Market Forge ST-24M36300A Operators Manual

0

WARNING:

EQUIPMENT.

FOR YOUR SAFETY:

OF THIS OR ANY OTHER APPLIANCE.

Form Number: S-4627 Rev. B 10/12
Printed in USA 35 Garvey Street, Everett, MA 02149

Telephone [phone], Fax [phone]

[e-mail], www.mfii.com

CAUTION:

GAS SUPPLIER.

OWNER’S MANUAL

ST-24 PRESSURELESS STEAM COOKER

Model: □ ST-24

IMPROPER INSTALLATION, ADJUSTMENT,

ALTERATION, SERVICE OR MAINTENANCE CAN

CAUSE PROPERTY DAMAGE, INJURY OR DEATH.

READ THESE INSTALLATION, OPERATION AND
MAINTENANCE INSTRUCTIONS THOROUGHLY

BEFORE INSTALLING OR SERVICING THIS

DO NOT STORE OR USE GASOLINE OR OTHER

FLAMMABLE VAPORS OR LIQUIDS IN THE VICINITY

INSTRICTIONS TO BE FOLLOWED IN THE EVENT

THE USER SMELLS GAS SHALL BE POSTED IN A

PROMINENT LOCATION. THIS INFORMATION

SHALL BE OBTAINED BY CONSULTING THE LOCAL

INSTALLATION, OPERATION, MAINTANANCE, PARTS AND SERVICE

1

Table of Contents

INTRODUCTION .................................................................. 1

Description: .................................................................... 1

Basic Functioning: .......................................................... 1

Shipping Damage Claim Procedure: ............................... 1

Visible loss or damage: ............................................. 1

File claim for damages immediately: ........................ 1

Concealed loss or damage: ....................................... 2

Service: ........................................................................... 2

INSTALLATION .................................................................... 3

ASSEMBLY ...................................................................... 3

SETTING IN PLACE .......................................................... 3

MECHANICAL CONNECTIONS ......................................... 3

WATER CONNECTIONS ................................................... 3

INSTALLATION CHECK-OUT ............................................ 3

Initial Control Settings .............................................. 4

Cooker Check-Out .................................................... 4

Shut-Down Procedure .............................................. 4

REVERSING THE DOORS ................................................. 4

OPERATION ........................................................................ 7

OPERATING CONTROLS AND INDICATORS ..................... 7

OPERATING PROCEDURES .............................................. 7

Steam Source Operation .......................................... 7

Preheating ................................................................ 7

Cooking..................................................................... 7

Shut-Down Procedure .............................................. 8

Cleaning ......................................................................... 8

