constitute a remarkable and superior feature.
Each compartment can be used alone, or all three
can be employed simultaneously because each has
its own timing, steam control and signal devices.
The careful factory workmanship of Market Forge
craftsmen in developing this newest scientific
triumph in steam cooking equipment is your
guarantee of efficient, dependable performances.
HOW TO USE THIS MANUAL
This manual contains maintenance and service instructions for Model "A" and "A-1" automatic and
manually operated steam cookers. The exploded
view drawings of components are aids to the
identification, disassembly and assembly of parts.
The parts listings provide information necessary for
ordering replacement parts (proper part names and
part numbers). When requesting parts or service,
always furnish the model and serial number of your
machine. The serial number is located on the left
side under the bezzel on the con-trol panel. A
listing of Factory Aut horized Service Agencies who
maintain Market Forge equipment will be supplied
without charge upon request.
ORDERING REPAIR PARTS
Many repair parts on the Model "A1" steam
cooker are not interchangeable with parts on
the "A" cooker. It is necessary, therefore, to
furnish the following information when ordering
repair parts.
1. Quantity, part number and description of
part.
2. Model and Serial number for which the part
is required.
3. Please specify how you wish merchandise
shipped. If this information is not furnished
we will ship the best and most economical
way.
NOTE- All part orders received before 2:00
P.M. are shipped the same day the order is
received.
BASIC OPERATING INSTRUCTIONS FOR
AUTOMATIC
1. Check to be sure the steam pressure gauge
regis-ters between 4 and 5 pounds.
2. Place pans of food into the cook ing
compartment to be used.
3. Close and latch the door.
4. Turn the door wheel clockwise to seal the
cooking compartment.
WARNING: Do not permit steam to leak.
Set the door tight enough to make a firm
seal. Steam leakage will cause undue
wear to the gasket.
5. Turn timer pointer clockwise to the 60 minute
mark, and then to the desired cooking time.
6. Pull the-operating handle out and allow it to
lock in this position. The pilot light will signify
this cooking compartment is in operation. At
the end of the cooking cycle the AUTOMATIC
controls will release the operating handle,
shutting off the steam supply and exhausting
the steam from the cooking com-partment.
The pilot light will be turned off and the
buzzer will signify that cooking has been
terminated.
7. Press the buzzer release knob to silence the
buzzer.
FOR MANUALLY OPERATED
1 through 5
6. Set timer. When bell rings, lift handle and
push in to shut off cooker.
10-5847 Name plate Panel (3 comp.)
90-8312 Name plate Panel (4 comp.)
38 10-4619*
39 10-4559*
40 10-1975
41 10-2505 Lock Washer
42 10-2160
43 909237
44 10-2154
45 90-9186
46 10-1949
47 90-9184
10-5625*
90-4003*
909238
90-9187
90-9231
90-9896
90-9185
90-9232
Replacement element for Steam Trap
Replacement element for Steam Trap
1/2" Steam trap complete
1/2" Steam trap complete
No. 4-
No. 10-32 x 3/8 Phil Truss
Top Cover Ass'y. Top Cover Ass'y. No. 10 Bottom Enclosure Bottom Enclosure —
No. 6
Back Side Enclosure Back Side Enclosure -
Manifold Compartment A Cooker Automatically Operated
5
3343*
Lock nut Nickel Plated
exhaust header
Rd hd mach screw cad
(OBSOLETE)
Master Illustration Parts List
* INDICATES INTERCHANGEABLE
PARTS A1 & 'A' COOKER
Item Part No. Description
1 10-2445* 1" OD x 3/8 St. St. Washer
2 10-2328* 1/4-20 Elastic stop nut
3 10-2652* 7/8 x 1 x 1/16 Composition Gasket
4 10-1910 3/16" Tube x 1/8" Taper pipe thread
10-
1/2"
7 90-8387 1/2" I.D. plated washer
8 10-2757 3/8" O.D. x 1" long Spring
9 90-8546 Shaft for reset button
10 90-8545 Bracket for reset button
11 90-8524 Latch handle assembly
12 90-8550 Operating Arm Assembly
13 90-8547 Left Bracket
14 10-1975 4-40-1/2 Flat hd. screw
15 10-2505* 10/32 x 1/16" Lock washer
16 10-2339 10/32 St. St. hex nut
17 10-2755* Spring for Operating Arm
18 90-8531 Spring Bracket
19 10-1908 1/8" x 1 1/ 4" drive pin
20 90-8669 Operating Handle
21 10-1922 8/32 x 1/2 Oval hd. screw cad. pl.
