Service, Parts, Operation & Installation Manual 02/2006

Service, Parts, Operation & Installation Manual 02/2006
Plus Twenty-Four™
PRESSURELESS STEAM COOKER
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.
FOR YOUR SAFETY
Do not store or use gasoline or other
flammable vapors or liquids in the vicinity of
this or any other appliance.
MODEL
ST-24
COVERING
• Installation
• Operation
• Service and Parts
INSTALLATION, OPERATION, AND MAINTENANCE MANUAL
An Employee-Owned Company
35 Garvey Street•Everett, MA 02149 4422 USA
Tel: (617) 387-4100•Fax: (617) 387-4456
Fax Outside MA: 1-800-227-2659
E-Mail: CUSTSERV@MFII.COM
Form No. S-4627
Rev. A
02/05
Printed in U.S.A.
TABLE OF CONTENTS
PARAGRAPH
PAGE
PARAGRAPH
SECTION 1 INTRODUCTION
1.1
1.2
1.3
Description .......................................... 1-1
Basic Functioning ................................ 1-1
Service ................................................ 1-1
5.1
5.2
5.3
5.4
SECTION 2 INSTALLATION
2.1
2.2
2.3
2.4
2.5
2.5.1
2.5.2
2.5.3
2.6
3.1
3.2
3.2.1
3.2.2
3.2.3
3.2.4
3.3
3.4
3.4.1
3.4.2
3.5
5.4.1
5.4.2
5.4.4
5.4.4.1
5.4.4.2
5.4.5
5.4.6
5.4.7
5.4.8
Assembly ............................................ 2-1
Setting in Place ................................... 2-1
Mechanical Connections ..................... 2-1
Water Connections ............................. 2-1
Installation Check-Out ......................... 2-1
Initial Control Settings ......................... 2-2
Cooker Check-Out .............................. 2-2
Shut-Down Procedure ......................... 2-2
Reversing the Doors ........................... 2-2
SECTION 3
5.4.9
5.4.10
5.4.11
OPERATION
Operating Controls and Indicators ...... 3-1
Operating Procedures ......................... 3-1
Steam Source Operation ..................... 3-1
Preheating ........................................... 3-1
Cooking ............................................... 3-1
Shut-Down Procedure ......................... 3-1
Cleaning .............................................. 3-2
Drainage ............................................. 3-2
Cooking Compartment Drainage ......... 3-2
Drip/Spill Trough Drainage .................. 3-2
Test Kitchen Bulletin ........................... 3-3
General ............................................... 5-1
Trouble-Shooting Guides .................... 5-1
Electrical Fault Isolation ...................... 5-1
Electrical Trouble-Shooting
Procedures ..................................... 5-1
Incoming Power .................................. 5-2
Electrical Inspection ............................ 5-2
60-Minute Timer .................................. 5-3
Timer Contacts .................................... 5-3
Timer Motor ......................................... 5-3
Door Interlock Switch ............................ 5-6
Steam Solenoid Valves ......................... 5-6
Indicator Lights ..................................... 5-6
Cooking Compartment Thermostatic
Switch .............................................. 5-6
Buzzer .................................................. 5-6
Cold Water Condenser Circuit ............... 5-7
Wiring ................................................... 5-7
SECTION 6 MAINTENANCE
6.1
6.2
6.2.1
6.3
6.3.1
6.3.2
6.3.3
6.3.4
6.3.5
SECTION 4 PRINCIPLES OF OPERATION
4.1
4.2
4.2.1
4.2.2
4.2.3
4.3
4.3.1
4.3.1.1
4.3.1.2
4.3.1.3
4.3.1.4
4.3.1.5
PAGE
SECTION 5 TROUBLE-SHOOTING
General ............................................... 4-1
Plumbing Circuits ................................ 4-1
Steam Inlet Line .................................. 4-1
Steam Exhaust and Drain Lines .......... 4-1
Steam Exhaust Condensing System ... 4-1
Electrical Circuits ................................. 4-2
Control Circuit Components ................ 4-3
60 Minute Timer .................................. 4-3
Indicator Lights .................................... 4-3
Buzzer ................................................. 4-3
Door Interlock Switch .......................... 4-3
Thermostatic Switch ............................ 4-3
General ............................................... 6-1
Preventive Maintenance ...................... 6-1
Cooking Compartment Cleaning ......... 6-1
Repair and Replacement .................... 6-1
Door Latch Tension Adjustment .......... 6-1
Door Handle Tension Adjustment ....... 6-2
Door Gasket Replacement .................. 6-2
Exterior Panel Removal ...................... 6-2
Steam and Water Solenoid Valve
Replacement ................................... 6-2
SECTION 7 ILLUSTRATED PARTS LIST
7.1
7.2
7.3
7.4
iii
General ............................................... 7-1
Ordering Information ........................... 7-1
Index of Illustrated Parts List ............... 7-1
Illustrated Parts List ................. 7-2 thru7-6
LIST OF ILLUSTRATIONS
FIGURE
PAGE
FIGURE
SECTION 2 INSTALLATION
2-1
Typical door layout .............................. 2-3
5-1
5-2
SECTION 3 OPERATION
3-1
Controls and Indicators ....................... 3-2
Wiring Diagram, Model ST-20 ............... 5-4
Schematic Diagram, Model ST-20 ........ 5-7
SECTION 7
7-1
7-2
7-3
7-4
SECTION 4 PRINCIPLES OF OPERATION
4-1
PAGE
SECTION 5 TROUBLE-SHOOTING
Pictorial Diagram—
Steam and Water Circuits ............... 4-2
ILLUSTRATED PARTS LIST
Cabinet Assembly ............................... 7-3
Door Assembly .................................... 7-4
Control Panel Assembly ...................... 7-5
Condenser Assembly .......................... 7-6
LIST OF TABLES
TABLE
PAGE
SECTION 3
3-1
TABLE
OPERATION
PAGE
SECTION 5 TROUBLE-SHOOTING
Controls and Indicators ....................... 3-3
5-1
5-2
iv
General Trouble-Shooting Guide ........ 5-1
Electrical Fault Isolation Guide ............ 5-3
1. INTRODUCTION
This service and parts manual contains general information, installation operation, principles of operation,
trouble-shooting, and maintenance information for Market Forge ST-20 Pressureless Stean Cookers. Also
included is a part list in which each replaceable part is identified and shown in an accompanying exploded
view.
1.1 DESCRIPTION
The ST-24 is a pressureless steam cooker consisting
of two independently controlled compartments enclosed
in a single cabinet. Each compartment is equipped with a
separate three-piece door with inner gasket plate isolated
from the exterior surface. Door latches operate by action
for positive sealing of inner door. Steam and steam-condensing circuits are electrically controlled. Operating controls are displayed on a single front-mounted panel and
include separate timers with indicator lights for selection
of constant steam or 60-minute-long duration cooking.
time period. At the end of the set interval, timer contacts
switch to shut off the cooking operation and sound a signal buzzer. The buzzer is silenced by returning the timer
dial to the OFF position. In the constant steam mode,
operation will be continuous.
Steam emitted from the compartment along with liquid cooking drainage is directed through a drain screen
inside the compartment into the cooker drain line. A cold
water solenoid valve connected into the cooker drain
line is automatically actuated by a thermostatic switch
in the cooking compartment drain to condense the steam
to water prior to discharge into the drain.
A separate steam source is required for operation of
the Pressureless Cooker and is normally purchased with
it, please refer to the respective manual for guidance.
1.3 SERVICE
1.2 BASIC FUNCTIONING
The Model ST-20 may be operated with only one compartment in use; or both may be used simultaneously.
Each compartment is equipped with identical controls, allowing selection of constant steam or 60-minute timer operation. The cooker becomes operational when it is set to
constant steam, or the timer is set at the desired cooking
time and the compartment door is closed. The indicator
light comes on and the steam solenoid valve opens, allowing steam to flow into the compartment.
