS520 Oven
Figure 1-3. Triple PS520 Oven
1
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SECTION 1
DESCRIPTION
PS520 SERIES OVEN SPECIFICATIONS
Conveyor Belt Width
Heating Zone Length
Baking Area Square Feet
18.00″ (457mm)
20.00″ (5098mm)
2.5 sq. ft. (0.23 sq. m.)
Overall Dimension – Standard Single Oven w/Legs
42.00″ (1067mm) L ×
35.21″ (894mm) W ×
21.10″ (536mm) H ×
Overall Dimension – Double Oven
42.00″ (1067mm) L ×
35.21″ (894mm) W ×
36.64″ (931mm) H x
Overall Dimension – Triple Oven
42.00″ (1067mm) L x
35.21″ (894mm) W ×
48.19″ (1224mm) H ×
Weight of Single Oven
Shipping Weight
250 lb (93.3kg)
325 lb (121.3kg)
22.1 ft3 (0.62 m3)
8.3 kW/hr
Shipping Cube
Operating Range
BTU's – Natural or Propane Gas
Gas Input – Natural or Propane Gas
Maximum Operating Temperature
Warm-up Time
40,000 BTU/HR (42 MJ/hr)
1/2″ NPT (1/2" BS)
600°F (316°C)
20 min.
Belt Speed Limits
1-10 minutes
SERIES PS520 ELECTRICAL SPECIFICATIONS
Main Blower &
Elements Voltage
Control Circuit
Voltage
Phase
Frequency
Amperage
Draw
Poles
Wires
208-240V
208-240V
1 Ph
50/60 Hz
1.5 Amp
2 Pole
3 Wire
(2 hot, 1 grd)
GAS ORIFICE AND PRESSURE SPECIFICATIONS (PER OVEN CAVITY) - DOMESTIC AND STANDARD EX-
PORT OVENS
Orifice (Manifold)
Gas Type
Natural
Main Orifice I.D.
Supply (Inlet) Pressure
Pressure
0.082” (2.08mm, #45 drill)
0.057” (1.45mm, #46 drill)
6-12” W.C. (14.9-29.9mbar) (1.49-3 KPA) * 3.5” W.C. (8.72mbar) (0.872 KPA)
11-14” W.C. (27.4-34.9mbar) (2.74-3.5 KPA)* 7” W.C. (17.44mbar) (1.75 KPA)
Propane
* The gas supply pressures and orifice sizes shown are for ovens installed in North America. The required gas supply pressures and orifice sizes
of ovens installed in other locations are dependent on the local gas type and on all applicable local codes.
GAS ORIFICE AND PRESSURE SPECIFICATIONS (PER OVEN CAVITY) - CE OVENS
Supply (Inlet) Pressure
IT,PT,ES,SE,
Main
Orifice
dia.
UK,CH,IT,AT,
DK,FI
I2H
SE,CH,AT,DK, BE,IE,IT,PT,
Orifice
(Manifold)
Pressure
Rated
Heat
Input
Gas
Type
DE
I2E
BE,FR
I2E+
FI,DE,NL
I3B/P
ES,UK
I3+
G20
G25
G30
2.3749
mm
20
mbar
20
mbar
20
mbar
--
--
--
--
11.21
mbar
22.36
kW-hr.
2.3749
mm
--
--
--
16.19
mbar
22.36
kW-hr.
1.3970
mm
--
--
--
29 or 50
mbar
28-30, 37
or 50 mbar
26.2
mbar
22.59
kW-hr.
NOTE
Wiring Diagrams are contained in Section 6 of this Manual
and are also located inside the oven at the
bottom of the Control Panel.
Additional electrical information is provided on the oven's serial plate.
This Manual Must Be Kept For Future Reference.
2
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SECTION 1
DESCRIPTION
II. COMPONENT FUNCTION (Figure 1-4)
Figure 1-4. PS520-Series Oven Components Locations
3
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SECTION 1
DESCRIPTION
II. COMPONENT FUNCTION
A. Conveyor Motor and Conveyor Belt
The conveyor belt is driven by a variable-speed electric
motor (Figure 1-5) operating through a gear reducer.
The motor speed is controlled by a digital control. The
stainless-steel wire belt can travel in either direction at
variableratesrangingfrom3minutesto30minutes;thisis
thetimethataproductcantaketopassthroughtheoven.
B. Blower Fan
The blower fans are located at the rear of the oven.
These blowers force heated air through the air fingers.
The BLOWER switch must be set to “ON” or “I” for oven
warmup and baking.
C. Gas Burner
The gas burner is located inside the rear panel and is
controlled by the temperature controller.
D. Cooling Fan — See Figure 1-5 and Figure 1-6
Blower Assembly
The cooling fan is located in the back of the oven.
The cooling fan draws air through its grille, blowing it
through the blower motor compartment and the control
compartments into the oven top and exhausted out the
front louvers.
E. Air Fingers and Blank Plates - See Figure 1-7
E1. Air Fingers
An Air Finger Assembly is made up of three parts:
1. Outer Plate - The Outer Plate is the removable cover-
ing with tapered holes, which direct the air stream onto
the product being baked.
2. Inner Plate -The perforated Inner Plate is vital in
forming the unique air jets. It must be assembled into
the manifold with its holes aligned with the holes of the
outer plate.
3. Manifold - The Manifold is the assembly which slides
on tracks into the oven plenum.
Right Control Box
Figure 1-5. Machinery Compartment
Components
4
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SECTION 1
DESCRIPTION
Figure 1-6. Cooling Fan
5
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SECTION 1
DESCRIPTION
F2. Blank Plates
1. Blank Plates- The Blank Plates are available to install
on the plenum where an air finger is not required.
Outer Plate
Inner Plate
Blank Plate
Finger
Manifold
Assembly
Baffle
Figure 1-7. Blank Plates (two sizes) and an Air Finger.
6
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SECTION 2
INSTALLATION
SECTION 2
INSTALLATION
WARNING - For gas ovens, after any conversions, readjustments, or service work on the oven:
Perform a gas leak test.
•
•
•
•
Test for correct air supply.
Test for proper combustion and gas supply.
Check that the ventilation system is in operation.
WARNING
Keep the appliance area free and clear of combustibles.
WARNING
The oven must be installed on an even (level) non-flammable flooring and any adjacent walls must be
non-flammable. Recommended minimum clearances are specified in the Description section of this
Manual.
WARNING
Do not obstruct the flow of combustion and ventilation air to and from your oven. There must be no
obstructions around or underneath the oven. Constructional changes to the area where the oven is
installed shall not affect the air supply to the oven.
CAUTION
For additional installation information, contact your local Authorized Service Agent.
NOTE
There must be adequate clearance between the oven and combustible construction. Clearance must
also be provided for servicing and for proper operation.
NOTE
An electrical wiring diagram for the oven is located inside the machinery compartment.
NOTE
All aspects of the oven installation, including placement, utility connections, and ventilation requirements,
must conform with any applicable local, national, or international codes. These codes supersede the
requirements and guidelines provided in this manual.
NOTE
In the USA, the oven installation must conform with local codes. In the absence of local codes, gas
oven installations must conform with the National Fuel Gas Code, ANSI Z223.1. Installed ovens must be
electrically grounded in accordance with local codes, or in the absence of local codes, with the National
Electrical Code (NEC), or ANSI/NFPA70.