22 90-8534* Pivot Arm
23 10-1852 10/24 x 3/4 Rd. Hd. mach. screw
24 90-8537* Valve actuating arm
25 90-8533 Shoulder Screw for Linkage
90-8573 Side Enclosure St. St. 2 comp.
26
90-8575 Side Enclosure St. St. 3 comp.
90-8577 Side Enclosure St. St. 4 comp.
90-8574 Side Enclosure Painted 2 comp.
90-8576 Side Enclosure Painted 3 comp.
90-8578 Side Enclosure Painted 4 comp.
27 10-2756* Valve Synchronizer Spring
28 10-1845 8/32 x 1/4 St. St. self tapping screw
29 10-5514* 0-60 minute electric timer
30 10-5499 115V Pilot Light
31 10-4713 Timer knob
32 10-4748* 0-30# Pressure Gauge
90-8683 Bezel 2A 33
90-8684 Bezel 3A
34 10-2339 #10 Hex nut St. St.
Item Part No. Description
90-8549* Manifold Shield St. St. 35
90-8541 Manifold Shield Painted
36
90-8434 Side Panel St. St. 2 comp .
90-8435 Side Panel St. St. 3 comp.
90-8436 Side Panel St. St. 4 comp.
90-8430 Side Panel Painted 2 comp.
90-8431 Side Panel Painted 3 comp.
90-8432 Side Panel Painted 4 comp.
37 10-4563 Buzzer
38 10-1888 #10 Cad plated lock washer
39 10-5613* Solenoid Micro switch
40 90-4159 Insulator
41 10-2337 6/32 St. St. hex nut
42 10-2503* 3/8" Lock washer cad. pl.
43 10-2124* 3/8" - 16 x 1 1/8" hex hd. cap screw
44
48 10-2508 1/4 x 3/32 x 1/16 St. St. lock washer
49 90-8542 Push rod for Solenoid
50 10-2515* #6 x 3/6 x 1/32 lock washer cad pl
51 10-1760 10/32 x 1/2" St. St. mach screw
52 90-4399 Spring clip
53 90-8739 Panel clip
54
1 10-2445* 1"O.D.x 3/8" St. St. Washer
2 10-2328* 1/4-20 Elastic Stop Nut
3 10-2652* 7/8x1 x 1/16 Composition Gasket
4 10-1910
5 10-3343* 1/2" Lock nut Nickel Plated
6 10-2988* 1/2" x 3 1/2" Rd.Hd. Rivet
7 90-8387 1/2" I.D. Plated Washer
8 10-2757 3/8" O.D. x 1" Long Spring
9 90-8524 Latch Handle Assembly
10 90-8550 Operating Arm Assembly
11 10-2755* Spring for Operating Arm
12 90-8669 Operating Handle
13 10-1922 8/32 x 1/2 Oval Hd. Screw Cad. PI.
14 90-8534* Pivot Arm
15 90-8537* Valve Actuating Arm
16 10-1967* Shoulder Screw for Linkage
90-8573 Side Enclosure St. St. 2 Comp.
18 10-2756* Valve Synchronizer Spring
19 10-1845 8/32 x 1/4 St. St. Self Tapping Screw
20 10-5220* 0 - 60 Minute Mechanical Timer
21 10-4713 Timer Knob
22 10-4748* 0 - 30# Pressure Gauge
23 90-8683 Bezel 2A
24 10-2339 #10 Hex Nut St. St.
90-8575 Side Enclosure St. St. 3 Comp.
90-8577 Side Enclosure St. St. 4 Comp.
90-8574 Side Enclosure Painted 2 Comp.
90-8576 Side Enclosure Painted 3 Comp.