When steam flowing inside the compartment has raised
the interior temperature to 195°F, the contacts of a thermostatic switch automatically close, completing the circuit to the timer motor and starting the selected cooking
1-1
Required service, both preventive and corrective, is
explained in Section 6. Should repairs be required, a
network of authorized agencies is available to assist
with prompt service. A current Directory of Authorized
Service Agencies may be obtained by contacting:
Product Service Department
Market Forge
35 Garvey Street
Everett, Massachusetts 02149
Telephone (617) 387-4100
The model and serial numbers must be referenced
when corresponding with Market Forge. The data plate
containing the serial number pertaining to the equipment is located on the lower front trim of the cabinet.
2. INSTALLATION
2.1 ASSEMBLY
2.4 WATER CONNECTIONS
The Pressureless Cooker is factory-mounted on a cabinet base containing either a steam boiler or direct steam
connection controls for the cooker. The assembled unit is
shipped bolted to a skid, with cabinet feet in a separate
container. Steps required for assembly are as follows:
Before connecting water to this unit, have water supply
analyzed to make sure that hardness is no grater than
2.0 grains per gallon and pH level is within the range of
7.0–8.5. Water that fails to meet these standards should
be treated by the installation of a water conditioner.
1. Remove the four bolts that fasten the equipment
frame to the skid.
2. Install feet in threaded mounting locations of the
cabinet frame.
3. Mount the four pan support racks in brackets and
studs inside cooking compartments.
4. Attach panels to lower cabinet. Detailed instructions
are enclosed with the panels.
5. Attach the drip trough on studs located on the face
of the unit.
EQUIPMENT FAILURE CAUSED BY
INADEQUATE WATER QUALITY IS NOT
COVERED UNDER WARRANTY.
CAUTION
PVC or CPVC are not acceptable materials for
drains.
2.5 INSTALLATION CHECK-OUT
2.2 SETTING IN PLACE
Check-out procedures for the cooker mounted on
steam boilers of electric, gas, and steam coil utility or direct-connected steam are given in separate installation
instructions for each. Procedures for the cooker only are
included in Subsection 2.5.2. If the cooker fails to perform
as described, consult Table 5-1 of the Trouble-Shooting
Guide for corrective action. If difficulty arises with the
boiler, reference the separate service and parts manual for
that equipment.
Level the unit in final location by turning the adjustable
feet. Using the cabinet top as a reference, obtain level
adjustment left-to-right and front-to-back.
2.3 MECHANICAL CONNECTIONS
Since the Pressureless Cooker is interconnected at the
factory to the steam boiler or direct steam plumbing, no
field connections to the cooker are required. All electrical
and plumbing connections are routed to the steam boiler
cabinet through the 6-inch-high space between the floor
and the bottom edge of the cabinet frame. Connection
locations for the cooker mounted on steam boilers of electric, gas, and steam coil utility and direct-connected steam
are shown in separate installation instructions for each.
Before making this check-out, the operator must be thoroughly familiar with the operating procedures in Section 3
and with the function of each control described in Table 3-1.
Reference Figure 3-1 for identification of controls required
in the following procedures.
2.5.1
Initial Control Settings
Before beginning the start-up procedures for the cooker,
the instruction plate and service manual for the steam boiler
must be consulted and all start-up procedures completed
to supply 15 PSI steam to the steam inlet line for the
cooker.
2-1
2.
INSTALLATION (CONT.)
1. All steam boiler controls are in the operating mode
and 15 PSI steam is applied to the cooker inlet
plumbing.
2. Cooker timers for both compartments (Figure 3-1)
are in the OFF position.
3. Cooker compartments are empty of all information
materials, pan supports are mounted in place, and
doors are open.
2.5.2
Cooker Check-Out
The cooker check-out procedures are as follows:
1. With the doors open set timers to about the
“4-minute” position. Observe that indicator lights are
off and steam does not enter compartments.
2. Close cooker compartment doors. Observe that indicator lights turn on, and steam can be heard rushing into the compartment simultaneously with the
door closing.
3. Observe the boiler drain line for passage of steam
into the open floor drain. Correct steam condenser
operation is evidenced by presence of water flowing from the drain line.
4. Observe cooker operation for several minutes. Operation is correct if timer dials begin to rotate after a
short delay period required for preheating. After the
delay period plus the “4-minute” initial setting, the
timer dials will return to the “0-Minute” position, at
which a buzzer sounds. The buzzer is silenced by
turning the dial to the OFF position.
2.5.3
Shut-Down Procedure
No shut-down procedure is required for the Pressureless Cooker except to check that all timer dials (2) are in
the OFF position and the compartment doors are open.
Consult the steam boiler instruction plate and complete
the shut-down procedures for the boiler.
2.6 REVERSING THE DOORS
The Pressureless Steam Cooker has a reversible cooking compartment door. This section contains instructions
for reversing this door.
2-2
1.Turn off power to the unit.
2.Open the cooking compartment door
3.Remove the two screws that attach the top hinge to
the front of the unit.
4.Slide the door upwards, off the bottom hinge.
5.Remove the two screws that attach the bottom hinge
to the front of the units.
6. Remove the right and left side panels by unscrewing
the 1 screw on each panel and sliding the panel
down.
7. Remove the door interlock assembly by unscrewing
the two nuts that hold it in place (assembly is attached to the screws in the top right hinge mounting holes, see fig. 2-1).
8. Remove the four screws in the right side hinge mounting holes and install them in the left side hinge
mounting holes (where the hinges were originally
mounted).
9. Using the nuts removed in step #6, reinstall the door
interlock assembly onto the 2 screws in the lower
left hinge mounting holes (see fig. 2-1) with by
moving the assembly over the cooking cavity to
the other side of the unit. Rotate the door interlock assembly 180° for installation, so that the
switch is now facing up.
10. Reinstall the top hinge and screws into the right
lower hinge mounting holes. Rotate the hinge
180° for installation, so that the pin which the
door rides on is now facing up. The hinge must be
rotated because it will now function as the bottom
hinge. DO NOT COMPLETELY TIGHTEN THE
HINGE MOUNTING SCREWS YET. These will
be used later for adjusting the door.
11.Remove the door latch assembly from the face of
the unit. The 2 nuts mounting the door latch are
located behind the face of the unit and must be
accessed where the right side panel was removed.
12.Remove the two white hole plugs from the left door
latch mounting holes, and insert them into the right
door latch mounting holes (where the door latch
assembly was originally mounted).
13.Rotate the door latch assembly 180°, and install
into the left door latch mounting holes.
NOTE: Each stud on the latch assembly should
have a plastic washer, a spring, a plastic
washer and a Nyloc type nut,
2.
INSTALLATION (CONT.)
14. To adjust the tension of the door latch, tighten both
nuts down until the springs are fully compressed,
then back each nut off 1 1/2 turn.
15. Rotate the door 180° for mounting.
16. Slide the remaining hinge into the top door bearing.
17. Slide the door and hinge assembly down onto the
hinge which you have already mounted to the front
of the unit. Use the two screws to mount the top
hinge into the right upper hinge mounting holes.
DO NOT COMPLETELY TIGHTEN THE HINGE
MOUNTING SCREWS YET.
18. Slowly push the cooking compartment door closed
until it is latched.
19. The cooking compartment door can now be raised,
lowered, and/or rotated into position by bumping
it with the palm of your hand or by using a small
rubber mallet.
20. First, check the alignment at the front of the door by
making sure that the striker in the door is centered
with the latch mechanism on the front of the unit.
21. Square the door to the unit by raising or lowering the
hinge side of the door, keeping the latch centered
with the striker.
22. Visually inspect the door. Be sure that the door is
square to the unit, the striker is centered with the
latch, and the gasket is in contact with the entire
lip of the cooking compartment.
23. Gently open the cooking compartment door, taking
care not to move it out of position.
24. Tighten all 4 door hinge bracket mounting screws.
25. Close and visually inspect the door again, as described in step 22.
26. Reinstall the left and right side panels, using the
screws for each panel.