NOTE
In Canada, the oven installation must conform with local codes. In the absence of local codes, gas oven
installations must conform with the Natural Gas Installation Code, CAN/CGA-B149.1, or the Propane
Gas Installation Code, CAN/CGA-B149.2, as applicable. Installed ovens must be electrically grounded in
accordance with local codes, or in the absence of local codes, with the Canadian Electrical Code CSA C22.2.
NOTE
In Australia, the oven installation must conform with any requirements of the appropriate statutory authority.
Gas oven installtions must conform with AGA Codes AG311 and AG601.
NOTE
In CE countries, all aspects of the gas supply connection must comply with current IEC/CEE requirements and
with all applicable local, national, and international codes. In addition, four casters are provided to allow the oven
to be more easily moved to the installation location. These casters are intended to simplify pre-installation move-
ment only, and are NOT suitable for use as part of a CE oven installation. During the installation procedure, the
casters MUST be removed, so that the oven can be supported by the supplied 152mm adjustable legs.
7
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SECTION 2
INSTALLATION
NOTE: The oven, when installed, must be electrically
grounded in accordance with local codes, or in the ab-
sence of local codes, with the National Electrical Code
(NEC), or ANSI/NFPA70.
I. UNLOADING
Your Middleby Marshall PS520-Series Oven is shipped
partially assembled. It will arrive in a carton on a crate.
Carton size for a PS520-Series Oven is:
44-1/4″ (1124mm) Long ×
37-1/2″ (953mm) Wide ×
NOTE
There must be adequate clearance between
the oven and any adjacent combustible con-
struction. Clearance must also be provided
for servicing and for operation.
23″ (584mm) High ×
Thecrateandcartonmustbeexaminedbeforesigningthe
Bill of Lading. Report any visible damage to the transport
company, and check for the proper number of crates. If
apparent damage is found, make arrangements to file a
claim against the carrier. Surface Interstate Commerce
Regulations (U.S.A.) require that the claim must be initi-
ated by the consignee within 10 days from the date that
the shipment is received.
CAUTION
Itisrecommendedthattheovenbeplacedunder
a ventilation hood for adequate air supply and
ventilation.
CAUTION
Do not obstruct the flow of ventilation air to and
from your oven. Do not obstruct the fan holes in
the rear of the unit.
PARTS LIST FOR SERIES PS520 GAS OVEN
INSTALLATION KIT
Single Stack Oven
P/N 59182
ITEM
NO.
1
QTY
4
PART NO.
3101908
DESCRIPTION
LEG 4″ AD FT
2
3
4
5
6
7
8
2
1
1
4
1
1
1
48392
48394
48396
51387
59223
INSULATION BOTTOM TRAY
BOTTOM TRAY WELDMENT
TOP COVER
SCREW MSSLT THREAD 8-32 × 1/2, 18-8
OWNER'S OPERATING & INSTALLATION MANUAL
GAS HOSE RESTRAINT CABLE
GAS HOSE
22450-0228
22361-0001
7
8
Figure 2-1. PS520-Series Gas Oven Installation Parts
8
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SECTION 2
INSTALLATION
PARTS LIST FOR SERIES PS520 Gas OVEN
INSTALLATION KIT
Double Stack Oven
P/N 59183
ITEM
NO.
1
QTY
2
PART NO.
48392
DESCRIPTION
INSULATION BOTTOM TRAY
2
3
4
5
6
7
8
1
1
4
4
1
1
2
48394
48396
51387
BOTTOM TRAY WELDMENT
TOP COVER
SCREW MSSLT THREAD 8-32 × 1/2, 18-8
LEG 4″ AD FT
OWNER'S OPERATING & INSTALLATION MANUAL
GAS HOSE RESTRAINT CABLE
GAS HOSE
3101908
59223
22450-0228
22361-0001
7
8
PARTS LIST FOR SERIES PS520 Gas OVEN
INSTALLATION KIT
Triple Stack Oven
P/N 59184
ITEM
NO.
1
QTY
2
PART NO.
48392
DESCRIPTION
INSULATION BOTTOM TRAY
2
3
4
5
6
7
8
1
1
4
4
1
1
3
48394
48396
51387
M3828
59223
BOTTOM TRAY WELDMENT
TOP COVER
SCREW MSSLT THREAD 8-32 × 1/2, 18-8
PIN, ALIGNMENT
OWNER'S OPERATING & INSTALLATION MANUAL
GAS HOSE RESTRAINT CABLE
GAS HOSE
22450-0228
22361-0001
7
8
Figure 2-1 (continued). PS520-Series Gas Oven Installation Parts
9
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SECTION 2
INSTALLATION
Figure 2-5. MODEL PS520 SINGLE OVEN DIMENSIONS
1
4.00
101.6mm
The Opening Height is Adjustable from 2-1/4 inch minimum
to 3-3/4 inch maximum in 1/2 inch increments.
1
10
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SECTION 2
INSTALLATION
Figure 2-6. MODEL PS520 DOUBLE OVEN DIMENSIONS
1
4.00
101.6mm
The Opening Height is Adjustable from 2-1/4 inch mini-
mum to 3-3/4 inch maximum in 1/2 inch increments.
1
2
P/N 59927 is shown in its correct installed position.
11
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SECTION 2
INSTALLATION
Figure 2-7. MODEL PS520 TRIPLE OVEN DIMENSIONS
1
1
The Opening Height is Adjustable from 2-1/4 inch mini-
mum to 3-3/4 inch maximum in 1/2 inch increments.
1
2
P/N 59927 is shown in its correct installed position.
12
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SECTION 2
INSTALLATION
UTILITY ROUGH-IN DIMENSIONS AND POSITIONING
FOR PS520-SERIES OVENS
WARNING
DO NOT USE CONDUIT OR GAS LINE
FOR GROUND CONNECTION.
CAUTION
IT IS RECOMMENDED THAT THE OVEN
BE PLACED UNDER A VENTILATION
HOOD FOR ADEQUATE AIR SUPPLY
AND VENTILATION.
ELECTRIC SUPPLY TO BE
PROVIDED BY CUSTOMER
CIRCUIT BREAKER
Figure 2-9. Typical PS520-Series Oven(s)
Installation
POWER RATING
Separate circuit breaker with lockout/tagout electrical
shutoff for each oven. Wire each oven separately.
15A Amp circuit breaker for 208-240V.
40,000 BTU/hr (11.7 kW/hr.
ELECTRICAL SPECIFICATIONS
SUPPLY WIRE
DOMESTIC: 208V main blower motors, 1 Ph, 1.5 Amp
draw, 50/60 Hz, 208-240V control circuit, 2 pole, 3 wire
system per oven (2 hot, 1 grd).
Supply wire size must be in accordance with the National
Electrical Code (current edition) and must be in compli-
ance with local codes.
Do NOT use conduit for ground.
SUGGESTED
or
If space permits, service should be located near the
control console end of the oven(s) to allow convenient
access to safety switches.
DOMESTIC or EXPORT: 240V main blower motors, 1
Ph, 1.5 Amp draw, 50/60 Hz, 208-240V control circuit, 2
pole, 3 wire system per oven (2 hot, 1 grd).