90-8578 Side Enclosure Painted 4 Comp.
32 10-1921 Retaining Screw - Side Enclosure
33 10-4619* Replacement Element for Steam Trap
34 10-4742* 3/4" - 8# Safety Valve Chrome
35 10-3455 3/4" B. 1. Elbow
90-8541 Manifold Shield Painted
90-8434 Side Panel St. St. 2 Comp.
90-8435 Side Panel St. St. 3 Comp.
90-8436 Side Panel St. St. 4 Comp.
90-8430 Side Panel Painted 2 Comp.
90-8431 Side Panel Painted 3 Comp.
90-8432 Side Panel Painted 4 Comp.
90-8498
90-8496
90-8604
90-4003* 1 /2" Steam Trap Complete Chrome
10-5625* Replacement Element for Steam Trap
10-4741* 3/4" - 8# Safety Valve Brass
90-7304 3/4 "Chrome Elbow
10-0435 Name Plate 2A
10-0434 Name Plate 3A
90-8583 Name Plate 4 A Upper
90-8588 Name Plate 4A Lower
1 90-8310 Model A-1 Hand Grip
2 10-1945 Gasket Screws
3 90-8311 Model A-1 Gasket Plate
4 10-0433 Model A-1 Door Gasket
5 90-8514 Model A-1 Inner Door
6 10-2135 5/16-18 x 3/4 Hex. Hd. Bolt
7 10-2426
8 10-1909 5/16" Thredseal
9 90-8114 Spring Door Release
10 10-3079 (Pivot Bearing Interchangeable)
11 10-2427
12 90-8111 Hinge — Polished upper and lower
90-8316 Hinge — Enameled upper and lower
90-8147 Inner Door Ass'y (Items 1-5)
ITEM PART NO. DESCRIPTION
13 10-1981 Pivot Hinge
14 90-8113 Handwheel — Polished Solid
90-8328 Handwheel -Spoked (Enamel)
15 90-8126 Outer Door Ass'y.— Polished
90-8320 Outer Door Ass'y.— Enameled
16 10-2423 Thrust Washer
17 10-3080 Door Bushing
18 10-1696 Roll Pin
19 90-8124 Strong Back
20 10-2012 Cap Screw
21 10-1973 Support Stud Ass'y.
22 10-2302 Hex. Nut 3/8-16
23 90-8317 (Bushing for spoke wheel only)
24 10-2013 Hex. Jam Nut 3/8-16
5106
Page 13
5107
Item Part No. Description
1 90-8518 Model A Gasket Plate Handle
2 10-1704 Gasket Screws
3 90-8517 Model A Gasket Plate
4 10-0433 Model A Door Gasket
5 90-8514 Model A Inner Door
6 90-8504 Model A Outer Door
7 10-2124 3/8" Hex Head Cap Screw x
1-1/8" long St. St.
8 10-2426 11/32 I.D. x 3/4'
O.D. Flat Washer
St. St.
90-8519 Inner Hinge Bracket - Top -
Polished
9
10-0427Inner Hinge Bracket - Top -
Painted
10 10-1909 5/16" Thread seal
11 90-8523 Spring Door Release
12 10-4121 Retaining Ring
13 90-8879 Door Hinge Pin
90-8677 Outer Hinge Bracket - Polished 14
10-0474 Outer Hinge Bracket - Painted
90-8520 Inner Hinge Bracket - Bottom -
Polished
15
10-0426 Inner Hinge Bracket - Bottom -
Painted
16 90-8559 Handwheel stainless steel
90-
8560 Handwheel painted
17 90-8680 Outer Shell Assembly painted
90-8507 Outer Shell Assembly St. St.
18 10-1690 Roll Pin
19 10-2423 Thrust Washer
20 90-8511 Door Bushing
21 90-8480 Door Latch
22 10-2426
11/32" I.D. x 3/4" O.D. Flat Washer
St. St.
