Market forge industries Plus-twelve st-12 Instruction manual

35 Garvey Street lEverett lMA l02149

Tel: (617) 387-4100 lFax: (617) 387-4456 lFax: (Outside MA) 1-800-227-2659

E-Mail: custser[email protected] lWebsite: http://www.mfii.com

INSTALLATION, OPERATION & MAINTENANCE MANUAL

Form Number: S-4475 Rev: A 06/03 Printed in U.S.A.

PLUS-TWELVETM

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: mST-12 COVERING:

mInstallation

mOperation

mService & Parts

TABLE OF CONTENTS

PARAGRAPH

SECTION 1 INTRODUCTION

1.1Description ............................................

1.2Basic Functioning .................................

1.3Service ..................................................

SECTION 2 INSTALLATION

2.1Assembly ..............................................

2.2Setting in Place .....................................

2.3Mechanical Connections ......................

2.4W ater Connections ...............................

2.5Installation Check-Out ..........................

2.5.1Initial Control Settings ...........................

2.5.2Cooker Check-Out ................................

2.5.3Shut-Down Procedure ..........................

2.6Reversing the Doors .............................

SECTION 3 OPERATION

3.1Operating Controls & Indicators ...........

3.2Operating Procedures ..........................

3.2.1Steam Source Operation ......................

3.2.2Preheating ............................................

3.2.3Cooking ................................................

3.2.4Shut-Down Procedure ..........................

3.3Cleaning ...............................................

3.4Drainage ...............................................

3.4.1Cooking Compartment Drainage ..........

3.4.2Drip/Spill Trough Drainage ...................

3.5T est Kitchen Bulletin .............................

SECTION 4 PRINCIPLES OF OPERATION

4.1General .................................................

4.2Plumbing Circuits ..................................

4.2.1Steam Inlet Line ....................................

4.2.2Steam Exhaust & Drain Lines ...............

4.2.3Steam Exhaust Condensing System ....

4.3Electrica Circuits ...................................

4.3.1Control Circuit Components .................

4.3.1.160 MinuteTimer ....................................

4.3.1.2Indicator Lights .....................................

4.3.1.3Buzzer ..................................................

4.3.1.4Door Interlock Switch ............................

4.3.1.5Thermostatic Switch .............................

SECTION 5 TROUBLE-SHOOTING

5.1General .................................................

5.2T rouble-Shooting ..................................

5.3Electrical Fault Isolation ........................

5.4Elec Trouble-Shooting Procedures .......

5.4.1Incoming Power ....................................

5.4.2Electrical Inspection ..............................

5.4.360 Minute Timer ....................................

5.4.3.1Timer Contacts .....................................

5.4.3.2Timer Motor ..........................................

5.4.4Door Interlock Switch ............................

5.4.5Steam Solenoid V alves .........................

5.4.6Indicator Lights .....................................

5.4.7Cooking Compartment Thermostat

Switch ...................................................

PARAGRAPH

5.4.8Buzzer ..................................................

5.4.9Cold W ater Condener Circuit ................

5.4.10Wiring ...................................................

SECTION 6 MAINTENANCE

6.1General .................................................

6.2Preventive Maintenance .......................

6.2.1Cooking Compartment Cleaning ..........

6.3Repair & Replacement .........................

6.3.1Door Latch Tension Adjustment ............

6.3.2Door Handle Tension Adjustment .........

6.3.3Door Gasket Replacement ...................

6.3.4Exterior Panel Removal ........................

6.3.5Steam & W ater Solenoid Valve

Replacement ........................................

SECTION 7 ILLUSTRATED PARTS LIST

7.1General .................................................

7.2Ordering Information .............................

7.3Index of Illustrated Parts List ................

7.4Illustrated Parts List ..............................

LIST OF TABLES

TABLE

SECTION 3 OPERATION

3-1Controls & Indicators ............................

SECTION 5 TROUBLE-SHOOTING

5-1General Trouble-Shooting Guide ..........

5-2Electrically Fault Isolation Guide ..........