DRAINAGE ...................................................................... 8

Cooking Compartment Drainage .............................. 8

Drip/Spill Trough Drainage ....................................... 8

CONTROLS AND INDICATORS ......................................... 9

TEST KITCHEN BULLETIN .............................................. 10

Facts on Parade ...................................................... 10

COOKING GUIDE .......................................................... 11

PRINCIPLES OF OPERATION ............................................. 14

GENERAL ...................................................................... 14

PLUMBING CIRCUITS .................................................... 14

Steam Inlet Line ...................................................... 14

Steam Exhaust and Drain Lines .............................. 14

Steam Exhaust Condensing System ........................ 14

ELECTRICAL CIRCUITS ................................................... 15

Control Circuit Components ................................... 15

60 Minute Timer/Constant Steam .......................... 15

Indicator Lights ....................................................... 16

Buzzer ..................................................................... 16

Door Interlock Switch ............................................. 16

Thermostatic Switch ............................................... 16

Digital Timers (Optional) ........................................ 16

Kettle Switch (Optional) ......................................... 16

TROUBLE-SHOOTING ....................................................... 17

GENERAL ...................................................................... 17

Trouble-Shooting Guide .............................................. 17

Electrical Fault Isolation ......................................... 17

Electrical Trouble-Shooting Procedures ................. 17

GENERAL TROUBLE-SHOOTING GUIDE TABLE ............. 17

Incoming Power ..................................................... 18

Electrical Inspection ............................................... 18

ELECTRICAL FAULT ISOLATION GUIDE ......................... 19

60-MINUTE TIMER ....................................................... 19

Timer Contacts ....................................................... 19

Timer Motor .......................................................... 19

Door Interlock Switch ............................................ 20

Steam Solenoid Valves ........................................... 20

Indicator Lights ...................................................... 20

Cooking Compartment Thermostatic Switch ......... 20

Buzzer .................................................................... 21

Cold Water Condenser Circuit ............................... 21

Wiring .................................................................... 21

Wiring Diagrams .................................................... 22

MAINTENANCE ................................................................ 25

GENERAL ...................................................................... 25

PREVENTIVE MAINTENANCE ....................................... 25

Cooking Compartment Cleaning ............................ 25

Cleaning Procedure ................................................ 26

REPAIR AND REPLACEMENT ........................................ 26

DOOR LATCH TENSION ADJUSTMENT .................... 26

Door Handle Tension Adjustment .......................... 26

Door Gasket Replacement ..................................... 26

Exterior Panel Removal .......................................... 27

Steam and Water Solenoid Valve Replacement .... 27

ILLUSTRATED PARTS LIST ................................................. 28

Cabinet Assembly .................................................. 28

Cabinet Assembly Parts List ................................... 29

Door Latch and Handle .......................................... 30

Door Latch and Handle Parts List ........................... 30

Door Assembly ....................................................... 31

Door Assembly Parts List ....................................... 31

Control Panel Assembly ......................................... 32

Control Panel Assembly Parts List .......................... 32

Condenser Assembly ............................................. 33

Condenser Assembly Parts List .............................. 33

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 Steam
Cookers. Also included is a part list in which each replaceable part is identified and shown in an
accompanying exploded view.

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.

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.

Basic Functioning:

The Model ST-24 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 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.

Shipping Damage Claim Procedure:

The equipment is crafted and inspected carefully by skilled personnel before leaving the factory. The
transportation company assumes full responsibility for safe delivery upon acceptance of this equipment.
If shipment arrives damaged:

Visible loss or damage:

Note the damage or loss on freight bill or express delivery and signed by the person making the delivery.

File claim for damages immediately:

Regardless of the extent of damages.

2

Concealed loss or damage:

If damage is noticed after unpacking, notify the transportation company immediately and file a
"Concealed Damage" claim with them. This should be done within fifteen (15) days from the date

delivered. Retain container for inspection.

Service:

Installation of the equipment should be performed by qualified, certified, licensed and/or authorized
personnel who are familiar with and experienced in state/local installation codes.

Operation of the equipment should be performed by qualified and authorized personnel who have read
this manual and are familiar with the functions of the equipment.

Service of the equipment should be performed by qualified personnel who are knowledgeable with
Market Forge cooking equipment.

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 Industries Inc.

35 Garvey Street

Everett, Massachusetts 02149

Telephone [phone]

Toll Free [phone]

Parts and Service [phone]

Email [e-mail]

Website http://www.mfii.com/index.php/company/service for a listing of Authorized Service Agents.

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.

3

INSTALLATION

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 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.

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.

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.

WATER CONNECTIONS

Before connecting water to this unit, have water supply analyzed to make sure that hardness is no
greater 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.

EQUIPMENT FAILURE CAUSED BY INADEQUATE WATER QUALITY IS NOT COVERED UNDER WARRANTY.

CAUTION: PVC or CPVC are not acceptable materials for drains.

INSTALLATION CHECK-OUT

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. Refer to Cooker Check­Out on next page for the correct procedure. If the cooker fails to perform as described, consult 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
and with the function of each control. Refer to the section on Operation and Figure 2, Controls and
Indicators for identification of controls required in the following procedures.

4

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 timers for both compartments (see Figure 2 on page 9) are in the OFF position.

3. Cooker compartments are empty of all information materials, pan supports are mounted in

place, and doors are open.

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.

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.

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.

5

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 Figure 1 on page 6).

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 Figure 1 on page 6) 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.

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.

6

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.