CAUTION
UNIT MUST HAVE AIR VENT PLATES IN-
STALLEDORWARRANTYWILLBEVOID.
230Vmainblowermotors, 1Ph, 1.5Ampdraw, 50/60Hz,
208-240V control circuit, 2 pole, 3 wire system per oven
(2 hot, 1 grd).
Do NOT use conduit for ground.
II. VENTILATION GUIDELINES
A mechanically driven ventilation system is required for the
PS520SeriesMiddlebyMarshallconveyorizedgas ovens.
Local codes and conditions vary greatly from one area
to another and must be complied with. Following are
the suggested requirements for good ventilation. Please
rememberthesearerecommendationsorguidelines,you
may have a special condition or problem that will require
theservicesofaventilationengineerorspecialist. Proper
ventilation is the oven owner’s responsibility. Improper
ventilation can inhibit oven performance.
Please Note: There are now two “stand off”
‘C’ Channels and the “plate” for “Double
and Triple Ovens” that must be installed in
the field.
13
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SECTION 2
INSTALLATION
These ‘C’ Channel brackets are installed in the vertical
plane using existing screws (Item 6) to support these ‘C’
Channels using the upper and lower Key Hole openings
in the ‘C’ Channels. The ‘C’ Channels are identical and
once installed will allow ample amounts of air through
the cooling fan mounted on the rear side of the oven by
keeping the oven away from the rear wall.
electricalcoderequirements.Copperistherecommended
material for the electrical supply conductors.
IV. ELECTRIC SUPPLY FOR GAS HEATED
OVENS
Power requirements for gas heated ovens are 208 -
240VAC, 1-phase, 3-wire (2 ‘hot’, 1 ground). Electrical
connection is made through a cord and plug. Using
flexiblecable(s)fortheelectricalpowersupplyconductors
requires a 2″ (51mm) strain-relief fitting (not furnished)
to enable safe access to the terminal block from which
oven power is distributed.
III. ELECTRICAL CONNECTION
INFORMATION FOR PS520-SERIES
OVENS.
The supply conductors must be of the size and material
(copper) recommended to provide the current required;
(refer to the data plate for the ampere specifications).
The electric current rating for each conductor supplying
a PS520-Series Oven is 1.5A.
WARNING
Authorized supplier personnel normally
accomplish the connections for the ventilation
system, electric and gas supplies, as arranged
by the customer. Following these connections,
the factory-authorized installer can perform the
initial startup of the oven.
Checktheovendataplate(Figure2-10)beforemakingany
electric supply connections. Electric supply connections
must agree with data on the oven data plate.
NOTE: The electric supply installation must satisfy the
requirements of the appropriate statutory authority, such
as the National Electrical Code (NEC), ANSI/NFPA70,
(U.S.A.); the Canadian Electrical Code, CSA C22.2; the
Australian Code AG601; or other applicable regulations.
ELECTRICAL
INLET
A fused disconnect switch or a main circuit breaker
(customer furnished) MUST be installed in the electric
supply line for each oven; it is recommended that this
switch/circuitbreakerhavelockout/tagoutcapability.The
electricsupplyconnectionmustmeetallnationalandlocal
GAS INLET
Figure 2-11. Junction Connection Box
Figure 2-10. Typical Electric Oven Data Plate
14
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SECTION 2
INSTALLATION
2. Connect a suitable pressure gauge to pipe line or to outlet
pressure tap of gas control concerned, to measure burner
pressure (measuring point must be as near to burner as
possible).
V. GAS SUPPLY
CAUTION
DURING PRESSURE TESTING NOTE THE FOLLOWING:
3. Make sure that the appliance is in operation and the Modu-
1. The oven and its individual shutoff valve must be dis-
connected from the gas supply piping system during any
pressure testing of that system at test pressure in excess
of 1/2 psi (3.45 kPa).
plus® coil is energized with maximum current.
4. If maximum rate pressure needs adjustment, use an 8 mm
wrench to turn adjustment screw for maximum pressure set-
ting (clockwise to increase or counter-clockwise to decrease
pressure), until the desired maximum outlet pressure is
obtained.
2. The oven must be isolated from the gas supply piping
systembyclosingitsindividualmanualshutoffvalvedur-
ing any pressure testing of the gas supply piping system
at test pressure equal to or less than 1/2 psi (3.45 kPa).
5. Disconnect electrical connection of the Moduplus®.
6. Check minimum pressure setting and readjust if necessary.
(SeeAdjustingMinimumPressureSettingforproperadjusting
procedure.)
3. If incoming pressure is over 14" W.C. (35mbar), a sepa-
rate regulator MUST be installed in the line BEFORE the
individual shutoff valve for the oven.
7. Reconnect pressure feedback connection (if appcable).
WARNING: To prevent damage to the control valve regu-
lator during initial turn- on of gas, it is very important to
open the manual shutoff valve very slowly.
8. If minimum and maximum pressures are set, wire the Mo-
duplus® in circuit.
9. Close pressure tap screw.
Aftertheinitialgasturn-on,themanualshutoffvalvemust
remain open except during pressure testing as outlined
in the above steps or when necessary during service
maintenance.
E. Adjusting the Minimum Pressure Setting
1. Disconnect pressure feedback connection (if appcable).
2. Connect a suitable pressure gauge to pipe line or to outlet
pressure tap of gas control concerned, to measure burner
pressure (measuring point must be as near to burner as
possible).
A. Gas Utility Rough-In Recommendations
3. Disconnect electrical connection of the Moduplus®.
The following gas system specifications are STRONGLY
RECOMMENDED. Deviating from these recommendations may
affect the baking performance of the oven.
4. Energize operator, set control in operation and wait until an
outlet pressure is recorded on pressure gauge.
Gas Meter - 650 cfh (307/min) meter
Gas Line
5. If minimum rate pressure needs adjustment, use an 8 mm
wrenchtoturnadjustmentscrewforminimumpressuresetting
(clockwisetoincreaseorcounter-clockwisetodecreasepres-
sure), until the desired minimum outlet pressure is obtained.
•
•
•
•
DEDICATED LINE from the gas meter to the oven
2" (50.8mm) pipe for natural gas
1-1/2" (38.1mm) pipe for propane
Maximum length: 200' (61m). Each 90° elbow equals 7'
(2.13m) of pipe.
6. Check if main burner lights easily and reliable at minimum
pressure.
7. Reconnect pressure feedback connection (if appcable).
8. Close pressure tap screw.
B. Gas Conversion
Where permitted by local and national codes, it is possible to
convert ovens from natural to propane gas, or from propane to
natural gas. Use the appropriate Middleby Gas Conversion Kit
for the specific oven model.
Figure 2-15 - Flexible Gas Hose Installation
1/2" gas
pipe nipple
CAUTION: The terms of the oven’s warranty require all start-
ups, conversionsandserviceworktobeperformed
by a Middleby Authorized Service Agent.
3/4"-1/2"
gas pipe
reducer
Supply
To Gas
Pipe
3/4" gas
pipe nipple
C. PS520 Propane Conversion
Two items have to be changed, to change the oven to LP:
1. Replace main orifices.
1/2" gas
line tee with
pressure tap
90°
Elbow
2. Adjust main gas regulator per instructions below.
Disconnect the manifold union closest to the main burner, and
remove the manifold assembly (four screws). Slide out the mani-
fold assembly (leaving the ignition and sense wires connected).