LIST OF ILLUSTRATIONS

FIGURE

SECTION 2 INSTALLATION

2-1T ypical Door Layout ..............................

SECTION 3 OPERATION

3-1Controls & Indicators ............................

SECTION 4 PRINCIPLES OF OPERATION

4-1Pictorial Diagram -

Steam & W ater Circuits ........................

SECTION 5 TROUBLE-SHOOTING

5-1Wiring Diagram, ST -12 .........................

5-2Schematic Diagram, ST -12 ...................

SECTION 7 ILLUSTRATED PARTS LIST

7-1Cabinet Assembly .................................

7-2Door Assembly .....................................

7-3Control Panel Assembly .......................

7-4Condenser Assembly ............................

PAGE

1-1

2-1

2-2

3-1

3-2

4-1

4-2

4-3

5-1

5-2

5-3

5-6

PAGE

5-6

5-7

6-1

6-2

7-1

7-2/7-6



3-3

5-1

5-2



2-3

3-2

4-2

5-4

5-7

7-3

7-4

7-5

7-6

1-1

SECTION 1 INTRODUCTION

This service and parts manual contains general information, installation instructions, principles of operation, trouble-shooting,

and maintenance information for Market Forge ST-12 Pressureless Steam Cooker. 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-12 is a pressureless steam cooker consisting of a

controlled compartment enclosed in a single cabinet. The

compartment is equipped with a separate three-piece door

with inner gasket plate isolated from the exterior surface.

The door latch design ensures positive sealing of the inner

door. Steam delivery and steam-condensing circuits are

both electrically controlled. The operating controls are

displayed on a single front-mounted panel that includes a

timer with an indicator light for the selection of constant

steam or 60-minute-long duration cooking.

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.

1.2 Basic Functioning

The Model ST-12 compartment is equipped with 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

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.

When steam and condensate is emitted from the

compartment it is directed through a drain screen inside

the compartment into the cooker drain line. A cold water

solenoid valve connected into the compartment drain line

is automatically actuated by a thermostatic switch in the

cooking compartment drain line to condense the steam to

water prior to discharge into the drain.

1.3 Service

Required service, both preventive and corrective, is

explained in Section 6. Should repairs be required, a

network of authorized service 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 Industries Inc.

35 Garvey Street lEverett lMA l02149

Tel: (617) 387-4100 lFax: (617) 387-4456

Fax: (Outside MA) 1-800-227-2659

E-Mail: [email protected] lWebsite: http://www.mfii.com

The model and serial number must be referenced when

corresponding with Market Forge service personnel. The

data plate containing the serial number pertaining to the

equipment is located on the top front trim of the cabinet

base and also on the top panel of the steamer.

2-1

SECTION 2 INSTALLATION

2.1 Assembly

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:

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 two pan support racks in brackets and studs

inside cooking compartment.

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.

2.2 Setting in Place

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.

2.4 Water Connections

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.

2.5 Installation Check-Out

Check-out procedures for the cooker mounted on steam

boilers of electric, gas, and steam coil 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.

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.

1. All steam boiler controls are in the operating mode and

15 PSI steam is applied to the cooker inlet plumbing.

2. Cooker timer for the compartment (Figure 3-1) is in the

OFF position.

3. Cooker compartment is empty of all information

materials, pan supports are mounted in place, and door

is open.

2.5.2 Cooker Check-Out

The cooker check-out procedures are as follows:

1. With the door open set timer to about the “4-minute”

position. Observe that indicator light is off and steam

does not enter compartment.

2. Close cooker compartment door. Observe that indicator

light turns 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. Opera-

tion 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.

EQUIPMENT FAILURE CAUSED BY INADEQUATE

WATER QUALITY IS NOT COVERED UNDER

WARRANTY!

CAUTION

PVC or CPVC are not acceptable materials for drains.

2-2

SECTION 2 INSTALLATION

2.5.3 Shut-Down Procedure

No shut-down procedure is required for the Pressureless

Cooker except to check that the timer dial is in the OFF

position and the compartment door 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.

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

installa- tion, 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.

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.

NOTE:

Each stud on the latch assembly should have a plastic

washer, a spring, a plastic washer and a Nyloc type nut.