Figure 1, Typical Door Layout

7

OPERATION

OPERATING CONTROLS AND INDICATORS

The controls and indicators required to operate the Pressureless Steam Cooker are listed in table on
page 9, together with a short functional description of each. Figure 2 on page 9 shows the physical
location of each control and indicator.

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.

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.)

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 “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. Turn off buzzer, which sounds to indicate cooking is complete, by setting the Timer Dial (1) to

OFF position.

Cooking

Before loading the cooker, be sure compartment is hot. Refer to Preheating Section for 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 (Refer to Facts on Parade on page 10).

5. Turn off buzzer, which sounds to indicate cooking is complete, by setting timer dial (1) to the

OFF position.

8

6. Open door slightly 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.

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.)

CAUTION:
When the unit is not in use, leave the cooking compartment door slightly ajar to prolong the life of the
door gasket.

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.

DRAINAGE

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.

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.

9

ITEM

PART NO.

DESCRIPTION

FUNCTION

1

08-6464

Timer/Constant Steam

Controls cooking up to 60 minutes or uses constant
operation.

2

10-5052

Indicator Light (Red)

Indicates cooking is in operation.

3

08-6429

Digital Timer

Control cooking up to 60 minutes or uses constant
operation.

4

08-6551

Mode Switch

Constant steam / Timer.

5

08-6549

Compartment Switch

Top and bottom cavity or kettle/BTM take-off.

Figure 2, Controls and Indicators (ST-24 Control Panel)

CONTROLS AND INDICATORS

ST-24 Control Panel

10

TEST KITCHEN BULLETIN

Model ST-24 Pressureless Steam Cooker

Facts on Parade

1. Frozen vegetables should always be cooked in perforated 12” x 20” x 2-1/2” pans 7-1/2 lbs. (34

kg) maximum per pan.

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” 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. Both compartments may be filled and timers set simultaneously.

7. Total cooking time will vary depending on the load, even though the timer setting is the same.

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 bulletin.

11

ITEM

Approx. Frozen

WT. Per Pan

Recommended

12” x 20” (1/1)

Perforated Pan

NO. of

Pans

Timer

Settings in

Minutes

Approx. NO.

Cooked Servings

Per Pan

Lbs.

kg

Asparagus,
Spears

7-1/2

3.4

2-1/2” (65mm)

10

12-15

30

3oz.

(85g)

Green Beans,
Regular

6

2.7

2-1/2” (65mm)

10

10-15

25

3oz.

(85g)

Green Beans,
French Cut

6

2.7

2-1/2” (65mm)

10

5-7

25

3oz.

(85g)

Beans,
Lima

7-1/2

3.4

2-1/2” (65mm)

10

12-15

30

3oz.

(85g)

Broccoli

6

2.7

2-1/2” (65mm)

10

4-6

25

3oz.

(85g)

Brussels
Sprouts

7-1/2

2.7

2-1/2” (65mm)

10

10-15

30

3oz.

(85g)

Carrots

6

2.7

2-1/2” (65mm)

10

10-15

25

3oz.

(85g)

Cauliflower

6

2.7

2-1/2” (65mm)

10

7-12

25

3oz.

(85g)

Corn,
Cut

7-1/2

3.4

2-1/2” (65mm)

10

8-12

30

3oz.

(85g)

Vegetables,
Mixed

7-1/2

3.4

2-1/2” (65mm)

10

8-12

30

3oz.

(85g)

Peas,
Loose

7-1/2

3.4

2-1/2” (65mm)

10

3-5

30

3oz.

(85g)

Spinach,
Defrosted

9 4 2-1/2” (65mm)

10

7-12

30

4oz.

(115g)

Squash,
Defrosted

12

5.4

2-1/2” (65mm)

10

7-12

50

3oz.

(85g)

ITEM

Approx. Frozen

WT. Per Pan

Recommended

12” x 20” (1/1)

Perforated Pan

NO. of

Pans

Timer

Settings in

Minutes

Approx. NO.

Cooked Servings

Per Pan

Lbs.

kg

Lobster Tails
6-8oz.
(170-255g)

7-8

3.2-3.6

2-1/2” (65mm)

10

15-25

15

6oz.

(170g)

Shrimp,
C.D.P.