TOP RIGHT HINGE
MOUNTING HOLES
INTERLOCK ASSEMBLY
ORIGINAL POSITION
TOP LEFT HINGE
MOUNTING HOLES
DOOR LATCH ASSEMBLY
ORIGINAL POSITION
LEFT DOOR LATCH
MOUNTING HOLES
INTERLOCK ASSEMBLY
POSITION WHEN DOOR IS
REVERSED
LOWER LEFT HINGE
MOUNTING HOLES
LOWER RIGHT HINGE
MOUNTING HOLES
Figure 2-1. TYPICAL DOOR LAYOUT
2-3
3. OPERATION
3.1 OPERATING CONTROLS AND
INDICATORS
3. Turn off buzzer, which sounds to indicate cooking
is complete, by setting the Timer Dial (1) to OFF
position.
The controls and indicators required to operate the
Pressureless Steam Cooker are listed in Table 3-1,
together with a short functional description of each.
Figure 3-1 shows the physical location of each control
and indicator.
3.2.3
Before loading the cooker, be sure compartment is
hot. See Subsection 3.2.2 for preheating instructions.
1. Slide pans of food into cooking compartment pan
supports.
2. Close cooking compartment door.
3. Set timer cooking time:
a. CONSTANT STEAM—for continuous cooking
b. 60-MINUTE TIMER—for timed cooking.
3.2 OPERATING PROCEDURES
The ST-24 Pressureless Steam Cooker defrosts frozen foods and cooks fresh and defrosted foods. Each
cooking compartment permits selection of continuous
(constant steam) cooking or timed (0–60 minutes) cooking. Instructions for operation are included in this section. Consult Test Kitchen Bulletin for detailed cooking
information.
3.2.1
4. Set appropriate timer to the required cooking time
(see Test Kitchen Bulletin #59).
5. Turn off buzzer, which sounds to indicate cooking
is complete, by setting timer dial (1) to the OFF
position.
6. Open door sightly at first letting most of the steam
out of the compartment and then fully open the
door.
7. Unload by sliding pans of food from pan supports,
taking care to avoid hitting compartment opening.
Steam Source Operation
The Pressureless Cooker is supplied mounted on a
cabinet containing either a steam boiler or controls for
direct-connected steam. Manual controls are accessed
by opening the cabinet door. The start-up procedure
for the steam source is completed once before each
daily operating period of the cooker. (For steam boilers, see instruction plate.)
3.2.2
Cooking
3.2.4
Shut-Down Procedure
No shut-down procedure is required for the cooker
except to check that both timer dials (1) are in the OFF
position and that both compartment doors are open.
When all cooking has been completed for the day, the
steam source must be shut off. (For steam boilers, see
instruction plate.)
Preheating
Before each initial operation of the cooker, and at
any other time when the cooking compartment is cold,
a 1-minute preheating period is required. To preheat
the cooker, put steam source into operation and proceed as follows:
CAUTION
When the unit is not in use, leave the cooking
compartment door slightly ajar to prolong the
life of the door gasket.
1. Close cooking compartment door.
2. Set 60-Minute Timer Dial (1) to “1-minute” setting.
NOTE
Total elapsed preheating time equals the
timer setting plus a short delay period
needed to active a thermostatic switch included in the controls.
3-1
3.
OPERATION (CONT.)
3.3
Cleaning
After each period of daily operation (more frequently
as required to maintain cleanliness), the cooker should
be thoroughly cleaned by completing the following
steps:
1. Remove left- and right-side pan supports, baffles,
and drain screens by lifting up and off mounting
studs. Wash with a mild detergent. Rinse and set
aside for reassembly.
2. Wash cooking compartment interior using a mild
detergent and water. Rinse and dry thoroughly.
3. Replace pan supports, baffles, and drain screens
in compartment and leave door open.
3.4 DRAINAGE
3.4.1
Cooking Compartment Drainage
The bottom of the cooking compartment is angled
slightly toward the rear of the unit. This assures that
any condensate build-up or spills will be directed toward the drain hole, which is located at the rear bottom
center of the cooking compartment. Any liquid exiting
the cooking compartment runs down the cooking compartment drain tube and into the drain line.
3.4.2
Drip/Spill Trough Drainage
The ST-24 Pressureless Steam Cooker has a drip/
spill trough below the cooking compartment door. It will
catch any condensate gathering on the front of the unit
when the door is opened.
TABLE 3-1.
CONTROLS AND INDICATORS
(See Figure 3-1)
FIG.3-1 REF. DESCRIPTION
Figure 3-1. Controls and Indicators
FUNCTION
1
Timer/Constant Stream Controls Cooking up to 60 minutes or
uses constant operation.
2
Indicator Light (Red)
Indicates cooker is in operation.
3
Digitial Timer
Control Cooking up to 99 mins or constant
4
Mode Switch
Constant Steam / Timer
5
Compartment Switch
Top&Bottom Cavity OR Kettle/Btm Take-off
3-2
3.
OPERATION (CONT.)
TEST KITCHEN BULLETIN
Model ST-24 Pressureless Cooker
Facts On Parade
3.5 TEST KITCHEN BULLETIN
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
Frozen vegetables should always be cooked in perforated 12” x 20” x 21/2” (1/1 65mm) pans 71/2 lbs (34 kg)
maximum per pan.
Frozen entrees should be underlined with a perforated pan for best results. If they are defrosted first, the
heating time will be decreased.
Fresh foods may also be cooked in this unit. Vegetables and other foods where the stock is not to be retained
should be cooked in perforated 12” x 20” x 21/2” (1/1 65mm) pans for the most nutritious results.
There is a thermostatic time delay built into this unit which adapts the unit to the proper cooking time. This
means that the total time will usually be longer than the time setting.
There is a safety interlock switch on the door which shuts off the steam each time the door is opened if the unit
is in the cooking cycle.
Both compartments may be filled and timers set simultaneously.
Total cooking time will vary depending on the load, even though the timer setting is the same.
All foods, except cakes and pastry, can be cooked in a steam cooking unit.
Steam cooked meals have greater nutritional value since they retain most of their vitamins and minerals.
Because foods are cooked faster by the higher temperatures of steam cooking, they can be prepared closer
to serving time, insuring maximum freshness.
Steam cooked foods have a higher percent yield more portions per dollar spent.
Food may be served from the same pan in which it is steam cooked, thus reducing food breakage since there
is no extra handling or transferring of food from cooking pans to serving pans. It also reduces pot washing
tasks.
Some important advantages of steam cooking are labor saving, reduced operating costs, space saving, and
the lifting of heavy stock pots is eliminated.
Rice and spaghetti products, if thoroughly wet at the start of the cooking process, are very easily prepared.
Food such as potatoes, poultry, seafood, and some meats may be blanched in the steam cooker, thus reducing the total cooking time and grease absorption.
Fuel is used only when the steam cooking unit is in operation.
The steam cooker will loosen foods burned on pans making washing easier.
Solid pans are recommended when liquid is to be retained and perforated pans when the liquid is not to be
retained.
Eggs may be cooked out of the shell if they are to be chopped which eliminates peeling after steaming.
The steam cooker can be opened during the cooking period to add or remove items. If any time is lost, an
adjustment may be make on the timer.
Steam cooking information, including recommended pan size and type, weight per pan, cooking times and pan
yields are given on the following pages of this bulletin.
3-3
3.
OPERATION (CONT.)
The ST-24 Pressureless Cooker is a two compartment unit. Each compartment holds ten 12” x 20” x 21/2” or six
12” x 20” x 4” pans. This unit enables the cook to prepare foods close to the time of service. The cooking times
given are timer settings and should be set in a preheated compartment. There is a thermostatic time delay in each
compartment that adjusts the total time depending on the temperature and amount of the food. Therefore the total
time will be greater than the timer setting. At the end of the timer cooking cycle the buzzer will sound, steam will
stop flowing and the food can be removed.