Replace the main orifices.
Full-Flow
Gas
Shutoff
Valve
Replace the main orifices on the manifold assemblies with the LP
units, and replace the manifold assembly. Reconnect the union.
Individual gas
connection
for each oven
cavity
Flexible
Gas Hose
Quick-
disconnect
device
D. Adjusting the Maximum Pressure Setting
1. Disconnect pressure feedback connection (if applicable).
15
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SECTION 2
INSTALLATION
Figure 2-16. Gas Burner Assembly
G. Maintenance
Gas Burner
Itisrecommendedtocheckyearlytheminimumandthemaximum
setting and readjust them if necessary.
H. Connection
WARNING
Some procedures in this section may require
conversions, readjustments, or service on the oven's
gas system. Before performing these procedures,
=
check that the main gas supply valve and the circuit breaker/
fused disconnect are in the OFF ("O") position. After com-
pleting these procedures, perform a gas leak test before
operating the oven.
CAUTION
Manifold Pressure Tap
The terms of the oven's warranty require all start-ups, conver-
sions and service work to be performed by a Middleby Marshall
Authorized ServiceAgent. The installation, start-up and changes
required when changing from one gas type to another can be
performed ONLY by a certified professional.
Figure 2-17. Burner Assembly
NOTE: Certain safety code requirements exist for the installation
of gas ovens; refer to the beginning of Section 2 for a list of the
installation standards. In addition:
•
In the USA, the installation must conform with local codes,
or in the absence of local codes, with the National Fuel Gas
Code, ANSI Z223.1.
•
In Canada, the installation must conform with local codes, or
intheabsenceoflocalcodes,withtheNaturalGasInstallation
Code, CAN/CGA-B 149.1, or the Propane Installation Code,
CAN/CGA-B 149.2, as applicable.
•
•
In Australia, the installation must conform with AGA Codes
AG311 and AG601, and with any requirements of the
appropriate statutory authority.
Main•
Orifices
In CE countries, the gas supply connection should be ac-
cordingtoEN-203(gasappliancedirective)andtoapplicable
ISO 228-1 or ISO 7-1 recommendations. All aspects of the
gas supply connection must comply with current IEC/CEE
requirements and with all applicable local, national, and
international codes.
Figure 2-18. Gas Valve
Adjustment Screw (5 mm)
for minimum pressure
setting
Adjustment Screw (8
mm) for maximum
pressure
•
For all ovens equipped with casters, the gas line connection
setting
shall be made with:
-
A connector that complies with the Standard for
Connectors for Movable Gas Appliances, ANSI Z21.69
(in USA), or Connectors for Movable Gas Appliances,
CAN/CGA-6.16 (in Canada).
Check the oven’s gas supply requirements to determine the type
of gas to be used with the oven. If the gas type required does
NOT match the local supply:
•
For NorthAmerican installations, a conversion kit is supplied
with the oven to allow operation using propane gas. Refer to
Part B, Gas Conversion, in this section.
•
For CE ovens, directions for converting the oven for use with
other gases are described in Part D.1, Preparation for Use
with Various Gases, in this section.
F. Checkout
After any adjustment, set appliance in operation and observe
through a component cycle to ensure that burner system com-
ponents function correctly.
16
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SECTION 2
INSTALLATION
If the installation will use the supplied gas hose, be sure that the
1/2" to 3/4" gas line fitting is attached. Refer to the instructions
in the gas hose package. One gas line connection method is
shown in Figure 2-15; however, compliance with the applicable
standards and regulations is mandatory.
Inlet and regulated gas pressures can be measured using
a “U” tube manometer at the tap locations shown in Figures
2-15 and 2-16.
1. Checking the Gas Supply (Inlet) Pressure
a. With the main gas supply valve closed and the circuit
breaker/fused disconnect in the OFF ("O") position, open
the inlet pressure tap shown in Figure 2-16 and attach a
manometer to the tap.
b. Depress the safety switches to allow the oven to operate.
c. Openthemaingassupplyvalve. Switchthecircuitbreaker/
fused disconnect to the ON ("I") position.
d. Start the oven according the directions in the Operation
section of this Manual. Adjust the temperature controller
to the maximum setting (316°C).
e. Measure the supply (inlet) pressure.
f. Switch the oven off. Close the main gas supply valve, and
switchthecircuitbreaker/fuseddisconnecttotheOFF("O")
position. Remove the manometer, and close the inlet tap.
g. Compare the measured supply (inlet) pressure to the
nominal pressures shown in Table 1-5 (in the Description
section of this Manual).
If the supply pressure is lower or higher than the nominal
pressure, the reason should be investigated and the gas
supplier contacted.
Fornaturalgasovens, ifthemeasuredsupplypressureislower
than0.247psi, orhigherthan0.363psi, contactthegassupplier.
DO NOT OPERATE THE OVEN or adjust the oven controls.
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SECTION 2
INSTALLATION
NOTES
18
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SECTION 3
OPERATION
SECTION 3
OPERATION
I. CONTROL FUNCTIONS
Figure 3-1. PS520-Series Oven Control Functions
WARNING
A possibility of injury from rotating parts and
electric shock exists in this oven.
Never disassemble or clean the oven with the
BLOWER switch or any other oven control
turned “ON” or “I”. Turn “OFF” or “O” and lockout
or tagout all electric power to the oven before
attempting to clean or service this oven.
19
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SECTION 3
OPERATION
main blower will continue to run after the blower switch
is turned to the “OFF” or “O” position.
II. COMPONENT INFORMATION AND
LOCATION (Figures 3-1 and 3-2)
C. Heat Switch
A. Door Safety Switch
The“HeatSwitch”allowstheburnertoactivate.Activation
is determined by the settings on the Digital Temperature
Controller.
The Door Safety Switch is located at the lower right side
of control panel opening. Opening the control panel door
permits this switch to open, disconnecting power to all
electrical controls.
D. Temperature Controller
The temperature controller is a solid-state, PID type to
maintain the operator-set temperature. The temperature
controller continuously monitors the oven temperature
and turns on the modulating solid state relay controller.
Theheatisonforthetimerequiredtomaintainaconstant
oven temperature.
CAUTION
Do NOT touch the wires going to this safety
switch. Current is always present.
B. Blower Switch
The temperature controller contains a low-limit switch
whichallowstheoventocooldownto200°F(93°C)before
shutting off the blower. A high-limit indication (ALM 1) will
appear on the display if the oven reaches 650°F (343°C).
The blower switch has two positions. The switch must be
“ON” or “I” for the main blowers to come on and permit
the oven to run. The fan circulates the air throughout
the oven and must stay on during baking and during the
cool down cycle above 200°F (93°C) to prevent blower
bearing damage. To protect the blower motor and bear-
ings a thermostatic override is built into the oven. If the
temperature inside the oven is over 180°F (82°C) the
Figure 3-2. Interior View of Control Console
20
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SECTION 3
OPERATION
E. Conveyor
The on-off switch for the conveyor motor is on the con-
trol panel. Also on the control panel is the digital con-
veyor speed control. The digital control can be adjusted
from 1-10 min. bake time (conveyor speed).
Refer to Figure 3-3.