2-3

SECTION 2 INSTALLATION

TOP LEFT HINGE

MOUNTING HOLES

LEFT DOOR LATCH

MOUNTING HOLES

INTERLOCK ASSEMBLY

POSITION WHEN DOOR IS

REVERSED

LOWER LEFT HINGE

MOUNTING HOLES

TOP RIGHT HINGE

MOUNTING HOLES

INTERLOCK ASSEMBLY

ORIGINAL POSITION

DOOR LATCH ASSEMBLY

ORIGINAL POSITION

LOWER RIGHT HINGE

MOUNTING HOLES

Figure 2-1 Typical Door Layout

3-1

SECTION 3 OPERATION

3.1 Operating Controls and Indicators

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 Operating Procedures

The ST-12 Pressureless Steam Cooker defrosts frozen

foods and cooks fresh and defrosted foods. The 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 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 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:

1. Close cooking compartment door.

2. Set 60-Minute Timer Dial (1) to “4-minute” setting.

3. Turn off buzzer, which sounds to indicate cooking is

complete, by setting the Timer Dial (1) to OFF position.

3.2.3 Cooking

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.

4. Set appropriate timer to the required cooking time (see

pages 3.3 to 3.6).

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.

3.2.4 Shut-Down Procedure

No shut-down procedure is required for the cooker except

to check the timer dial (1) are in the OFF position and that

the compartment door is open. When all cooking has been

completed for the day, the steam source must be shut off.

(For steam boilers, see instruction plate.)

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, right & center pan supports, and drain

screen 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, and drain screen in compartment

and leave door slightly ajar.

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.

NOTE:

Total elapsed preheating time equals the timer

setting plus a short delay period needed to active a

thermostatic switch included in the controls.

CAUTION

When the unit is not in use, leave the cooking

compartment door slightly ajar to prolong the life of

the door gasket.

3-2

SECTION 3 OPERATION

PLUS - 12

STEAM

UPPER COMPARTMENT

LOWER COMPARTMENT

STEAM

LOWER COMPARTMENT

KETTLE

TIMER

TIMED

STEAM

OFF

CONSTANT

STEAM

oOFF

456

789

START

STOP

CLEAR

CONVECTION

STEAM

COOKER

STEAM

UPPER COMPARTMENT

LOWER COMPARTMENT

STEAM

LOWER COMPARTMENT

KETTLE

OFF

oOFF

MANUAL OPTION

DIGITAL OPTION

Figure 3-1 Controls & Indicators

3.4.2 Drip/Spill Trough Drainage

The ST-12 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 & INDICATORS

(See Figure 3-1)

REF. NUMBER

1



2



3



DESCRIPTION

Timer/Constant Steam



Indicator Light

Digital Timer

Mode Switch

FUNCTION

Controls cooking up to

60 Minutes or uses

constant operation.

Indicates cooker is in

operation.

Control cooking up to

99 minutes or constant.

Constant Steam/Timer

3-3

SECTION 3 OPERATION

TEST KITCHEN BULLETIN

Model ST-12 Pressureless Cooker

Facts On Parade

3.5 TEST KITCHEN BULLETIN

1. Frozen vegetables should always be cooked in perforated 12” x 20” x 2 1/2” (1/1 65mm) pans.

2. Frozen entrees should be underlined with a perforated pan for best results. If they are defrosted first, the heating

time will be decreased.

3. 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 2 1/2” (1/1 65mm) pans for the most nutritious results.

4. 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.

5. 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.

6. Compartments may be filled and timer set simultaneously.

7. Sheet pans will fit in compartment with the center rack removed.

8. All foods, except cakes and pastry, can be cooked in a steam cooking unit.

9. Steam cooked meals have greater nutritional value since they retain most of their vitamins and minerals.

10. Because foods are cooked faster by the higher temperatures of steam cooking, they can be prepared closer to

serving time, insuring maximum freshness.

11. Steam cooked foods have a higher percent yield more portions per dollar spent.

12. 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.