FROZEN VEGETABLES
ITEM
Asparagus
Spears
Beans, Green
Regular
Beans, Green
French Cut
Approx. Number
Approx. Frozen Recommended
Cooked
Timer
12” x 20” (1/1) Number Settings in
Weight
Servings
Perforated Pan of Pans
Per Pan
Per Pan
Minutes
7 1/2 lbs. (3.4 kg)
2 1/2” (65mm)
10
12-15
30 3 oz. (85 g)
6 lbs. (2.7 kg)
2 1/2” (65mm)
10
10-15
25 3 oz. (85g)
6 lbs. (2.7 kg)
2 1/2” (65mm)
10
5-7
25 3 oz. (85 g)
7 1/2 lbs. (3.4 kg)
2 1/2” (65mm)
10
12-15
30 3 oz. (85 g)
6 lbs. (2.7 kg)
2 1/2” (65mm)
10
4-6
25 3 oz. (85 g)
7 1/2 lbs. (2.7 kg)
2 1/2” (65mm)
10
10-15
30 3 oz. (85 g)
Carrots
6 lbs. (2.7 kg)
2 1/2” (65mm)
10
10-15
25 3 oz. (85 g)
Cauliflower
6 lbs. (2.7 kg)
2 1/2” (65mm)
10
7-12
25 3 oz. (85 g)
Corn-Cut
7 1/2 lbs. (3.4 kg)
2 1/2” (65mm)
10
8-12
30 3 oz. (85 g)
Mixed Vegetables
7 1/2 lbs. (3.4 kg)
2 1/2” (65mm)
10
8-12
30 3 oz. (85 g)
Peas (Loose)
7 1/2 lbs. (3.4kg)
2 1/2” (65mm)
10
30 3 oz. (85 g)
Spinach
9 lbs. (4kg)
2 1/2” (65mm)
10
Squash
12 lbs. (5.4 kg)
2 1/2” (65mm)
10
3-5
Must be
defrosted
Must be
defrosted
Beans, Lima
Broccoli
Brussel
Sprouts
30 4 oz. (115 g)
50 3 oz. (85 g)
FROZEN PREPARED ENTREES
ITEM
Weight
Per Pan
Lobster Tails
6-8 oz. (170-255 g) 7-8 lbs. (3.2-3.6 kg)
Shrimp, C.D.P.
Shrimp
Green
Bulk Pack Frozen
Bulk Pack
Defrosted
Recommended
Approx. Number
Timer
12” x 20” (1/1) Number Settings in Cooked Servings
Perforated Pan of Pans Minutes
Per Pan
2 1/2” (65mm)
10
15-25
15 6 oz. (170 g)
16-20 lbs. (7-9 kg)
2 1/2” (65mm)
10
8-11
75 3 oz. (85g)
16-20 lbs. (7-9 kg)
2 1/2” (65mm)
10
11-15
50 3 oz. (85 g)
3 1/2-4 lbs. (1.6-1.8 kg)
2 1/2” (65mm)
10
35-45
10 6 oz. (170 g)
3 1/2-4 lbs. (1.6-1.8 kg)
2 1/2” (65mm)
10
25-35
10 6 oz. (170 g)
3.
OPERATION (CONT.)
PRESSURELESS STEAM COOKING TIMER SETTINGS AND PORTIONS
VEGETABLES
ITEM
Approx. Number
Cooked
Approx. Frozen Recommended
Timer
Number
12”
x
20”
(1/1)
Servings
Weight
Settings in
Perforated Pan of Pans
Per Pan
Per Pan
Minutes
Beans, Snap Green
6 lbs. (2.7 kg)
or Waxed
Beets (50 mm)
7 1/2 lbs. (3.4 kg)
2” Diameter
Broccoli 1/2-3/4”
6 lbs. (2.7 kg)
(12-20 mm) Stalks
Carrots
9 lbs. (4 kg)
Sliced
Cauliflower, Trimmed
1 1/2-2” (38-50 mm) 6 lbs. (2.7 kg)
Corn on Cob
1 doz.
Husked
Cabbage 1/4-1/6
5 lbs. (2.25 kg)
of Head, Cored
Onions, 2” (50 mm)
6 lbs. (2.7 kg)
Diameter
Peas, Shelled
Potatoes, French
Fry Cut
Potatoes, Regular
Cut, 3” (75 mm)
Spinach, Cleaned
Cut
Squash, Summer,
Sliced 1” thick (25 mm)
Squash, Winter
Peeled
Turnip,
Diced
2 1/2” (65mm)
10
18-22
25-30 3 oz. (85 g)
2 1/2” (65mm)
10
40-50
30-35 3 oz. (85g)
2 1/2” (65mm)
10
14-18
25-30 3 oz. (85 g)
2 1/2” (65mm)
10
18-21
35-40 3 oz. (85 g)
2 1/2” (65mm)
10
12-16
30-35 3 oz. (85 g)
2 1/2” (65mm)
10
10-15
12
2 1/2” (65mm)
10
14-18
15-20 4 oz. (115 g)
2 1/2” (65mm)
10
20-25
25-30 4 oz. (115 g)
5 lbs. (2.25 kg)
2 1/2” (65mm)
10
5-6
25-30 3 oz. (85 g)
10 lbs. (4.5 kg)
2 1/2” (65mm)
10
18-21
50 3 oz. (85 g)
10 lbs. (4.5 kg)
2 1/2” (65mm)
10
35-40
50 3 oz. (85 g)
3 lbs. (1.4 kg)
2 1/2” (65mm)
10
3-5
10-12 3 3/4 oz. (105 g)
7 lbs. (3.2 kg)
2 1/2” (65mm)
10
7-10
30-35 3 oz. (85 g)
9 lbs. (4 kg)
2 1/2” (65mm)
10
10-15
25-30 3 oz. (85 g)
5 lbs. (2.25 kg)
2 1/2” (65mm)
10
28-32
20-25 4 oz. (115 g)
VEGETABLES -Canned
ITEM
Canned
Vegetables
Weight
Per Pan
Recommended
12” x 20” (1/1)
Perforated Pan
7 lbs. (3.2 kg)
2 1/2” (65mm)
Timer
Approx. Number
Number Settings in Cooked Servings
of Pans
Minutes
Per Pan
10
5-10
25-30 3oz. (85 g)
3.
OPERATION (CONT.)
PRESSURELESS STEAM COOKING TIMER SETTINGS AND PORTIONS (continued
MEAT—POULTRY—FISH
ITEM
Approx. Frozen Recommended
Timer
Number
12”
x
20”
(1/1)
Weight
Settings in
Perforated Pan of Pans
Per Pan
Minutes
Approx. Number
Cooked
Servings
Per Pan
8 lbs (3.6 kg)
2 1/2” (65mm)
10
20-30
3 each
4” (100 mm)
10
45-50
2 each
4” (100 mm)
10
50-60
15-20 2 oz.
Protein (55 g)
25-30 2 oz.
Protein (55 g)
20-25 2 oz.
Protein (55 g)
Fish, Fillets
3 lbs (1.4 kg)
2 1/2” (65mm)
10
10-15
12-15 2 oz. (55 g)
Frankforts
Hamburgers
3 oz. (85 g)
Meatballs
1 oz. (30 g), size*
5 lbs (2.3 kg)
2 1/2” (65mm)
10
3-5
5 lbs (2.3 kg)
2 1/2” (65mm)
10
18-22
6 lbs (2.7 kg)
2 1/2” (65mm)
10
20-25
Meatloaf*
Pork Chops, 4 oz.
Loin Bone (115 g)
Sausage
1 1/2 oz. (45 g)
Turkey
On Carcass
Turkey
Off Carcass
15 lbs (6.8 kg)
2 1/2” (65mm)
10
40-50
6 lbs (2.7 kg)
2 1/2” (65mm)
10
25-30
35-40 2 oz. (55 g)
20-25 2 oz.
Protein (55 g)
20-25 2 oz
Protein (55 g)
50-60 2 oz.
Protein (55 g)
24 2 oz.
Protein (55 g)
6 lbs (2.7 kg)
2 1/2” (65mm)
10
18-21
20-22 lbs (9-10 kg)
2 1/2” (65mm)
1
2-2 1/2 hrs.
10-12 lbs (4.5-5 kg)
2 1/2” (65mm)
10
Chicken
Cut-up
Chicken, 4 lbs.