23 10-1907 1/4-
20 x 5/8" long Hex Head Screw
cad. plated
24 90-8513 Strong Back
25 10-2071 3/8-
To provide adequate steam pressure regulation, your
unit may be equipped with a Wat ts steam pressure reducing valve. The 3/4" Watts pressure reducing valve is
designed to operate from a 7 to 50 P.S.I, source of
steam pressure and reduce this to 5 P.S.I, for delivery to
your cooker. Installation must be made from your source
of steam supply, through the pressure reducing valve,
and into the manifold input part of the steam cooker.
WARNING: Before final connection is made, blow
down your steam line to remove all dirt, scale,
packing and compound which may have
accumulated during the installation of piping to the
cooker.
OPERATION OF WATTS 3/4" REDUCING VALVE
Steam enters the valve at the inlet port and passes upward through the seat (8) into the discharge side of the
valve. As pressure in the discharge side increases, it
forces the diaphragm (2) upward, overcoming the tension
of the adjusting spring (1) and closing valve. As the
pressure drops, the adjusting spring forces the
diaphragm down, reopening the valve. Where demand
and initial pressures are fairly constant, the valve opens
to the proper position and maintains the desired re duced
pressure.
ADJUSTING WATTS 3/4" REDUCING VALVE
1. Release the adjusting screw lock nut and loosen the
adjusting screw enough to release all tension on adjusting spring (1).
2. Turn steam on slowly. Then turn adjusting screw
clockwise just enough to allow the valve to open
slightly. Allow cooker to operate in this manor
several minutes.
3. Turn adjusting screw down slowly, at intervals,
until reduced pressure reaches the desired Point.
(5 P.S.I.)
4. Tighten adjusting screw lock nut.
5. If chattering noise should occur turn adjusting screw
located in bottom half of valve body, clockwise or
counter-clockwise, until chattering stops.
INSPECTION - MAINTENANCE
Reports of unsatisfactory regulation of the pressure
reducing valve is usually due to dirt, pipe compound,
etc., blocking the internal strainer, or gumming up the
seat and disc assembly. To clean the strainer, seat,
and disc assembly remove the bottom plug (6) and
remove strainer screen (5), bottom spring (7) and disc
assy. (9) Clean the lower part of the valve. This can be
accom plished without removing the valve from the line
or unbolting the cover. If cleaning the strainer and disc
assy. does not correct fault, the disc assy. and seat
should be replaced. Also the top cover should be removed and the diaphragm button stem assembly
should be removed and cleaned.
REPAIRS
The following item should be cleaned or replaced
should the value fail to operate properly.
1. Both the disc assembly (9) and strainer (5) are removed by removing the bottom plug (11) and bottom
spring (7). Upon cleaning or replacing these items,
be sure that the disc assembly (9) is seated properly
on the stem assembly (4) otherwise the stem
assembly will be bent restricting its mov ement and
the regulation of steam through the valve.
2. Should there be a restriction in the diaphragm button
and stem assembly (4) it will cause a drop in steam
flow or large fluctuations in steam pressure. It is
then necessary to replace diaphragm but ton and
stem assembly (4), valve stem guide (12) and
diaphragm gasket (3) as well as those items in step
1.
Upon completion of the above and removal of any
loose scale, which may be found in the valve, the valve
should be reassembled; and upon installation, function
properly.
5010
Page 15
STRONG PRESSURE REDUCING VALVE
Item Description
Part No
2 Adjusting Spring Cap
10-4825
3
Spring Washer
10-4826
4 Adjusting Spring, Green
15
Ib 10-
4827
5 Cover
104828
6 Upper Stem Guide
104829
7
Upper Diaphragm Block
10-4830
8 Cover Gasket
10-4831
9 Diaphragm (with gasket)
10478
2 10 Body (with seat insert)
10-4832
11
Lower Diaphragm Plate
10-3833
13 Strainer Screen
10-4783
14 Disc (pressed on stem)
10-4835
TYPE "K"— 3/4 INCH
(OBSOLETE)
3/4" PRESSURE REDUCING VALVE Parts List
1 Adjusting Screw 104824
12 Seat Insert 10-4834
15 Bottom Plug 10-4836
ADJUSTING TYPE K REDUCING VALVES
1. Release the adjusting screw lock nut and loosen
adjusting screw (1) enough to release all tension
on adjusting spring (4).