13. Some important advantages of steam cooking are labor saving, reduced operating costs, space saving, and the

lifting of heavy stock pots is eliminated.

14. Rice and spaghetti products, if thoroughly wet at the start of the cooking process, are very easily prepared.

15. 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.

16. Fuel is used only when the steam cooking unit is in operation.

17. The steam cooker will loosen foods burned on pans making washing easier.

18. Solid pans are recommended when liquid is to be retained and perforated pans when the liquid is not to be retained.

19. Eggs may be cooked out of the shell if they are to be chopped which eliminates peeling after steaming.

20. The steam cooker can be opened during the cooking period to add or remove items. If any time is lost, an

adjustment may be made on the timer.

21. 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 manual.

3-4

SECTION 3 OPERATION

The ST-12 Pressureless Cooker is a one compartment unit. The compartment holds twelve 12” x 20” x 2 1/2” 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 the 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

Beans, Lima

Broccoli

Brussel Sprouts

Carrots

Cauliflower

Corn-Cut

Mixed Vegetables

Peas (Loose)

Spinach

Squash

ITEM

Lobster Tails

6-8 oz. (170-255 g)

Shrimp, C.D.P.

Shrimp Green

Bulk Pack Frozen

Bulk Pack Defrosted

ITEM

Canned Vegetables

Approx. Number

Cooked Servings

Per Pan

30 3 oz. (85 g)

25 3 oz. (85g)

25 3 oz. (85 g)

30 3 oz. (85 g)

25 3 oz. (85 g)

30 3 oz. (85 g)

25 3 oz. (85 g)

30 3 oz. (85 g)

30 4 oz. (115 g)

50 3 oz. (85 g)

Approx. Number

Cooked Servings

Per Pan

15 6 oz. (170 g)

75 3 oz. (85g)

50 3 oz. (85 g)

10 6 oz. (170 g)

Approx. Number

Cooked Servings

Per Pan

25-30 3oz. (85 g)

Approx. Frozen

Weight

Per Pan

7 1/2 lbs. (3.4 kg)

6 lbs. (2.7 kg)

7 1/2 lbs. (3.4 kg)

6 lbs. (2.7 kg)

7 1/2 lbs. (2.7 kg)

6 lbs. (2.7 kg)

7 1/2 lbs. (3.4 kg)

7 1/2 lbs. (3.4kg)

9 lbs. (4kg)

12 lbs. (5.4 kg)

Weight Per Pan

7-8 lbs. (3.2-3.6 kg)

16-20 lbs. (7-9 kg)

3 1/2-4 lbs. (1.6-1.8 kg)

Weight Per Pan

7 lbs. (3.2 kg)

Recommended

12” x 20” (1/1)

Perforated Pan

2 1/2” (65mm)

Recommended

12” x 20” (1/1)

Perforated Pan

2 1/2” (65mm)

Recommended

12” x 20” (1/1)

Perforated Pan

2 1/2” (65mm)

Number

of Pans

Number

of Pans

Number

of Pans

Timer

Settings in

Minutes

12-15

10-15

5-7

12-15

4-6

10-15

7-12

8-12

3-5

Must be defrosted

Timer

Settings in

Minutes

15-25

8-11

11-15

35-45

25-35

Timer

Settings in

Minutes

5-10

FROZEN PREPARED ENTREES

VEGETABLES (CANNED)

3-5

SECTION 3 OPERATION

MEAT, POULTRY & FISH

PRESSURELESS STEAM COOKING TIMER SETTINGS & PORTIONS

VEGETABLES

ITEM

Beans, Snap Green

or Waxed

Beets (50mm) 2” E

Broccoli 1/2-3/4”

(12-20mm) Stalks

Carrots Sliced

Cauliflower, Trimmed

1 1/2-2” (38-50 mm)

Corn on Cob Husked

Cabbage Head 1/4-1/6

Cored

Onions (50 mm) 2" E

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

Diced Turnip

ITEM

Chicken Cut-up

Chicken, 4 lbs. Whole

Fowl, 5lbs. or more Whole

Fish, Fillets

Frankforts

Hamburgers3 oz. (85 g)