16-20

7-9

2-1/2” (65mm)

10

8-11

75

3oz.

(85g)

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.

COOKING GUIDE

Frozen Vegetables

Frozen Prepared Entrees

12

ITEM

Approx. Frozen

WT. Per Pan

Recommended

12” x 20” (1/1)

Perforated Pan

NO. of

Pans

Timer

Settings in

Minutes

Approx. NO.

Cooked Servings

Per Pan

Lbs.

Kg

Shrimp,
Green

16-20

7-9

2-1/2” (65mm)

10

11-15

50

3oz.

(85g)

Bulk Pack,
Frozen

3-1/2 -4

1.6-1.8

2-1/2” (65mm)

10

35-45

10

6oz.

(170g)

Bulk Pack,
Defrosted

3-1/2 -4

1.6-1.8

2-1/2” (65mm)

10

25-35

10

6oz.

(170g)

ITEM

Approx.

WT. Per Pan

Recommended
12” x 20” (1/1)
Perforated Pan

NO. of

Pans

Timer

Settings in

Minutes

Approx. NO.

Cooked Servings

Per Pan

Lbs.

kg

Green Beans,
Snap or Wax

6

2.7

2-1/2” (65mm)

10

18-22

25-30

3oz.

(85g)

Beets,
2” Ø (50mm)

7-1/2

3.4

2-1/2” (65mm)

10

40-50

30-35

3oz.

(85g)

Broccoli, Stalks
1/2”-3/4”
(12-20mm)

6

2.7

2-1/2” (65mm)

10

14-18

25-30

3oz.

(85g)

Carrots,
Sliced 9 4

2-1/2” (65mm)

10

18-21

35-40

3oz.

(85g)

Cauliflower,
Trimmed 1-1/2
– 2” (38-50mm)

6

2.7

2-1/2” (65mm)

10

12-16

30-35

3oz.

(85g)

Corn on Cob,
Husked

1 doz.

2-1/2” (65mm)

10

10-15

12

Cabbage, Head
Cored 1/4-1/6

5

2.25

2-1/2” (65mm)

10

14-18

15-20

4oz.

(115g)

Onions,
2” Ø (50mm)

6

2.7

2-1/2” (65mm)

10

20-25

25-30

4oz.

(115g)

Peas,
Shelled

5

2.25

2-1/2” (65mm)

10

5-6

25-30

3oz.

(85g)

Potatoes,
French Fry Cut

10

4.5

2-1/2” (65mm)

10

10-21

50

3oz.

(85g)

Potatoes,
Regular Cut
3” (75mm)

10

4.5

2-1/2” (65mm)

10

35-40

50

3oz.

(85g)

Spinach,
Cleaned Cut

3

1.4

2-1/2” (65mm)

10

3-5

10-12

3.75 oz.
(105g)

Squash,Summer
1”Slices (25mm)

7

3.2

2-1/2” (65mm)

10

7-10

30-35

3oz.

(85g)

Squash, Winter
Peeled 9 4

2-1/2” (65mm)

10

10-15

25-30

3oz.

(85g)

Turnip,
Diced 5 2.25

2-1/2” (65mm)

10

28-32

20-25

4oz.

(115g)

Fresh Vegetables

13

ITEM

Approx.

WT. Per Pan

Recommended
12” x 20” (1/1)
Perforated Pan

NO. of

Pans

Timer

Settings in

Minutes

Approx. NO.

Cooked Servings

Per Pan

Lbs.

kg

Vegetables,
Canned

7

3.2

2-1/2” (65mm)

10

5-10

25-30

3oz.

(85g)

ITEM

Approx.

WT. Per Pan

Recommended
12” x 20” (1/1)
Perforated Pan

NO. of

Pans

Timer

Settings in

Minutes

Approx. NO.

Cooked Servings

Per Pan

Lbs.

kg

Chicken,
Cut Up 8 3.6

2-1/2” (65mm)

10

20-30

15-20

Protein

2oz.

(55g)

Chicken,
Whole 4 lbs.

3 Each

4” (100mm)

10

45-50

25-30

Protein

2oz.