The 3/4" Strong Pressure Reducing Valve, Type K is
designed to operate from a 20 to 100 P.S.I, source of
steam and reduce this to 5 P.S.I, for delivery to your
steam cooker.
With the introduction of a pressure reducing valve to
your input line, it is recommended that a pressure gauge
be also installed on the supply side so that the actual
steam input pressure may be constantly record-ed. The
selection of a pressure gauge must be made to operate
within the range of pressure experienced from your
source of supply. The reduced pressure may con-stantly
be read on the steam cooker pressure gauge.
WARNING: Before final installation connection is made,
blow down your steam line to remove all
dirt, scale, packing, and compound which
may have accumulated within the new
piping.
OPERATION OF TYPE K REDUCING VALVES
Steam enters inlet port and passes upward through seat
(12) into discharge side of valve. As pressure in
discharge side increases, diaphragm (9) is forced
upward overcoming tension of adjusting spring (4) and
closing valve. As pressure drops, adjusting spring (4)
forces diaphragm (9) down, reopening valve.
2. Turn steam on slowly. Then turn adjusting screw (1)
down just enough to allow the valve to open slightly.
Allow cooker to operate in this manner several
minutes.
3. Turn adjusting screw (1) down slowly, at intervals
until reduced pressure reaches the desired point.
4. Tighten adjusting screw lock nut.
INSPECTION - MAINTENANCE - REPAIRS
Reports of unsatisfactory regulation of the pressure
reducing valve is usually due to dirt, pipe compound,
etc., blocking the internal strainer or gumming up the
internal mechanism. To clean the strainer, unscrew
bottom plug (16) and remove strainer screen (13).
Clean the lower part of the valve. This can be accomplished without removing the valve from the line or
unbolting the cover. If cleaning the strainer does not
correct fault, remove the valve from the line and disassemble. After thoroughly cleaning, the seat insert
(12) and disc (14) should be ground together, using a
very fine abrasive or compound. The seat insert and
disc are of the ball type and must be "wobbled" when
lapping. Avoid excessive lapping as this will cause
ridges to form and make tight seating impossible.
5108
Page 16
THE STEAM MANIFOLD AND VALVE ASSEMBLY
The steam manifold and valve assembly provides a means of
steam input and exhaust control for each cooking compartment.
Though complete removal of the manifold and valve assembly
will be necessary to replace a complete valve, each may be
serviced in its position by following these service instructions.
TO DISASSEMBLE VALVE
1. Shut off the steam supply to the cooker.
2. Unfasten the pivot arm at points A and B.
3. Unfasten the valve synchronizer spring at point C
remove to free valve actuating arm and spacer.
4. Remove the pivot stud to allow more working room.
5. Remove valve cap (6) and valve bonnet (1).
6. Pull out valve synchronizer (3).
7. Lift out valve synchronizer lever and ball
assembly (5).
8. Insert a pencil in the hole of valve synchronizer
ball (4) and lift out through the front portal.
TO ASSEMBLE VALVE
1. Slip valve synchronizer ball (4) into the valve with
the hole facing the front portal.
2. Drop valve synchronizer lever and ball assembly (5)
in from the top opening of the valve with cut out on
the lever facing ball (4).
3. Manipulate valve synchronizer (3) in position (large
prong in ball - smaller prong in lever).
4. Screw on valve bonnet (1) and valve cap (6).
5. Place the spacer over the shaft of the valve
synchronizer.
6. Place the valve actuating arm over the shaft of
the valve synchronizer with the bushing facing
the valve.
7. Fit the valve synchronizer spring into the hole in the
shaft of the valve synchronizer and secure it in
place with the screw and the flex-loc nut.
8. Secure the pivot stud into the wall and assemble
the pivot arm fastening at point A and then at point
B.
8 10-2696 Valve Body Gasket
9 90-2443 Exhaust Valve Seat
10 90-2434 Supply & Exhaust Valve - comp.
Page 17
TO SERVICE SUPPLY VALVE AGAINST LEAKS
Remove the interference of the pivot arm by detaching
it at the actuating arm junction and from the pivot stud.