Meatballs 1 oz. (30 g)*

Approx. Number

Cooked Servings

Per Pan

25-30 3 oz. (85 g)

30-35 3 oz. (85g)

25-30 3 oz. (85 g)

35-40 3 oz. (85 g)

30-35 3 oz. (85 g)

15-20 4 oz. (115 g)

25-30 4 oz. (115 g)

25-30 3 oz. (85 g)

50 3 oz. (85 g)

10-12 3 3/4 oz. (105 g)

30-35 3 oz. (85 g)

25-30 3 oz. (85 g)

20-25 4 oz. (115 g)

Approx. Number

Cooked Servings

Per Pan

15-20 2 oz. Protein (55 g)

25-30 2 oz. Protein (55 g)

20-25 2 oz. Protein (55 g)

12-15 2 oz. (55 g)

35-40 2 oz. (55 g)

20-25 2 oz. Protein (55 g)

20-25 2 oz Protein (55 g)

Approx. Frozen

Weight

Per Pan

6 lbs. (2.7 kg)

7 1/2 lbs. (3.4 kg)

6 lbs. (2.7 kg)

9 lbs. (4 kg)

6 lbs. (2.7 kg)

1 doz.

5 lbs. (2.25 kg)

6 lbs. (2.7 kg)

5 lbs. (2.25 kg)

10 lbs. (4.5 kg)

3 lbs. (1.4 kg)

7 lbs. (3.2 kg)

9 lbs. (4 kg)

5 lbs. (2.25 kg)

Weight Per Pan

8 lbs (3.6 kg)

3 each

2 each

3 lbs (1.4 kg)

5 lbs (2.3 kg)

6 lbs (2.7 kg)

Recommended

12” x 20” (1/1)

Perforated Pan

2 1/2” (65mm)

Recommended

12” x 20” (1/1)

Perforated Pan

2 1/2” (65mm)

4” (100 mm)

2 1/2” (65mm)

Number

of Pans

Number

of Pans

Timer

Settings in

Minutes

18-22

40-50

14-18

18-21

12-16

10-15

14-18

20-25

5-6

18-21

35-40

3-5

7-10

10-15

28-32

Timer

Settings in

Minutes

20-30

45-50

50-60

10-15

3-5

18-22

20-25

3-6

SECTION 3 OPERATION

MISCELLANEOUS

PRESSURELESS STEAM COOKING TIMER SETTINGS & PORTIONS

MEAT, POULTRY & FISH CONTINUED

ITEM

Meatloaf*

Pork Chops, 4 oz.

Loin Bone (115 g)

Sausage 1 1/2 oz. (45 g)

Turkey On Carcass

TurkeyOff Carcass

ITEM

Eggs In Shell

Eggs Out of Shell

Rice — Bulletin 16

gives direction

Spaghetti — Bulletin 13

gives direction

Approx. Number

Cooked Servings

Per Pan

50-60 2 oz. Protein (55 g)

24 2 oz. Protein (55 g)

18-20 2oz. (55 g)

50-60 2 oz. Protein (55 g)

55-65 2 oz. Protein (55 g)

Approx. Number

Cooked Servings

Per Pan

36 -1 egg each

48 - 1 egg each

60-65 3oz. (85 g)

40-45 4oz. (115 g)

Approx. Frozen

Weight

Per Pan

15 lbs (6.8 kg)

6 lbs (2.7 kg)

20-22 lbs (9-10 kg)

10-12 lbs (4.5-5 kg)

Weight

Per Pan

3 dozen

4 dozen

4 lbs. (1.8 kg)

3 lbs. (1.4 kg)

Recommended

12” x 20” (1/1)

Perforated Pan

2 1/2” (65mm)

Recommended

12” x 20” (1/1)

Perforated Pan

2 1/2” (65mm)

4” (100mm)

Number

of Pans

Number

of Pans

12



12



12



Timer

Settings in

Minutes

40-50

25-30

18-21

2-2 1/2 hrs.

1-1 1/4hrs.