(55g)

Fowl,
Whole 5 lbs. +

2 Each

4” (100mm)

10

50-60

20-25

Protein

2oz.

(55g)

Fish,
Filets 3 1.4

2-1/2” (65mm)

10

10-15

12-15

2oz.

(55g)

Hotdogs

5

2.25

2-1/2” (65mm)

10

3-5

35-40

2oz.

(55g)

Hamburgers,
3oz. (85g)

5

2.25

2-1/2” (65mm)

10

18-22

20-25

Protein

2oz.

(55g)

Meatballs,
1oz. (30g) Size*

6

2.7

2-1/2” (65mm)

10

20-25

20-25

Protein

2oz.

(55g)

Meatloaf*

15

6.8

2-1/2” (65mm)

10

40-50

50-60

Protein

2oz.

(55g)

Pork Chops,
Loin Bone
4oz. (115g)

6

2.7

2-1/2” (65mm)

10

25-30

24

Protein

2oz.

(55g)

Sausage,
1-1/2oz. (45g)

6

2.7

2-1/2” (65mm)

10

18-21

18-20

2oz.

(55g)

Turkey,
On Carcass

20-22

9-10

2-1/2” (65mm)

1

2 to 2-1/2

Hours

50-60

Protein

2oz.

(55g)

Turkey,
Off Carcass

10-12

4.5-5

2-1/2” (65mm)

10

1 to 1-1/4

Hours

55-65

Protein

2oz.

(55g)

ITEM

Approx.

WT. Per Pan

Recommended

12” x 20” (1/1)

Perforated Pan

NO. of

Pans

Timer

Settings in

Minutes

Approx. NO.

Cooked Servings

Per Pan

Lbs.

Lbs.

Eggs,
In Shell

3 Doz.

2-1/2” (65mm)

10

9-11

36

1 Egg

Each

Eggs,
Out of Shell

4 Doz.

2-1/2” (65mm)

10

6-8

48

1 Egg

Each

Rice –
Bulletin 16

4

1.8

2-1/2” (65mm)

10

18-22

60-65

3oz.

(85g)

Spaghetti –
Bulleting 13

3

1.4

4” (100mm)

10

18-22

40-45

4oz.

(115g)

Canned Vegetables

Meat – Poultry – Fish

*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

14

PRINCIPLES OF OPERATION

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.

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 3 on page 15.

NOTE: Figure 3 on page 15 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 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.

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 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.

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.

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

15

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.

Figure 3, pictorial Diagram, Steam and Water Circuits (Model ST-24)

ELECTRICAL CIRCUITS

The electrical circuits of the cooker control the power to activate timer motors and energize solenoid­operated 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 a certified
Electrician) is in the ON position.

Control Circuit Components

A brief description of the electrical circuit elements follows.

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

16

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.

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.

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.

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.

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.

Digital Timers (Optional)

The timer controls the steam to the cavity by either a constant steam setting or a used defined timer
that will be programmed by the user into the timer

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 separate direct
connected kettle can be used at the same time.

17

PROBLEM

PROBABLE CAUSE

REMEDY

1.

Indicator light fails to
light with timer set.

a.

Power to cooker off.

a.

Locate external circuit breaker for
incoming power and place in ON
position.

b.

Door interlock switch
contacts not closed.

b.

Shut cooker door to close switch
contacts. Check alignment of door with
switch.

c.

Door interlock switch
faulty.

c.

Replace switch. See Door Interlock
Switch on page 20.

d.

Indicator light burned out.

d.

Replace light.

e.

Faulty timer contacts.

e.

Replace timer. See 60-Minute Timer
on page 19.

f.

Faulty wiring.

f.

Inspect condition of wire and tightness
of all connections. Correct as needed.

2.

Steam fails to enter
cooking compartment
with indicator light on.

a.

Faulty steam solenoid
valve.

a.

Replace valve. See Steam Solenoid
Valves on page 20.

b.

Faulty wiring.

b.

Inspect condition of wire and tightness
of all connections. Correct as needed.

3.

Steam enters
compartment
continuously.
Timer dial not turning.

a.