Conveyorspeedismeasuredbytheamountoftimeittakes
for an item to go through the bake chamber of the oven.
MEASURING CONVEYOR SPEED.
See Figures 3-4 and 3-5.
To check conveyor speed, place a product item at the
entrance end of baking chamber as shown. Time how
long it takes for the leading edge of the item to go from
the entrance end of the baking chamber to the exit end.
This should be the conveyor speed shown on the con-
veyor speed digital control.
Figure 3-3. Conveyor Speed Digital Control
NOTE: In Figures 3-4 and 3-5, the oven shown is with
the conveyor running right to left.
WARNING
Possibility of injury from rotating parts and
electrical shock exist in this oven.
Never disassemble or clean the oven with the
blower switch or any other part of the oven
turned “ON” or “I”. Turn “OFF” or “O” and lock-
out or tagout all electrical power to the oven
before attempting to clean or service
this oven.
Figure 3-4. Product at entrance end of baking
chamber – BEGINNING OF TIMING
Figure 3-5. Product at exit end of baking
chamber – END OF TIMING
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SECTION 3
OPERATION
4. Set the temperature controller to the desired baking
temperature.
WARNING
OVEN MUST BE KEPT CLEAR OF
COMBUSTIBLES AT ALL TIMES.
NOTE: For complete temperature controller operation
instructions refer to Step C.
5. Turn the HEAT switch (Figure 3-6) to the “ON” or “I”
position. Wait for the “Heat ON” light to turn on.
III. STEP-BY-STEP OPERATION
A. Startup Procedures
Daily Startup
6. Ovenwillreachabakingtemperatureof500°F(232°C)
in approximately 20 minutes. Allow the oven to cycle for
30minutesafterithasreacheddesiredbaketemperature.
The oven is now ready for baking.
1. Turn the BLOWER switch (Figure 3-6) to the “ON” or
“I” position. This starts the main blower fan and the cool-
ing fans. The blower circulates air through the air fingers
and must stay on during the cooking or baking process.
Power Failure
In case of power failure, turn off all switches and remove
product. After power has been reestablished follow
normal startup procedure.
2. Check to see if the cooling fans (see Figure 1-8) are
operatingwhentheblowerswitch(seeFigure3-6)isturned
“ON” or “I”. The cooling fans cool the control components
and blower motor. The cooling fans, located at the rear
of the oven blows air into and through the cabinet. Air is
exhausted through the front of the cabinet and also out
the front of the oven. Refer to Daily Maintenance Section
for fan intake checking procedure.
B. Shutdown Procedure
1. TurntheBLOWERandHEATswitchesto“OFF”or“O”.
NOTE: The blowers will remain on until the oven tem-
perature cools down to 200°F (93°C) at which time they
will stop automatically.
IMPORTANT NOTE
2. Make certain that there are no products left on the
conveyor inside the oven. Turn the CONVEYOR switch
to “OFF” or “O”.
The cooling fan operates when the BLOWER
switch is turned “ON” or “I”. It must operate to
keep the control console below 140°F (60°C).
3. TurntheCONVEYORswitch(Figure3-6)tothe“ON”or
“I” position. This starts the conveyor belt moving through
the oven. Set the conveyor speed for the desired baking
time. Refer to the following Procedures E, F and G.
22
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SECTION 3
OPERATION
Figure 3-6. Control Panel
23
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SECTION 3
OPERATION
7. Wait for the oven to heat to the setpoint temperature.
Higher setpoint temperatures will require a longer wait.
The oven can reach a temperature of 500°F (232°C) in
approximately 15 minutes.
IV. NORMAL OPERATION - STEP-BY-STEP
A.Daily Startup Procedure
1. Check that the circuit breaker/fused disconnect is in the
on position.
8. (Optional)PresstheTem-
perature ( ) key to show
the Actual Temperature
2. Turn the "BLOWER"
wait
for
(
) switch to the
in the display, and wait
for the "ACTUAL TEMP"
“ON” ("I") position.
lighttoturnon. Thisallows
you to monitor the oven
temperature as it rises to
the setpoint.
3. Turn the "CONVEYOR"
9. Allowtheoventopreheatfor10minutesafterithasreached
the set point temperature.
(
)switchtothe“ON”
("I") position.
B. DAILY SHUTDOWN PROCEDURE
1. Turn the "HEAT" (
+
4. If necessary, adjust the
conveyor speed setting
) and "BLOWER" (
) swit-ches to the "OFF"
("O") position. Note that
the blowers will remain in
operation until the oven
hascooledtobelow200°F
(93°C).
by pressing the
or
or
pushbuttons on the
conveyorspeedcontroller
to change the displayed
bake time.
5. Adjust the temperature
controller to a desired set
temperature,ifnecessary.
2. Make certain that there
arenoproductsleftonthe
conveyorinsidetheoven.
Turn the "CONVEYOR" (
) switch to the "OFF"
wait
for
+
•
Press the Set Point
and Unlock keys at
the same time. Wait
for the "SET PT" light
to turn on.
("O") position.
3. After the oven has cooled and the blowers have turned to
the “OFF” or “O” position, switch the circuit breaker/fuse
disconnect to the “OFF” or “O” position.
•
Press the Up Arrow
and Down Arrow
Keysasnecessaryto
adjust the set-point.
IMPORTANT
or
On gas ovens, if the "HEATON" light will not illuminate, OR
if the oven does not heat, the gas burner may not have lit.
Turnthe"HEAT"( ),"BLOWER"( ),and"CONVEYOR"
(
) switches to the "OFF" ("O") position. Wait for AT
LEAST FIVE MINUTES before restarting the oven. Then,
repeat the Daily Startup procedure.
6. Turn the "HEAT" (
)
switch to the "ON" ("I")
position, and wait for the
"HEAT ON" light to turn
on.
CAUTION
In case of power failure, turn all switches to the “OFF”
("O")positionandremovetheproduct. Afterthepower
has been restored, perform the normal startup pro-
cedure. IF THE OVEN WAS SWITCHED OFF FOR
LESSTHAN 5 MINUTES, WAITFORATLEASTFIVE
MINUTES BEFORE RESTARTING THE OVEN.
wait
for
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SECTION 3
OPERATION
Display
"HEAT ON" Light
Lights when the
burner is in
Shows the Set Point
or the Actual Tem-
perature in degrees
Fahrenheit (F) or
Celsius (C).
operation.
"SP LOCK"
Light
Lights when the set
point is locked out
from changes. This
setting can only be
changed by service
personnel.
"SET PT" (set-
point) Light
Lights when the set
point is shown in
the display.
OVERTEMP
Light
Lights when the oven
temperature is greater
than 650°F (343°C).
Refer to Quick Refer-
ence: Troubleshoot-
ing in this section.
"ACTUAL TEMP"
Light
Lights when the Actual
Temperature is shown
in the display.
Service Key
Service use
only.
Temperature Key
Press this key once
to view the Actual
Temperature in the
Display.
Set Point Key
Press this key togeth-
er with the Unlock Key
to allow the Set Point
to be changed.
Changes can only be
made for 60 seconds.
Unlock Key
Press this key togeth-
er with the Set Point
Key to allow the Set
Point to be changed.
Changes can only be
made for 60 seconds.
Up Arrow and Down
Arrow Keys
Press these keys to adjust
the Set Point up or down.