Timer

Settings in

Minutes

9-11

6-8

18-22

4-1

SECTION 4 PRINCIPLES OF OPERATION

4.1 General

The ST-12 Pressureless Steam Cooker consists of one

cooking compartment in a single cabinet assembly. The

compartment is fitted with an independent electrically

controlled steam circuit and spring-loaded, self-sealing

door with a slam action latch. The compartment can be

used 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 circuit consists of the piping, steam solenoid

valve, steam jet-pipe, drain, and cold water condenser

required to provide controlled steam application to the

cooking compartments. A simplified diagram of this circuit

is shown in Figure 4-1.

NOTE:

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.

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.

Steam inlet lines for the compartment are equipped with a

normally closed solenoid valve operated by the electrical

control circuit. The inlet valve is opened whenever the

compartment control circuit is activated by use of the 60-

minute timer.

4.2.1 Steam Inlet Line

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 the steam inlet solenoid

valve. 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 Steam Exhaust and Drain Lines

Perforated strainers at the drain line opening inside the

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 system for the compartment.

4.2.3 Steam Exhaust Condensing System

The steam condensing system consists of a, two-position,

normally closed cold water solenoid valve, 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 side is

connected remote from the supply line of the steam boiler

(or direct-connected steam plumbing). The valve responds

to a thermostatic switch located inside the compartment.

When the timer starts the cold water solenoids will

energize.

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.

4.3.1 Control Circuit Components

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.

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.”

4-2

SECTION 4 PRINCIPLES OF OPERATION

WATER INLET

FROM BOILER

STEAM LINE

TO CAVITY

STEAM LINE

TO CAVITY

STEAM LINE

FROM BOILER

STEAM JET PIPE

(2 PER COMPARTMENT)

WATER INLET TO

TOP CAVITY

WATER TO

DRAIN LINE

Figure 4-1 Pictorial Diagram, Steam & Water Circuits (Model ST-20 Shown Here)

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 Indicator Lights

An indicator light is included for the compartment. 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.

4.3.1.3 Buzzer

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.

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 nor-

mally 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.

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.

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

5-1

SECTION 5 TROUBLE-SHOOTING

5.1 General

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.

5.2 Trouble-Shooting Guides

A trouble-shooting guide for use by service personnel is

given in Table 5-1.

5.3 Electrical Fault Isolation

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.

PROBLEM

1. INDICATOR LIGHT FAILS TO

LIGHT WITH TIMER SET.

2. STEAM FAILS TO ENTER

COOKING COMPARTMENT WITH

INDICATOR LIGHT ON.

3. STEAM ENTERS COMPARTMENT

CONTINUOUSLY. TIMER DIAL NOT

TURNING.

4. STEAM CONTINUES TO FLOW

INTO COMPARTMENT AND/OR

BUZZER FAILS OT SOUND AT

END OF TIMER SETTING.

5. STEAM FLOWS CONTINUSLY

FROM BOILER (

OR DIRECT CONN-

ECTED STEAM CONTROL

) DRAIN LINE

WITH COOKER IN OPERATION.

PROBABLE CAUSE

a. Power to Cooker OFF.

b. Door Interlock Switch contacts

not closed.

c. Door Interlock Switch faulty.

d. Indicator Light burned out.

e. Faulty Timer contacts.

f. Faulty Wiring.

a. Faulty Steam Solenoid Valve.

b. Faulty Wiring.

a. Constant Steam Position.

b. Faulty Thermostatic Switch.

c. Faulty Timer Motor.

d. Faulty Steam Solenoid Valve.

e. Faulty Wiring.

a. Timer Contacts Faulty.

b. Buzzer Faulty.

c. Faulty Wiring.

a. Cold water not connected.

b. Faulty Thermostat.

c. Faulty Cold water.

d. Faulty Wiring.

REMEDY

a. Locate External Circuit Breaker for

incoming power & place in ON position.

b. Shut cooker door to close switch contacts,

Check alignment of door with switch.

c. Replace Switch (see subsection 5.4.4).

d. Replace Light.

e. Replace Timer (see subsection 5.4.3).

f. Inspect condition od wire & tightness of all