Whole
Fowl, 5 lbs. or more
Whole
18-20 2oz. (55 g)
50-60 2 oz.
Protein (55 g)
55-65 2 oz.
Protein (55 g)
1-1 1/4hrs.
* Raw weight for Meatballs and Meatloaf includes hamburg and extenders and yields 2 oz. (55 g) protein plus
extenders or 3 oz. (85 g) total portion.
MISCELLANEOUS
ITEM
Eggs
In Shell
Eggs
Out of Shell
Rice —
Bulletin 16
gives
direction
Spaghetti
Bulletin 13
gives
direction
Weight
Per Pan
Recommended
12” x 20” (1/1)
Perforated Pan
Approx. Number
Timer
Number Settings in Cooked Servings
of Pans Minutes
Per Pan
3 dozen
2 1/2” (65mm)
10
9-11
4 dozen
2 1/2” (65mm)
10
6-8
36
1 egg each
48
1 egg each
4 lbs. (1.8 kg)
2 1/2” (65mm)
10
18-22
60-65 3oz. (85 g)
3 lbs. (1.4 kg)
4” (100mm)
10
18-22
40-45 4oz. (115 g)
4.
PRINCIPLES OF OPERATION
4.1 GENERAL
The ST-24 Pressureless Steam Cooker consists of
two identical cooking compartments, one above the other,
in a single cabinet assembly. Each compartment is fitted with independent electrically controlled steam circuits
and spring-loaded, self-sealing doors with slam action
latches. Compartments can be used separately or simultaneously for either constant steam or 60-minute timing. The principles of operation in this section include an
explanation of steam, steam condensing, and electrical
circuits and their functioning.
4.2 PLUMBING CIRCUITS
The plumbing circuits consist of the piping, steam
solenoid valves, orifice, drain, and cold water condenser
required to provide controlled steam application to the
cooking compartments. A simplified diagram of these
circuits is shown in Figure 4-1.
NOTE
Steam inlet lines for compartments are equipped with
normally closed solenoid valves operated by the electrical control circuits. The inlet valves are opened whenever the compartment control circuit is activated by use
of the 60-minute timers.
4.2.1
A steam supply line is plumbed from the boiler output (or direct-connected steam control) to a 1/2-inch barb
fitting connected to the input sides of both steam inlet
solenoid valves. When a cooking compartment is not in
use, the valve for the compartment remains closed to
prevent steam from entering. During operation, the appropriate inlet solenoid valve is opened by activation of
the control circuit. Steam is projected onto the surface
of pans of food loaded into the compartment by an orifice located inside the compartment. Steam continues
to flow through the compartment in this manner until
the control circuit closes the solenoid valve.
4.2.2
Figure 4-1 is strictly a pictorial schematic diagram
and is not intended to show the actual configuration of the plumbing. All components are shown in
correct relationship with each other. However, the
diagram does not show their actual locations or
position within the cooker.
Steam Inlet Line
Steam Exhaust and Drain Lines
Perforated strainers at the drain line openings inside
each compartment allow only steam, condensation, and
liquid cooking drainage to enter. Prior to discharge into
the boiler drain system, steam is converted to water by
the cold water condensing systems for each compartment.
As shown in the diagram, steam inlet and exhaust
connections are connected at the factory directly into a
steam boiler or direct-connected steam plumbing enclosed within the base cabinet on which the cooker is
mounted. The boiler (or direct-connected steam control system) is equipped to supply constant, regulated
steam at 14–15 PSI. Steam exhaust, having been reduced to water by the cold water condenser, is directed
into the boiler (or direct-connected steam control) drain
system.
4-1
4.2.3
Steam Exhaust Condensing System
The steam condensing system consists of the identical, two-position, normally closed cold water solenoid
valves, with outlet sides connected into the exhaust
plumbing for each cooking compartment. A spray
nozzle directs cold water about the inside of the drain
lines to increase cold water contact with exhausted
steam. Valve inlet sides are connected remote from the
supply line of the steam boiler (or direct-connected
steam plumbing). The valves respond to a thermostatic
switch located inside the compartment. When the timer
starts the cold water solenoids will energize.
4.
PRINCIPLES OF OPERATION (CONT.)
Figure 4-1. Pictorial Diagram, Steam and Water Circuits (Model ST-24)
4.3 ELECTRICAL CIRCUITS
The electrical circuits of the cooker control the power
to activate timer motors and energize solenoid-operated valves and circuits, which in turn control application of steam to the cooking compartment and
condensation of steam from the exhaust line. The
cooker operates on 120V, 2 amp, 60Hz electrical service connected to all circuits from the circuits of the
steam boiler (or direct-connected steam controls) contained within the cabinet on which the cooker is
mounted. Power is supplied to the control circuit at all
times when the shut-off device (Circuit Breaker) for the
unit (installed by an certified Electrician) is in the ON
position.
4-2
4.
4.3.1
PRINCIPLES OF OPERATION (CONT.)
4.3.1.3
Control Circuit Components
The buzzer is an alarm device that operates by oscillation of a striker against the core of an electromagnet.
When the 60-minute timer dials reach the “0-Minute” position, the buzzer coil is energized to sound the buzzer.
Movement of the timer dial to the OFF position opens
the contact to the buzzer coil to shut it off.
A brief description of the electrical circuit elements
follows.
4.3.1.1
60 Minute Timer/Constant Steam
The timer contains a 120-volt AC synchronous motor that drives a timing dial through a gear reduction
and clutch mechanism. The timer dial is manually set
for any interval of operation from 0 to 60 minutes or
constant steam as read on the calibrated dial face. The
manual rotation of the dial moves the common element (1) of the timer switch from the neutral (OFF) position to contact (3), which connects with the steam inlet
solenoid valve operating circuit.
4.3.1.4
Door Interlock Switch
The interlock switch is a single-pole proximity switch
with normally open contacts. The switch is operated by
the proximity of a magnet within the door. When the
door is open, the switch contacts remain in the open
position. When the door is closed and securely latched
in place, the magnet is near the switch to close the contacts. Connected between the operating contact (3) of
the timers and the steam inlet solenoid valve, the door
switch acts as a protective device to interrupt valve operation unless the door is closed.
The cooker is placed into automatic operation with
the setting of the timer dial. Its timing cycle, however, is
automatically delayed by a thermostatic switch, which
assures operating temperature is achieved before the
timer motor begins to “time out.” When the timer motor
has operated for the preset duration, the common element is transferred to contact (4), returning the inlet solenoid valve to the closed position and energizing the
buzzer. Contact to the buzzer circuit remains closed
until the dial is manually turned to the OFF position,
returning the common element (1) of the timer switch
to the neutral position.
4.3.1.2
Buzzer
4.3.1.5
Thermostatic Switch
The thermostatically operated switch is a two-position, normally open switch mounted on the cooking
compartment. The switch functions to activate the cold
water solenoid valves of the steam condensing system
and to delay timer motor operation until the compartment temperature reaches 195°F, thus assuring that
cooking temperature exists throughout the timed duration.
Indicator Lights
An indicator light is included for both compartments.
The light remains on (red) at all times when the coinciding timer dial is set and the door interlock switch is
closed. The light turns off at the end of the timed cooking duration or when the set time has elapsed.
4.3.1.6 Digital Timers (Optional)
The timer controls the steam to the cavity by
either a constnat steam setting or a used defined timer
that will be programmed by the user into the timer
4.3.1.7 Kettle Switch (Optional)
The Kettle Switch will allow the user to set the
mode of the steam. The user can either set the switch
so that top and bottom cavity are in use at the same
time. Or the bottom cavity and a seperate direct connected kettle can be used at the same time.
4-3
5.
TROUBLE-SHOOTING
5.1 GENERAL
5.3 ELECTRICAL FAULT ISOLATION
The information in this section is intended to assist
both the operator and service personnel in locating
the general source of problems that may occur with
the cooker. Before following any of the procedures
given in this section, the operator should be thoroughly
familiar with the operating instructions and the function of all controls that are described in Section 3. If
the problem cannot be readily corrected, the operator
should contact the nearest Market Forge service
agency for assistance.