Constant steam position.

a.

Move knob to timing location.

b.

Faulty thermostatic
switch.

b.

Replace switch. See Cooking
Compartment Thermostatic Switch on
page 20.

c.

Faulty timer motor.

c.

Replace timer. See 60-Minute Timer
on page 19.

d.

Faulty steam solenoid
valve.

d.

Replace valve. See Steam Solenoid
Valves on page 20.

e.

Faulty wiring.

e.

Inspect condition of wire and tightness
of all connections. Correct as needed.

TROUBLE-SHOOTING

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 the Operation section, pages 7-11. If the problem cannot be readily
corrected, the operator should contact the nearest Market Forge service agency for assistance.

Trouble-Shooting Guide

A trouble-shooting guide for use by service personnel is given in the table below.

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. The Electrical Fault Isolation table on page 19 is provided
as a guide for isolating electrical faults.

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 the Operation section as well as with the Principles of
Operation described in Principles of Operation section, pages 14-16.

GENERAL TROUBLE-SHOOTING GUIDE TABLE

18

PROBLEM

PROBABLE CAUSE

REMEDY

4.

Steam continues to
flow into compartment
and/or buzzer fails to
sound at end of timer
setting.

a.

Timer contacts faulty.

a.

Replace timer. See 60-minute timer on
page 19.

b.

Buzzer faulty.

b.

Replace buzzer. See Buzzer on page

21.

c.

Faulty wiring.

c.

Inspect condition of wire and tightness
of all connections. Correct as needed.

5.

Steam flows
continuously from
boiler (or direct
connected steam
control) drain line with
cooker in operation.

a.

Cold water not
connected.

a.

Turn on external shut-off valve.

b.

Faulty thermostat.

b.

Replace thermostat. See Cooking
Compartment Thermostatic Switch on
page 20.

c.

Faulty cold water
solenoid.

c.

Replace valve.

d.

Faulty wiring.

d.

Inspect condition of wire and tightness
of all connections. Correct as needed.

GENERAL TROUBLE-SHOOTING GUIDE TABLE CONTINUED

The electrical trouble-shooting procedures that follow require access to components and terminals of
the electrical control panel shown in Figure 10, on page 32. 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.

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.

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 Exterior Panel
Removal on page 27.

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.

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 quick­disconnect terminals for evidence of corrosion. Terminals in this condition should be separated, cleaned
with emery cloth until shiny, and tightly reconnected.

WARNING:

19

FAILURE

FAULT LOCATION

1.

Will not operate in either CONSTANT STEAM or 60­MINUTE TIMER positions.

a.

Incoming power

b.

Timer

c.

Door interlock switch

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 when 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.

Compartment thermostatic switch

b.

Constant steam position

c.

Timer motor

d.

Wiring

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

ELECTRICAL FAULT ISOLATION GUIDE

60-MINUTE TIMER

Timer Contacts

Defective timer contacts will result in failure of either cooker compartment to operate. When this occurs,
remove the control panel (see Exterior Panel Removal on page 27), 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 4 on page 22).

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.

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 4 on page 22.

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 Cooking Compartment Thermostatic
Switch on page 20).

20

To confirm timer motor condition, proceed as follows:

1. Carefully check motor wire leads and tighten loose connections.

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.

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:

1. Turn off power to the cooker.

2. Disconnect wires to the door switch terminals (see Figure 4 on page 22).

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 4 on page 22).

Steam Solenoid Valves

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.

Indicator Lights

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).

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. 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.

21

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).

Cold Water Condenser Circuit

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
Cooking Compartment Thermostatic Switch on page 22.

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.

Wiring

All of the electrical components of the cooker (timers, indicator lights, etc.) are connected to each other
by wiring shown in Figure 4 on page 22. 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.

Figure 4, on page 22 is a diagram that shows all terminals and interconnections within the electrical
circuits. All numbered terminals are identified and all leads number coded as shown. Connections can be
easily removed.

Figure 5, on page 23 shows the same information schematically and is an aid in isolating circuits for
testing. Using an ohmmeter, wiring continuity between the connections shown on the wiring diagram
(Figure 4 on page 22) 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.