If the Set Point will not
change, refer to Set Point
Key and Unlock Key in this
section.
25
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SECTION 3
OPERATION
V. QUICK REFERENCE: TROUBLESHOOTING
SYMPTOM
PROBLEM
SOLUTION
The oven temperature ex-
ceeded 650°F (343°C), and
theburnerwasautomatically
shut down.
•
Follow the procedures under Daily Shutdown Procedures in this
section to shut down the oven. Contact your Middleby Marshall
Authorized ServiceAgent to determine and correct the cause of
the condition to prevent damage to the oven.
light is lit, food product is
undercooked
Oven will not
turn on at all
Electrical power may not
be reaching the oven, or
the controls may be set
incorrectly.
•
•
Check that the circuit breaker/fused disconnect is turned on.
Check that the "BLOWER" ( ) Switch is in the “ON” ("I") posi-
tion.
The oven did not reach
200°F (93°C) within 15
minutes of startup, and the
oven has stopped heating.
•
Turn the "HEAT" ( ), "BLOWER" ( ), and "CONVEYOR" (
)switches to the "OFF" ("O") position.
•
•
Wait for AT LEAST FIVE MINUTES before restarting the oven.
Repeat the Daily Startup procedure.
appears in display,
oven is not heating
Controls may be set incor-
rectly.
•
•
Check that the Set Point is correctly set.
Oven will not heat
Check that both the "BLOWER" ( ) and "HEAT" ( ) Switches
are in the “ON” ("I") position.
•
If the oven still will not heat,turn the "HEAT" ( ), "BLOWER" (
), and "CONVEYOR" (
tion.
)switches to the "OFF" ("O") posi-
•
•
Wait for AT LEAST FIVE MINUTES before restarting the oven.
Repeat the Daily Startup procedure. Check that the Set Point
is above 200°F (93°C).
Oven is operating, but little
or no air is blowing from air
fingers
Air fingers may have been
reassembled incorrectly
after cleaning.
•
•
Turn the oven to the “OFF” or “O” position, and allow it to cool.
Disconnect electrical power to the oven.
RefertoSection4,Maintenance,forinstructionsonreassembling
the air fingers.
Conveyor moves with a
jerky motion, or will not
move at all
Conveyor may be jammed
on an object in the oven, or
conveyor belt or drive chain
tension may be incorrect.
•
Turn the oven to the “OFF” or “O” position, and allow it to cool.
Disconnect electrical power to the oven.
•
•
Check if the conveyor is blocked by an object inside the oven.
Refer to Section 4, Maintenance, for instructions on checking
the conveyor and drive chain tension.
Food products are over-
cooked or undercooked.
Controls may be set incor-
rectly.
•
Check that the set temperature and bake time settings are cor-
rect.
IF THESE STEPS FAIL TO RESOLVE THE PROBLEM, CONTACT YOUR LOCAL MIDDLEBY MARSHALL
AUTHORIZED SERVICE AGENT. A SERVICE AGENCY DIRECTORY IS SUPPLIED WITH YOUR OVEN.
26
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SECTION 4
MAINTENANCE
SECTION 4
MAINTENANCE
WARNING
Before ANY cleaning or servicing of the oven, perform the following procedure:
1. Switch off the oven and allow it to cool. Do NOT service the oven while it is warm.
2. Turn the full-flow gas safety valve to the off position.
3. Turn off the electric supply circuit breaker(s) and disconnect the electric supply to the oven.
4. If it is necessary to move a gas oven for cleaning or servicing, disconnect the gas supply before moving the oven.
When all cleaning and servicing is complete:
4. Turn on the full-flow gas safety valve. Test the gas line
connectionsforleaksusingapprovedleaktestsubstances
or thick soap suds.
1. If the oven was moved for servicing, return the oven to its
original location.
5. Turn on the electric supply circuit breaker(s).
2. Reconnect the gas supply.
3. Reconnect the electrical supply.
6. Perform the normal startup procedure.
WARNING
Possibility of injury from rotating parts and electrical
shock exist in this oven. Turn off and lockout or tagout
electrical supply to oven(s) before attempting to disas-
semble, clean or service oven(s). Never disassemble
or clean the oven with the blower switch or any other
part of the oven turned on.
WARNING
Before performing any maintenance work or cleaning,
turn main power switch off.
CAUTION
When cleaning do not use any abrasive cleaning
materials or water spray, wipe clean only. Never use a
water hose or pressurized steam cleaning equipment
when cleaning this oven.
NOTICE
If the oven is to be removed from its installed location
for servicing, perform the following procedure:
1. Switch off the oven and allow it to cool. Do NOT
service the oven while it is warm.
2. Turn off main circuit breakers and disconnect con-
nector from oven.
3. Move oven to desired location for servicing.
4. When servicing is complete, move oven to original
location.
5. Adjust legs to level oven.
6. Connect electrical connectors to oven.
7. Turn on main circuit breakers.
8. Follow normal startup instructions.
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SECTION 4
MAINTENANCE
D. Crumb Pans (Figure 4-2)
I. MAINTENANCE - DAILY
A. Exterior
WARNING
Everyday you should clean the outside of the oven with
a soft cloth and mild detergent.
Crumb pan is extremely hot while oven
is operating. Allow oven to cool before
removing crumb pan.
WARNING
Never use a water hose or pressurized steam
cleaning equipment when cleaning the oven.
Whentheoveniscoolremoveandcleanthecrumbpanat
each end of the oven. Each crumb pan can be removed
by sliding it out, as shown in Figure 4-2. Reinstall the
crumb pans after cleaning.
B. Cooling Fan
1. ONECOOLINGFANGRILLEATTHEREAROFTHE
OVEN MUST BE CLEANED DAILY - Clean grille with a
stiff nylon type brush.
2. Check the air intake of the cooling fan daily. The best
time to check is right after starting the oven.
IMPORTANT NOTE
Thecoolingfanoperateswhentheblowerswitch
is turned to “ON” (“I”). It must operate to keep the
electrical control cabinet below 140°F (60°C).
Figure 4-1. Oven Cooling Fans
WARNING
IF FAN BLADE IS NOT ROTATING, BROKEN,
OR FAN ASSEMBLY IS MISSING FROM MAIN
BLOWERMOTORSHAFT,DONOTOPERATE
OVEN. REPLACE COOLING FAN BLADE
BEFOREOPERATINGOVEN.Seriousdamage
could be done to the burner blower motor and/
or solid-state electrical components if oven is
operated while cooling fan is not running or vent
grille is plugged.
3. Using a stiff nylon brush clean control compartment
vent grille.
C. Conveyor Belt (Figure 4-2)
Everyday, just after starting the oven, stand at the un-
loading end of the conveyor, and with a brush, remove
foodparticles(crumbs, etc.)clingingtotheconveyorbelt,
brushing them into the crumb pan.
Figure 4-2. Conveyor Belt and
Crumb Pan Cleaning
28
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SECTION 4
MAINTENANCE
You can order non-caustic cleaner from your local
authorized Middleby Marshall Parts Distributor in the
quantities listed:
II. MAINTENANCE - MONTHLY
NOTE: The oven interior may require cleaning more
thanonceamonthdependingonthevolumeofbaking.
To clean the interior, you have to disassemble some
parts of the oven.