Correction of an electrical failure first requires isolation of the fault to a single circuit or component. In most
cases, the nature of the failure and its effect upon the
operation of the cooker will be sufficient to narrow it
down to one or more circuit elements. Table 5-2 is provided as a guide for isolating electrical faults.
5.4 ELECTRICAL TROUBLE-SHOOTING
PROCEDURES
Before performing the trouble-shooting procedures
in this section, the serviceman must be familiar with
the function of all controls as described in Section 3
as well as with the Principles of Operation described in
Section 4.
5.2 TROUBLE-SHOOTING GUIDES
A trouble-shooting guide for use by service personnel is given in Table 5-1.
TABLE 5-1
GENERAL TROUBLE-SHOOTING GUIDE
PROBLEM
1. INDICATOR LIGHT FAILS TO
LIGHT WITH TIMER SET.
2. STEAM FAILS TO ENTER
COOKING COMPARTMENT WITH
INDICATOR LIGHT ON.
PROBABLE CAUSE
REMEDY
a. Power to cooker off
Locate external circuit breaker for incoming
power and place in ON position.
b. Door interlock switch
contacts not closed
Shut cooker door to close switch contacts.
Check alignment of door with switch.
c. Door interlock switch faulty
Replace switch. See Subsection 5.4.5.
d. Indicator light burned out
Replace light.
e. Faulty timer contacts
Replace timer. See Subsection 5.4.4.
f. Faulty wiring
Inspect condition of wire and tightness of all
connections. Correct as needed.
a. Faulty steam solenoid
valve
Replace valve. See Subsection 5.4.6.
b. Faulty wiring
Inspect condition of wire and tightness of all
connections. Correct as needed.
5-1
5.
TROUBLE-SHOOTING (CONT.)
TABLE 5-1 (cont’d.)
PROBLEM
3. STEAM ENTERS COMPARTMENT
CONTINUOUSLY. TIMER DIAL
NOT TURNING.
4. STEAM CONTINUES TO FLOW
INTO COMPARTMENT AND/OR
BUZZER FAILS TO SOUND AT
END OF TIMER SETTING.
5. STEAM FLOWS CONTINUOUSLY
FROM BOILER (OR DIRECTCONNECTED STEAM CONTROL)
DRAIN LINE WITH COOKER IN
OPERATION.
PROBABLE CAUSE
a. Constant steam position
Move knob to timing location.
b. Faulty thermostatic switch
Replace switch. See Subsection 5.4.8.
c. Faulty timer motor
Replace timer. See Subsections 5.4.4
d. Faulty steam solenoid
valve
Replace valve. See Subsection 5.4.6.
e. Faulty wiring
Inspect condition of wire and tightness of all
connections. Correct as needed.
a. Timer contacts faulty
Replace timer. See Subsection 5.4.4.
b. Buzzer faulty
Replace buzzer. See Subsection 5.4.9.
c. Faulty wiring
Inspect condition of wire and tightness of all
connections. Correct as needed.
a. Cold water not connected
Turn on external shut off valve.
b. Faulty thermostat
Replace thermostat. See Subsection 5.4.8.
c. Faulty cold water solenoid
Replace valve.
d. Faulty wiring
Inspect condition of wire and tightness of all
connections. Correct as needed.
5.4.2
The electrical trouble-shooting procedures that follow
require access to components and terminals of the electrical control panel shown in Figure 7-3. Electrical controls are reached by removing screws that fasten the
control panel to the frame. The panel may be pulled forward for testing while interconnected to the cooker circuits or disconnected at the pin connection for complete
removal and repair.
Electrical Inspection
The first step in any electrical trouble-shooting procedure is a thorough physical inspection of all wiring connections. To access electrical components, remove the
control panel as explained in Subsection 6.3.4.
5. TROUBLE-
5.4.1
REMEDY
WARNING
Before removing control panel or checking connections and wiring, be sure that the circuit breaker for
incoming power is OFF. When power is supplied,
all exposed terminals of the control panel carry
120 volts.
SHOOTING
Incoming Power
Before trouble-shooting any of the electrical parts or
assemblies, verify that power is being supplied to the
cooker. Incoming power is connected at the boiler (or
direct-connected steam) control box located in the base
cabinet. With power connected to the cooker, an AC voltmeter is used to measure 120 volts across L1 and L2. If
120 volts is present, and the cooker will not operate, the
fault lies within the electrical circuits of the cooker.
Check all wiring connections by hand to assure that
both ends of all connection points are tightly secured.
Use a screwdriver to tighten connection points. If necessary, visually inspect all quick-disconnect terminals for
evidence of corrosion. Terminals in this condition should
be separated, cleaned with emery cloth until shiny, and
tightly reconnected.
5-2
5.
TROUBLE-SHOOTING (CONT.)
TABLE 5-2
ELECTRICAL FAULT ISOLATION GUIDE
FAILURE
FAULT LOCATION
a. Incoming power
b. Timer
c. Door interlock switch
1. Will not operate in either CONSTANT STEAM or 60-MINUTE
TIMER positions.
d. Wiring
2. Operating in CONSTANT STEAM position but not in 60-MINUTE
TIMER position.
a. 60-minute timer
b. Wiring
3. Operates in 60-MINUTE TIMER position but not in CONSTANT
STEAM position.
a. Timer
b. Wiring
4. Steam solenoid valve fails to open with indicator light on.
a. Solenoid valve coil
b. Wiring
5. Indicator light off with steam solenoid valve open.
a. Indicator light
b. Wiring
6. With indicator light on and steam solenoid valve open, timer dial
fails to turn.
a.
b.
c.
d.
7. Buzzer fails to sound at end of 60-MINUTE TIMER mode.
a. 60-minute timer contacts
b. Buzzer
c. Wiring
8. Steam flows continuously from boiler drain line.
a. Thermostatic switch
b. Cold water solenoid valve
c. Wiring
5.4.4
5.4.4.1
60-Minute Timer
Timer Contacts
6. Rotate timer dial to “0-Minute” position (an audible
click indicates correct position). If zero ohm reading cannot be obtained, the timer is defective and
must be replaced.
7. Remove ohmmeter and replace all five leads on
timer terminals as shown in Figure 5-1.
Defective timer contacts will result in failure of either
cooker compartment to operate. When this occurs, remove the control panel (see Subsection 6.3.4), and proceed as follows:
1. Turn off power to the cooker at external circuit
breaker.
2. Disconnect all five wires from timer terminals (see
Figure 5-1).
3. Connect an ohmmeter between terminals 1 and 3.
4. Rotate timer dial beyond the “0-Minute” point (any
setting) to obtain a reading of zero ohms on the
ohmmeter. If zero ohm reading cannot be obtained,
timer contacts are defective and the timer must be
replaced.
5. Move ohmmeter leads to terminals 1 and 4.
Compartment thermostatic switch
Constant steam position
Timer motor
Wiring
5.4.4.2
Timer Motor
A defective timer motor will cause continuous operation in the TIME mode, with the timer dial failing to return to the “0-Minute” position. Since thermostatic switch
failure can cause the same symptom, fault must first be
isolated to the timer by testing the thermostat (see Subsection 5.4.8).
To confirm timer motor condition, proceed as follows:
5-3
TROUBLE-SHOOTING (CONT.)
FRONT CONTROL PANEL
5.
Figure 5-1. Wiring Diagram Mechanical Controls, Model ST-24
5-4
TROUBLE-SHOOTING (CONT.)
FRONT CONTROL PANEL
5.
Figure 5-2. Wiring Diagram Digitial Controls, Model ST-24
5-5
5.
TROUBLE-SHOOTING (CONT.)
5.4.7
1. Carefully check motor wire leads and tighten loose
connections.
If the cooker compartment functions correctly, with
the single exception that the indicator light fails to light
during operation, the fault is a defective indicator light.