Remove the pivot stud and proceed as follows:
1. Remove existing valve cap (6). (It is not necessary to remove the valve.)
2. Replace valve cap (6) with the seating tool after
having retarded the bolt to a point where it will not
prematurely strike the ball in the valve.
3. After the seating tool-is well secured, screw down
the bolt to make contact with the ball assembly and
apply pressure to force the ball to "make" a new
seat.
4. Remove the seating tool and replace it with
original valve cap(6). (We recommend an
application of "Rectorseal" to threads to make a
secure fit.)
5. Repeat the above process if the first attempt
does not stop the valve from leaking.
'(Seating tool may be obtained from the factory.)
THE STEAM PRESSURE GAUGE ASSEMBLY
To remove the complete steam pressure gauge
assembly, it will first be necessary to remove the side
panel. The steam pressure gauge may then be
detached by removing item (2) and then removing the
two nuts which hold the pressure gauge bracket in
place. The guage is then removed from the front of
cooker. To reassemble, reverse the above procedure.
ITEM PART NO. DESCRIPTION
1 90-8693 3/16 "0. D. Tubing (Model A-1)
15-7054 3/16 " 0. D. Tubing (Model A)
2 10-4370 Brass Nut for Compression Fitting
3 10-4371
Brass Sleeve for 3/16 "
Compression Fitting
4 10-4748 0-30 No. Pressure Gauge
5 10-3360
1/8 "IPS Male x 3/ 16 O.D. Tube
Elbow
5110
Page 18
THE CONTROL BOX ASSEMBLY
The control box assembly is a device which
converts an electrical impulse into a mechanical
action. The mechanical action, stemming from the
sudden release of a spring loaded system of
levers, shuts off the steam supply, exhausts the
steam from the cooking chamber, switches off a
pilot light, and sets off a buzzer. This action is
preset manually, with the simple action of setting
the timer to the cooking timer required and pulling
out the operating handle into the "on" position.
The illustrations of "on" and "off" positions will
serve to familiarize you with the proper
relationship of the inner parts of the control box
assembly.
HOW IT WORKS
When in "off" position; the valve will be closed restricting the steam from passing into the cooking
compartment, the pilot light will be off, the buzzer
inactive and the solenoid de-energized.
When the timer is set for the required cooking time
and the operating handle is pulled to the "on"
position; the valve will be opened to allow steam
into the cooking compartment, the pilot light will
light up, signifying that cooking is taking place, the
buzzer and solenoid will still be de-energized.
When the cycle on the timer clock has been
completed, a flow of current will energize the solenoid
forcing the solenoid push rod to lift and disengage the
operating handle. The operating handle now freed
from the bumper and stop bar will spring back to the
"off" position. The innermost micro-switch, released
from the pressure of the pin of the operating handle
will break the circuit to the solenoid, and the pilot light
and the solenoid both will become inactive. The
nearer solenoid having been pushed into a locked
position under the buzzer lock will remain in contact
operating the buzzer until released by pushing the
buzzer release knob by hand.
TROUBLE -TEST AND REMEDIES
If the operating handle will not lock in the "on"
position:
Check first that timer has been set. Check that
the stop bar is properly secured.
Check that solenoid and bracket is pos itioned
properly.
If the operating handle fails to retract to "off" position:
Check the valve synchronizer spring for
looseness. Check all linkage for binding or
loosened parts.
Check switch on timer for continuity.
Check micro switch for bent arm.
Check for blown fuse and then for defective
wiring or defective solenoid.
5111
Page 19
Valve
5
Ib. -
enamel
SUGGESTED STEAM CONNECTIONS
The illustration shows a recommended system of installation
which provides: a pressure gauge to measure the pressure
input at the source of supply, a globe valve for emergency
shut-off, a ball-float trap to prevent dirt and water from
entering the cooking units, and a pres sure regulating valve to
reduce and regulate steam pres sures for delivery.
End of Cooking Cycle Timer at zero, Control Arm in
unlocked position. Light, Solenoid & Buzzer deenergized. (Buzzer silenced by reset button on
switch.)
5114
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