22

Wiring Diagrams

Figure 4, Wiring Diagram, Mechanical Controls, Model ST-24

23

Figure 5, Wiring Diagram, Digital Controls, Model ST-24

24

Figure 6, Wiring Ladder Diagram, Model ST-24

25

Product Service Department

Market Forge Industries Inc.
35 Garvey Street
Everett, Massachusetts 02149
Telephone [phone]
Toll Free [phone]

Website

http://www.mfii.com/index.php/company/service

for a listing of Authorized Service Agents.

Parts and Service [phone]

Email Us at [e-mail]

MAINTENANCE

WARNING:

DO NOT HOSE DOWN UNIT AS IT CONTAINS ELECTRICAL COMPONENTS!

GENERAL

This section contains both preventative maintenance 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 the user personnel never attempt to make repairs or
replacements to the equipment without the assistance of an authorized service agent. Assistance in
service may be obtained from Market Forge Industries.

A current Directory of Authorized Service Agencies may be obtained by contacting:

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.

PREVENTIVE MAINTENANCE

A good preventive maintenance program starts with the daily cleaning procedure (see Cleaning
Procedure on page 26.

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
experience should be performed by an authorized service agent.

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.

Cooking Compartment Cleaning

A daily cleaning of the cooking compartment(s) and pan supports is required.

26

Cleaning Procedure

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.

REPAIR AND REPLACEMENT

The Illustrated Parts List section of this manual contains a listing of all replacement 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 the procedures that are not readily apparent.

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.

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.

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.

3. Remove the eight nuts from the door gasket mounting plate on the inside of the inner door

assembly.

4. Remove the door gasket mounting plate and the door gasket.

5. Install the new door gasket (see Figure 9 on page 31 for part number) to the mounting plate.

6. Reassemble the mounting plate with gasket to the inside of the inner door assembly using the

eight nuts.

27

7. Reassemble the inner door assembly using the six screws on the outside of the door.

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.

Procedure—To Adjust Gasket to Unit:

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.

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 left­side 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 on page 28. The electric control panel,
shown in Figure 10 on page 32, 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.

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 Exterior Panel Removal shown above.

28

Cabinet Assembly

ILLUSTRATED PARTS LIST

Figure 7, Cabinet Assembly

29

Cabinet Assembly Parts List

ITEM

PART NO.

DESCRIPTION

QTY.