A “burned out” or defective light is verified by using an
AC volt-meter at the leads, with input power on the selector switch in the correct position for that timer, the
timer set, and the door latches closed. If 120 volts is
present, the fault is in the indicator light and requires
replacement. If 120 volts is not present, the fault is in
the wiring or control components (selector switch, timer,
or door switch).
WARNING
Use care while working with control panel.
Terminals carry 120 volts.
2. Turn on power to the cooker.
3. Set timer dial (any setting beyond “0-Minute”). If
operation is correct, the motor will turn the dial
toward “0-Minute.” If the motor fails to operate, it
is defective and the entire timer must be replaced.
4. Shut off power to the cooker.
5.4.8
5.4.5
Door Interlock Switch
Malfunction of the cooker door interlock switch prevents timer indicator lights from turning on and steam
solenoid from opening when the timer dial is set. If
steam does not enter the compartment and the indicator light fails to turn on with the door latch securely engaged, the fault may be in the door interlock switch.
Proceed as follows:
Cooking Compartment Thermostatic
Switch
A thermostatic switch included in the circuit for the
timer motor delays timer operation until steam flowing
into the compartment satisfies the temperature-actuated switch device. If a timer motor fails to operate within
about one minute after the indicator light comes on (with
cooker compartment empty), the cause may be a defective thermostatic switch. To test the switch, proceed
as follows:
1. Turn off power to the cooker.
2. Disconnect wires to the door switch terminals (see
Figure 5-1).
3. Connect an ohmmeter between the terminals of
the switch.
4. Actuate the switch by closing the cooking compartment door. If a zero reading cannot be obtained, the switch is defective and must be
replaced.
5. Remove the ohmmeter and replace the leads on
switch terminals (see Figure 5-1).
5.4.6
Indicator Lights
1. Disconnect the two wires connected to the thermostatic switch terminals.
2. Connect an ohmmeter between the two terminals
of the switch.
3. Place the cooker into operation and observe ohmmeter dial. Within one minute of operation, the
switch contacts close automatically to register a
zero ohm reading on the dial. If a zero ohm reading is not obtained, the switch is defective.
4. Shut off cooker, disconnect ohmmeter leads, and
replace wires on switch terminals.
Steam Solenoid Valves
5.4.9
When either inlet solenoid valve fails to operate, the
fault may be a defective coil. A defective coil is found
using an AC volt-meter to check the voltage at the coil
wire terminals, with the cooker compartment operating
in either CONSTANT STEAM or 60-MINUTE TIMER
mode. If voltage of 120 volts is present and the coil fails
to open the valves, the fault is in the valve coil. Defective valve coils are not separately replaceable, requiring complete valve replacement.
Buzzer
If the buzzer does not sound at the termination of the
operator-selected timer setting (timer dial returned to
“0-Minute” position), the fault may be a defective buzzer.
Buzzer operation is verified using an AC volt-meter at
buzzer coil connections with input power on and selector switch and coinciding timer dial set at the “0-Minute”
position. If voltage is 120 volts, the fault is in the buzzer,
which must be replaced. If 120 volts is not present, the
fault is in the wiring or control components (timer or selector switch).
5-6
5.
5.4.10
TROUBLE-SHOOTING (CONT.)
Cold Water Condenser Circuit
5.4.11
If during cooker operation steam exits from the drain
line opening (located in lower boiler compartment) and
the condensing system fails to operate, as evidenced by
repeated discharge of water from the drain line, the condensing circuit is malfunctioning. The failure can be
caused by a defective condenser thermostat or cold
water solenoid coil, or by wiring failure. To test condenser
thermostat, refer to Subsection 5.4.8.
Wiring
All of the electrical components of the cooker (timers,
indicator lights, etc.) are connected to each other by wiring shown in Figure 5-1. If all of the electrical components are operating correctly (and the incoming power
has been checked), but the cooker fails to operate, the
fault lies in the wiring.
If the condenser thermostat functions correctly, but
either of the cold water solenoid valves fails to operate,
the cause might be a faulty valve coil. A defective coil is
found using an AC volt-meter to check the voltage at the
coil wire terminals with the cooker compartment in operation. If voltage of 120 volts is present and the valve
fails to open, the fault is in the valve coil. Defective valve
coils are separately replaceable.
Figure 5-1 is a diagram that shows all terminals and
interconnections within the electrical circuits. All numbered terminals are identified and all leads numbercoded as shown. Connections can be easily removed.
Figure 5-2 shows the same information schematically
and is an aid in isolating circuits for testing.
5-7
Using an ohmmeter, wiring continuity between the
connections shown on the wiring diagram (Figure 5-1) is
readily verified. This is best done in stages, removing
only those wires required for each continuity check. As
each lead is replaced, it should be checked for evidence
of corrosion, and cleaned if necessary. All leads must
be tightly attached so as to provide a good electrical
connection.
5.
TROUBLE-SHOOTING (CONT.)
PLUS TWENTY-FOUR
(2) COMPARTMENT
TOP
BOTTOM
Figure 5-3. Ladder Diagram, Model ST-24
5-8
6.
MAINTENANCE
6.1 GENERAL
6.2.1
Cooking Compartment Cleaning
This section contains both preventive and corrective
maintenance information. Preventive maintenance may
be performed by maintenance personnel at the establishment in which the cooker is installed. It is recommended that user personnel never attempt to make
repairs or replacements to the equipment without the
assistance of authorized service. Assistance in service
methods or a current Directory of Authorized Agencies
may be obtained from Market Forge (see Subsection 1.3).
A daily cleaning of the cooking compartments and pan
supports is required. See Subsection 3.3 for details.
6.3 REPAIR AND REPLACEMENT
Section 7 of this manual contains a listing of all replaceable parts and associated exploded views of the
ST-24 Cooker. In most cases, disassembly procedures
will be obvious from the exploded views. Instructions follow for procedures that are not readily apparent.
6.2 PREVENTIVE MAINTENANCE
6.3.1
A good preventive maintenance program begins with
the daily cleaning procedure described in Subsection 3.3. Additional preventive maintenance operations
are presented in this section. In establishments that
employ full-time maintenance personnel, the tasks described can be assigned to them. For other installations,
tasks requiring mechanical or electrical experience
should be performed by an authorized service agency.
Door Latch Tension Adjustment
CAUTION
SHUT OFF MAIN ELECTRICAL
POWER TO UNIT.
Procedure:
1. Open the cooking compartment door.
2. Remove the control panel by removing the eight
mounting screws and disconnecting the wire plug
and restraining wire.
3. Tighten both nuts down until the springs are fully
compressed.
4. Back each nut off 1/2 turn.
5. Remount the control panel, reconnecting wire plug
and restraining wire.
The following paragraphs set forth minimum preventive maintenance procedures that must be completed
periodically to assure continued trouble-free operation
of the cooker.
CAUTION
Under no circumstances should hardware (or
parts) be replaced with a different length, size, or
type other than as specified in the parts list. The
hardware used in the cooker has been selected
or designed specifically for its application, and the
use of other hardware may damage the equipment and will void any warranty.
6-1
6.
6.3.2
MAINTENANCE (CONT.)
Procedure—To Adjust Gasket to Unit:
Door Handle Tension Adjustment
Procedure:
1. Open the cooking compartment door.
2. Remove the six screws and washers from the top
edge and bottom edge of the door.
3. Remove the inner door gasket mounting plate assembly from the outer door. Do not disassemble
these three components—remove them as an assembly.
4. Tighten both nuts down until the springs on the outer
door are fully compressed.
5. Back each nut off 1/2 turn.
6. Remount the inner door gasket mounting plate assembly by assembling the six screws and washers.
6.3.3
Door Gasket Replacement
The cooking compartment door gaskets are made of a
silicone-type rubber material that is very durable but subject to wear during normal operation. Should the gasket
leak, readjust the door gasket to the unit or replace it.
Procedure—Replace Gasket:
1. Open the cooking compartment door.
2. Remove the six screws on the outside of the door,
and remove the inner door assembly.
2. Remove the eight nuts from the door gasket mounting plate on the inside of the inner door assembly.
3. Remove the door gasket mounting plate and the door
gasket.