Part #
Quantity
27170-0244
27170-0246
Case of Quarts (6)
Case of Gallons (4)
When cleaning your Series PS520 Oven note the
following:
A. Removing Conveyor From Oven For Cleaning
1. Remove entry and exit trays.
PRECAUTIONS-
1. Do not use excessive water or saturation of oven
insulation will occur.
2. Loosen(donotremove)twoscrewsonhousingguard.
3. Remove motor housing guard.
2. Do not use a caustic oven cleaner or the aluminized
finger manifold surfaces will be severely damaged.
4. Lift conveyor and remove chain.
When cleaning your oven, first remove all heavy debris
with a vacuum cleaner. Use a damp cloth for light clean-
ing. For heavier cleaning of baked on grease and carbon
deposits use a non-caustic cleaner that will not react with
the aluminized finger manifold surfaces.
5. Liftothersideofconveyorandpushtowardotherside.
Figure 4-3.
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SECTION 4
MAINTENANCE
6. Remove conveyor as shown.
Figure 4-6.
Figure 4-4.
Figure 4-7.
CAUTION
Figure 4-5.
Be careful not to bump the drive sprocket
while handling the conveyor, to avoid
damaging the drive shaft.
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SECTION 4
MAINTENANCE
B. Air Fingers Disassembly For Cleaning
1. As the air fingers are removed use a felt pen to mark
all parts of the fingers. This includes the finger manifold,
inner plate and the outer plate (refer to Figure 1-9). If a
blankorchokeplateisused,markthatplatealso.Fingers
are marked in the order shown; as viewed from the front
of the oven. (The marks for an upper oven should be
preceded with a “U”, example UB1, UT2, etc.)
T1
B1
T2
B2
T3
B3
Standard Fingers
2. Slide blank plates straight out.
Figure 4-9.
4. With air fingers out, place them in an upright position
to remove the outer plate.
5. Gently step on the lip of the finger and pull the outer
plate off.
Figure 4-8.
3. Remove air fingers.
NOTE: Some oven users require a custom finger ar-
rangement where the quantity of air fingers may vary.
You can remove top and bottom fingers and blank
plates from each or either end. It is highly recommended
that each finger be marked before removing so it is
placed in exactly the same position when reassembled
(refer to step 1).
Remove the air fingers, pull the finger at the back side
- pull straight out.
Figure 4-10.
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SECTION 4
MAINTENANCE
6. Toremovetheinnerplate,pulltheplateoutandthenup.
Figure 4-13. Standard Upper Finger
C. Reassembly of Air Fingers
1. Air fingers are made up of one inner plate, one outer
plate and the finger housing manifold. Be sure to match
up the markings (T1, T2, T3, etc.) on all the parts of the
Figure 4-11.
7. The outer finger plate is stainless and may be cleaned
by either soaking in a hot, strong detergent solution or
using a caustic cleaner. The conveyor belt can also be
air fingers as you are reassembling.
Figure 4-14.
2. Reassemble the inner plate. Keep your fingers clear
so you won’t pinch them. The inner plate of a finger will
only go in one way because of its design.
3. Replace the outer plate by placing your hands flat on
the top of the plate and pushing down. Keep your fingers
clear so you won’t pinch them.
Figure 4-15.
cleaned in the same way.
Figure 4-12. Standard Lower Finger
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SECTION 4
MAINTENANCE
4. Replace the air fingers by pushing in at the back side.
Remember to replace them according to the numbers
marked on them when they were removed. They must
go back in the same way they came out.
IMPORTANT: When inserting fingers the tab on
the outer plate must be in the groove as shown
in Figure 4-18. There is a blocking tab on the
outsideofthegroovewhichwillpreventinserting
thefingerinthegrooveiftheouterplateismoved
away from the flange of the finger manifold.
Figure 4-16.
Extended Lip
Tab on
Outer Plate
Flange of
Finger Manifold
Tab on
Outer Plate
Figure 4-17.
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SECTION 4
MAINTENANCE
5. Install fingers and blank plates correctly with edges
interlocked and no space between edges.
Incorrect - Too
Much Space
Top Finger
Blank Plate
Tab on Outer Plate of Finger
Located in Groove
Incorrect - Too
Much Space
Top Finger
Blank Plate
Tab on Outer Plate of Finger
Located in Groove
Correct - Edges
Overlap Com-
pletely
Top Finger
Blank Plate
Tab on Outer Plate of Finger
Located in Groove
Figure 4-18.
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SECTION 4
MAINTENANCE
D. Reinstall End Plugs
1. Reinstall lower end plug. Be sure to tighten the wing
screw on the end plug.
2. Reinstall conveyor.
3. Reinstall upper end plug. Be sure to tighten two wing
screws on the end plug.
Figure 4-19.
Figure 4-20.
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SECTION 4
MAINTENANCE
E. Conveyor Reassembly Into Oven
F. Checking Conveyor Belt Tension
1. Lift conveyor and position it in oven as shown.
WARNING
NOTE:Conveyormaybeinsertedintoeitherendofoven.
If it is to be installed from the non-drive end of the oven
the drive sprocket assembly must be removed as shown
in conveyor disassembly section.
Ovenconveyorbeltmustbecoolwhenadjusting
belt. Do not adjust belt if HOT.
1. With the conveyor assembly in the oven, stand at one
endofconveyorandchecktensionbyliftingtheconveyor
belt at the center of the oven chamber opening. The belt
should not lift higher that 1″ to 2″ (75mm to 102mm).
2. If conveyor belt is still not under proper tension, an
entirelinkmustberemoved. Usethefollowingprocedure
“H. Conveyor Belt Link Removal” to remove a link. If
conveyor belt is under proper tension proceed directly
to “J. Attaching Drive Chain”.
Figure 4-21.
2. Reinstall the conveyor extension.
Conveyor Extension
Figure 4-23.
Figure 4-22.
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SECTION 4
MAINTENANCE
G. Conveyor Belt Link Removal
4. Unhook the link to be removed.
1. Using long nose pliers, an entire link can be removed
with the conveyor assembly either in or out of the oven.
Position master links at end of conveyor as shown in
Figure 4-24.
5. Pull up on the belt link section and remove. Do not
discard the link removed as it may be used for making
spare master links.
NOTE: If a section of the conveyor belt is being replaced
it should be done now. Remove the links that need re-
placing and use the section of conveyor belt furnished
in your installation kit to replace them.
Master
Links
Figure 4-24.
2. Using long nose pliers, unhook master links at left
end of conveyor as shown in Figure 4-25.
Figure 4-27.
NOTE: Before connecting the inside master links, notice
thattheselinkshaveacorrectposition(Figure4-28). The
link at the right is in the correct (horns up) position for
inserting into the conveyor belt. The horns facing down
Correct
Position
Incorrect
Position
Figure 4-25.
3. Remove the outside master links on the right and
left sides of the conveyor belt as shown in Figure 4-26.
are in the incorrect position.
Figure 4-28.
Figure 4-26.
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SECTION 4
MAINTENANCE
6. Reconnect the inside master links (Figure 4-29.)
H. Attaching Drive Chain
1. If drive sprocket assembly was removed reassemble
it into the conveyor drive shaft. Be sure flat on end of
drive shaft aligns with set screw in conveyor shaft collar.