1

08-6308

REED SWITCH

2 2 08-4912

ASSEMBLY, PLUMBING DRAIN

2 3 10-2793

REAR POST

2 4 98-1643

COUPLER, 1/2” NPT X 5/8” ID BARB

4 5 08-6538

ELBOW, 90O, 1/2“ IPS

4 6 98-1643

BRACKET, REAR FRAME SUPPORT

1 7 08-6538

CHECK VALVE, 3/8 OD BLACK

2 8 91-6491

GROMMET, SILICONE RED

2 9 91-7639

BRACKET, CAVITY SUPPORT

1

10

91-7318

WELD ASSEMBLY, TOP

1

11

10-9174

RELAY, TUBE

4

12

10-9175

RELAY, BASE

4

13

91-6940

BRACKET, RELAY

2

14

91-6475

HINGE, ASSEMBLY TOP

2

15

91-6476

HINGE, ASSEMBLY BOTTOM

2

16

91-7334

TROUGH, DRIP ST-24

1

17

91-7385

ASSEMBLT, DOOR ST-24

2

18

91-5621

ASSEMBLY, JET PIPE

4

19

91-6492

LATCH, DOOR

2

20

08-4600

SPRING, COMPRESSION

4

21

98-1637

MECHANICAL CONTROL PANEL WITH SWITCH

1

22

91-7684

STRAINER, CAVITY

2

23

98-1605

WELD ASSEMBLY, MIDDLE RACK

2

24

91-7699

RACK SIDE

4

25

10-4586

NUT, 1/2“ IPS, S.S. WITH TEFLON

6

26

10-8105

THERMOSTAT, SNAP DISC, PROBE TYPE

2

27

10-3343

NUT, BRASS, 1/2“ IPS

2

28

10-1956

SCREW, TAPTIGHT, 8-32 X 3/8“

20

29

10-2571

NUT LOCK, 8-32

17

30

08-1204

PLUG, HOLE WHITE

4

31

10-2184

SCREW, HEX HEAD, 10-32, 3/4“ LG

8

32

91-7569

PANEL, SIDE

2

33

91-7327

PANEL, REAR

1

34

98-1632

INSULATION, FRONT

1

35

98-1631

INSULATION, REAR

1

36

08-7959

TUBING, NORPRENE 3/8” ID

*

37

08-7960

TUBING, NORPRENE 5/8” ID

*

38

98-1638

MECHANICAL CONTROL PANEL WITHOUT SWITCH

1

39

98-1639

DIGITAL CONTROL PANEL WITH SWITCH

1

40

98-1640

DIGITAL CONTROL PANEL WITHOUT SWITCH

1

41

08-2702

BUSHING, DOOR, WHITE

4

42

91-7690

BRACKET, REED SWITCH

2

* AS MEASURED.

30

Door Latch and Handle Parts List

ITEM

PART NO.

DESCRIPTION

QTY.

1

91-5669

LATCH (OLD VERSION)

2 2 91-6734

HANDLE (OLD VERSION)

2 3 91-5745

HANDLE (NEW VERSION)

2 4 91-6492

LATCH (NEW VERSION)

2

Door Latch and Handle

Figure 8, Door Latch and Handle, Model ST-24

31

Door Assembly Parts List

ITEM

PART NO.

DESCRIPTION

QTY.

1

91-7386

OUTER DOOR

1 2 91-7387

INNER DOOR

1

3

91-7388

GASKET RETAINING PLATE

1 4 91-7389

DOOR GASKET

1

5

91-5745

DOOR HANDLE

1 6 09-1608

STRIKER

1

7

08-5027

MAGNET

1 8 91-5901

MAGNET BRACKET

1

9

08-4600

COMPRESSION SPRING

2

Door Assembly

Figure 9, Door Assembly

32

Control Panel Assembly Parts List

ITEM

PART NO.

DESCRIPTION

QTY.

1

98-1616

CONTROL PANEL

1 2 98-1612

LEXAN, CONTROL PANEL

1 3 08-6464

60-MINUTE TIMER

2 4 08-6541

TERMINAL STRIP

2 5 91-6471

BRACKET, TERMINAL STRIP

2

6

10-7395

BUZZER 2 7

08-3826

KNOB, TIMER

2 8 10-5052

LIGHT, RED

2

Control Panel Assembly

Figure 10, Control Panel Assembly

33

Condenser Assembly Parts List

ITEM

PART NO.

DESCRIPTION

QTY.

1

10-5859

VALVE, STEAM SOLENOID

1 2 08-4892

COUPLER, BRASS 3/8 OD X 1/2 THRD NPT

2 3 10-2885

UNION, FEMALE 1/2 IPS

1 4 10-2849

NIPPLE, CLOSE 1/2” NPT BRASS

2 5 98-1477

COUPLER, BRASS, BARB 3/8” X 3/8” NPT

1 6 08-6581

TEE, MALE 1/2” NPT X FEMALE 1/2“ BRANCH

1 7 10-3739

1/2” X 3/8 REDUCING BUSHING

1

8

98-1630

WELDMENT, COLD H20 STEAM VALVE

1 9 10-1055

TEE, 3/8” ALL ROUND

1

10

10-3644

PLUG, SQUARE HEAD 3/8” IPS, BRASS

1

11

08-7525

MIPPLE, CLOSED 3/8” NPT, BRASS

2

12

08-6498

VALVE, 3/8” NPT, COLD WATER CONDENSER

1

13

08-4912

COUPLER, BARB 5/8” OD X 1/2“ IPS

1

14

08-7962

COUPLER, BARB 5/8” OD X 3/8“ IPS

1

15

98-1477

COUPLER, BRASS BARB 3/8” X 3/8“ THD NPT

1

Condenser Assembly

Figure 11, Condenser Assembly