4. Install the new door gasket (see Figure 7-2 for part
number) to the mounting plate.
5. Reassemble the mounting plate with gasket to the
inside of the inner door assembly using the eight
nuts.
6. Reassemble the inner door assembly using the six
screws on the outside of the door.
To prevent steam leaks around the door, adjust the
gasket tension to cavity. Adjust the gasket by loosening
the six screws on top and bottom of door, move inner
door plate in or out, left side or right side, and tighten the
six screws.
6.3.4
Exterior Panel Removal
WARNING
To prevent hazard in servicing the cooker, be
certain that the steam supply boiler is shut
down, the cold water shut-off valve is closed,
and the electrical disconnect circuit breaker
for the cooker/boiler unit is off before removing side panels.
Access to all internal plumbing and electrical assemblies is from the right side and right front. The left-side
panel is removed by removing the bottom screw and
pushing up on the panel until the lower lip disengages
the frame. The panel is shown as item #25 in Figure 7-1.
The electric control panel, shown in Figure 7-3, may
also be removed as a unit by removing screws and pulling the panel forward. Removal of the control panel is
completed by unplugging interconnecting wiring at the
pin housing.
6.3.5 Steam and Water Solenoid Valve
Replacement
Replacements for the 1/2-inch steam solenoid valves
and the 1/4-inch water valves are available as complete
units from Market Forge Authorized Service Agencies.
It is necessary to replace an entire steam valve when
the coil is faulty or the diaphragm ruptures. Replacement coils are available for the water valves. The valves
are accessed as explained in Subsection 6.3.4.
NOTE
Remember that the lip on the door gasket
mounting plate must fit into the channel on the
inside edge of the gasket to insure a proper
seal.
6-2
7.
ILLUSTRATED PARTS LIST
7.3 INDEX OF ILLUSTRATED PARTS LIST
7.1 GENERAL
FIGURE
This section contains a complete listing of all replaceable parts of the ST-24. For the purpose of parts identification, the unit is broken down into functional assemblies,
and each assembly is shown in an exploded view that is
keyed to the accompanying parts list. Each parts list
contains the figure index number, the Market Forge part
number, and an abbreviated description.
7.2 ORDERING INFORMATION
Orders for repair parts should be directed to the nearest authorized parts distributor. For a current Market
Forge Authorized Parts Distributor List, contact:
Product Service Department
Market Forge
35 Garvey Street
Everett, Massachusetts 02149
Telephone: (617) 387-4100
All orders should contain the Market forge part
number(s), the part description(s), and the model and
serial number of the cooker for which the part or parts
are ordered.
7-1
PART
PAGE
7-1
Cabinet Assembly
7-2
7-2
Door Assembly
7-3
7-3
Control Panel Assembly 7-4
7-4
Condensor Assembly
7-5
7.
ILLUSTRATED PARTS LIST (CONT.)
ITEM NO.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
PART NO.
08-6308
08-4912
10-2793
98-1643
08-6538
98-1643
08-6538
91-6491
91-7639
91-7318
10-9174
10-9175
91-6940
91-6475
91-6476
91-7334
91-7385
91-5621
91-6492
08-4600
98-1637
91-7684
98-1605
91-7699
10-4586
10-8105
10-3343
10-1956
10-2571
08-1204
10-2184
91-7569
91-7327
98-1632
98-1631
08-7959
08-7960
98-1638
98-1639
98-1640
08-2702
91-7690
DESCRIPTION
QTY.
REED SWITCH
2
ASSY, PLUMBING DRAIN
2
POST, REAR
2
COUPLER, 1/2"NPT X 5/8"ID BARB
4
ELBOW, 90, 1/2" IPS
4
BRACKET, REAR FRAME SUPPORT
1
CHECK VALVE 3/8 OD BLACK
2
GROMMET, SILICONE, RED
2
BRACKET, CAVITY SUPPORT
1
WELD ASSY, TOP
1
RELAY, TUBE
4
RELAY, BASE
4
BRACKET, RELAY
2
HINGE, ASSY TOP
2
HINGE, ASSY BOTTOM
2
TROUGH, DRIP, ST-20
1
ASSY, DOOR, ST-20
2
ASSY, JET PIPE
4
LATCH, DOOR
2
SPRING, COMPRESSION
4
MECHANICAL CNTRL PANEL W/SWITCH
1
STRAINER, CAVITY
2
WELD ASSY, MIDDLE RACK
2
RACK SIDE
4
NUT, 1/2" IPS, S.S. W/TEFLON
6
THERMOSTAT, SNAP DISC, PROBE TYPE
2
NUT, BRASS, 1/2" IPS
2
SCREW, TAPTIGHT, 8-32 X 3/8"
20
NUT, LOCK, 8-32
17
PLUG, HOLE WHITE
4
SCREW, HEX HEAD, 10-32, 3/4" LG
8
PANEL, SIDE
2
PANEL, REAR
1
INSULATION, FRONT
1
INSULATION, REAR
1
TUBING, NORPRENE 3/8" I.D.
AS MEASURED
TUBING, NORPRENE 5/8" I.D.
AS MEASURED
MECHANICAL CNTRL PANEL W/O SWITCH
1
DIGITIAL CNTRL PANEL W/ SWITCH
1
DIGITIAL CNTRL PANEL W/O SWITCH
1
BUSHING, DOOR, WHITE
4
BRACKET, REED SWITCH
2
7-2
7.
ILLUSTRATED PARTS LIST (CONT.)
Figure 7-1.
Cabinet Assembly
7-3
7.
ILLUSTRATED PARTS LIST (CONT.)
Figure 7-2.
ITEM NO.
1
2
3
4
5
6
7
8
9
PART NO.
91-7386
91-7387
91-7388
91-7389
91-5745
09-1608
08-5027
91-5901
08-4600
Door Assembly
DESCRIPTION
OUTER DOOR
INNER DOOR
GASKET RETAINING PLATE
DOOR GASKET
DOOR HANDLE
STRIKER
MAGNET
MAGNET BRACKET
COMPRESSION SPRING
7-4
QTY.
1
1
1
1
1
1
1
1
2
7.
ILLUSTRATED PARTS LIST (CONT.)
Figure 7-3.
ITEM NO.
1
2
3
4
5
6
7
8
PART NO.
98-1616
98-1612
08-6464
08-6541
91-6471
10-7395
08-3826
10-5052
Control Panel Assembly
DESCRIPTION
CONTROL PANEL
ARTWORK, CONTROL PANEL
60 MIN. TIMER
TERMINAL STRIP
BRACKET, TERMINAL STRIP
BUZZER
KNOB, TIMER
LIGHT, RED
7-5
QTY.
1
1
2
2
2
2
2
2
7.
ILLUSTRATED PARTS LIST (CONT.)
Figure 7-4. Condenser Assembly
ITEM NO.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
PART NO.
10-5859
08-4892
10-2885
10-2849
98-1477
08-6581
10-3739
98-1630
10-1055
10-3644
08-7525
08-6498
08-4912
08-7962
98-1477
DESCRIPTION
VALVE, STEAM SOLENOID
COUPLER, BRS 3/8ODX1/2THRD NPT
UNION, FEMALE 1/2 IPS
NIPPLE, CLOSE 1/2" NPT BRS
COUPLERBRS,BARB 3/8"X3/8" NPT
TEE, MALE 1/2" NPTX FEML 1/2" BRANCH
1/2"X 3/8 REDUCING BUSHING
WELDMENT, COLDH20/STEAM VALVE
TEE, 3/8" ALL AROUND
PLUG, SQ HEAD 3/8"IPS BRASS
NIPPLE, CLOSE 3/8" NPT BRASS
VALVE, 3/8" NPT, COLDW COND
COUPLER, BARB 5/8"ODX1/2" IPS
COUPLER, BARB 5/8"ODX3/8"THD
COUPLER, BRS BRARB,3/8"X3/8" THD NPT
7-6
QTY.
1
2
1
2
1
1
1
1
1
1
2
1
1
1
1
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