Once in place tighten 3/32″ set screw.
2. Lift conveyor and install drive chain to conveyor drive
sprocket and motor sprocket.
Figure 4-29.
NOTE: The outside master links have right and left sides
to them. The right edge master link has an open hook
facing you as shown in Figure 4-30. This will match up
with the outer edges of the conveyor belt. Remember
this hook travels backwards on the conveyor.
Direction of travel
Figure 4-32.
3. The angle plate located on the underside of the con-
veyor must be against the lower end plug. This is true
on both sides of oven.
Figure 4-30.
7. Reconnect the outside master links.
8. Replace all parts removed from the oven.
Crumb Pan
Mounting
Bracket
Lower End Plug
Figure 4-33.
Figure 4-31.
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SECTION 4
MAINTENANCE
4. Reattach conveyor guard to control panel and secure
two screws.
A. Electrical Terminals
Open the control cabinet door by removing the three
screwsfromthecontrolcabinetdoor.Tightenallelectrical
control terminal screws including the electrical contactor
terminal screws as shown in Figure 4-35.
Install both upper end plugs.
Figure 4-34.
Figure 4-35.
B. Ventilation
III. MAINTENANCE - EVERY 3 MONTHS
Check that the air circulation throughout the oven is not
blocked and is working properly.
WARNING
Shut OFF all electrical power and lock/tag out
the switch before attempting maintenance work.
IV. MAINTENANCE - EVERY 6 MONTHS
A. Check brushes on D.C. conveyor motor, when worn
to less than 1/10″ (2.4mm), replace the brushes.
NOTE:Itisrecommendedthatthe3-monthmaintenance
be performed by an authorized Middleby Marshall
technician.
B. Check your oven venting system.
C. Inspect and clean the burner nozzle and the spark
electrode assembly.
IMPORTANT NOTICES:
• Installation of replacement parts requiring access
to the interior of the oven is permitted only by an
authorized service technician.
• If there are any problems with the operation of
the oven, the authorized service technician must
be called.
• It is suggested to obtain a service contract with
a manufacturer’s authorized service technician.
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SECTION 4
MAINTENANCE
KEY SPARE PARTS KIT
parts that can reduce serious downtime and loss of pro-
duction, if a failure occurs.
An oven can be purchased with a Key Spare Parts Kit
(Figure 4-36). (The kit can be purchased when the oven
is ordered, or later, from a Middleby Marshall Authorized
Parts Distributor). The kit contains many of the crucial
Replacement parts for this kit can be purchased from
your Middleby Marshall Authorized Parts Distributor.
PS520-SERIES GAS OVEN KEY SPARE PARTS KIT (Figure 4-36)
ITEM
1
PART NO.
28041-0011
58390
ENGLISH DESCRIPTION
QUANTITY
Contactor, DP 25A 208/240V
Motor, Conveyor Drive w/Magnet
Board, Amplifier Signal, 4-20VDC
XFMR, 240V PRI 24V 65VA SEC
Thermocouple, Type “J” Shielded 2.50 x 120
Filter, RFI
1
1
1
1
3
1
1
1
3
3
1
2
3
60671
4
32108
5
33812-5
33813
6
7
38185
Assembly, Pickup Sensor
8
41872
Transformer, 240V (P), 24V (S) 25VA
Switch, Rotary and Mounting Adapter
Block, Contact
9
44696
10
11
44697
45644
Breaker, Circuit 240V 1A
12
13
14
15
16
17
18
19
48455
50239
60598
50794
47321
58323
60679
36451
Ignitor, Single Rod PS536
Ignition, Spark Module 24VAC 50/60 Hz
Switch, Air .13″ WC
1
1
1
1
1
1
1
1
Relay, 240VAC 2P1S
Control, Combo 4-20MA, Burst
Controller, Digital w/o Dip Switch
Valve, Gas Modulating
Fan, Cooling 230VAC 295 CFM
20
21
22
50240
59002
52244
Ignition Cable, 25″
Inshot Burner
Main Blower
1
2
2
21
2
20
7
1
5
3
4
15
8
9
10
12
11
13
19
22
16
14
5
18
17
Figure 4-36.
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SECTION 5
TROUBLESHOOTING
SECTION 5
TROUBLESHOOTING
PROBLEM:
PROBLEM:
OVEN BLOWER AND CONVEYOR OPERATE,
YET THE OVEN IS NOT HEATING
PRODUCTS ARE OVERCOOKED
OR UNDERCOOKED
Reset the temperature controller
to a new setting (above 200°F),
after turning the BLOWER switch
to off for 30 seconds.
Check for correct
setting on tempera-
ture controller.
Check for correct
setting of conveyor
speed control.
Turn temperature
control to correct
setting.
Start the oven again. If the oven still does not
heat, call your Middleby Marshall Service Agency.
Set the conveyor speed
control at correct setting.
Verify the food prepa-
PROBLEM:
ration process.
CONVEYOR WILL NOT HOLD PROPER SPEED
OR WILL NOT RUN AT ALL
If products still cook incorrectly,
call your Middleby Marshall
Service Agency.
Check whether the conveyor is
jammed on something in oven.
PROBLEM:
OVEN DOES NOT HEAT
Check for proper tension of conveyor drive
chain and conveyor belt. Refer to Section 4 for
correct procedure.
Check to see if both BLOWER
switch and HEAT switch are in
the “ON” or “I” position.
Check that the conveyor
drive sprocket is tight.
If oven does not heat, call your
Middleby Marshall Service Agency.
If conveyor still does not run correctly, contact
your Middleby Marshall Service Agency.
PROBLEM:
BLOWER MOTOR IS RUNNING, YET LITTLE
OR NO AIR BLOWS FROM AIR FINGERS
PROBLEM:
OVEN DOES NOT TURN ON WHEN ITS
SWITCHES ARE TURNED ON
Air fingers reassembled incorrectly,
Check that all electric supply switches are set to
the “ON” or “I” position. Then, start the oven.
after cleaning.
Assemble air fingers correctly, after cleaning.
Refer to Section 4 procedure, or call your
Middleby Marshall Service Agency.
If oven still will not start, contact your Middleby
Marshall Service Agency.
41
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SECTION 5
TROUBLESHOOTING
NOTES
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SECTION 6
ELECTRICAL SCHEMATICS
SECTION 6
ELECTRICAL SCHEMATICS
43
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WARNING
Improper installation, adjustment, alteration, service or maintenance
can cause property damage, injury or death. Read the installation,
operating and maintenance instructions thoroughly before
installing or servicing this equipment.
NOTICE
During the warranty period, ALL parts replacement and servicing should be performed
by your Middleby Marshall Authorized Service Agent. Service that is performed by
parties other than your Middleby Marshall Authorized Service Agent may void your
warranty.
NOTICE
Using any parts other than genuine Middleby Marshall factory manufactured parts
relieves the manufacturer of all warranty and liability.
NOTICE
Middleby Marshall reserves the right to change specifications at any time.
Middleby is proud to support the Commercial Food Equipment
Service Association (CFESA). We recognize and applaud
CFESA's ongoing efforts to improve the quality of technical
service in the industry.
MiddlebyCookingSystemsGroup•1400ToastmasterDrive•Elgin, IL60120•USA•(847)741-3300•FAX(847)741-4406
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