Market Forge 3500-D Service Manual
SERVICE & PARTS MANUAL
Models:
Pressureless Steam Cooker
3500
3550
MARKET FORGE CANADA LTD.
Mississauga, Ontario, Canada
Form No. S-2196 4/79 Printed in U.S.A.
TABLE OF CONTENTS
1.2 Basic Fu
nctioning
1-1 5.2 Trouble
-
Shooting Guide
5-1
5.4 Electrical Trouble
-
Shooting
2.1 Assembly
2-1 5.4.1 Incoming Power
5-3 2.2 Setting In Place
2-1 5.4.2 Electrical Inspection
5-3
2.4 Installation Check
-
Out 2-1 5.4.4 15-MINUTE Timer
5-5
2.4.1 Initial Control Settings
2-1 5.4.5 60-MINUTE Timer
5-5
2.4.2 Cooker
Check
-
Out 2-1 5.4.6 Door I
nterlock Switch
5-5 2.4.3 Shut-Down Procedure
2-2 5.4.7 Steam Solenoid Valves
5-5
5.4.8 Indicator Lights
5-5
SECTION
3
OPERATION
5.4.9 Cooking Compartment Thermostat
3.2 Operating
Procedures
3-1 5.4.1.0
Buzzer
5-6
3.2.1 Steam Source Operation
3-1 5.4.1.1
Cold Water Condenser Circuit
5-6
3.2.2 Preheating
3-1 5.4.1.2
Wiring
5-6
3.2.3 Cooking
3-1
3.2.4 Shut-Down Procedure
3-1 SECTION
6
MAINTENANCE
3.3 Cleani
ng
3-2 6.1 General
6-1
SECTION
4
PRINCIPLES OF OPERATION
6.2.1 Door Disassembly and Cleaning
6-1
4.2 Plumbing Circuits
4-1 6.2.3 Cooking Compartment Cleaning
6-1
4.2.1 Steam Inlet Line
4-1 6.3 Repair and Replacement
6-2 4.2.2 Steam Exhaust and Drain Lines
4-1 6.3.1 Door Assembly
6-2
4.2.3 Steam Exhaust Condensing System
4-1 6.3.2 Exterior Panel Removal
6-2
4.2.4 Pressure Safety Valve
4-2 6.3.3 Steam and W
ater Solenoid Valve
4.3 Electrical Circuits
4-2
Replacement
6-2
4.3.1 Control Circuit Components
4-3 6.4 Door Adjustment
6-3
6.4.1 Latch Adjustment
6-3
7.2 Ordering Information
7-1
Paragraph Page Paragraph Page
SECTION 1 INTRODUCTION SECTION 5 TROUBLE-SHOOTING
1.1 Description 1-1 5.1 General 5-1
SECTION 2 INSTALLATION
3.1 Operating Controls and Indicators 3-1
Procedures 5-2
Switch 5-6
4.1 General 4-1 6.2.2 Door Latch Lubrication 6-1
6.4.2 Door Tension Adjustment 6-3
SECTION 7 ILLUSTRATED PARTS LIST
7.1 General 7-1
LIST OF ILLUSTRATIONS
Figure
3-2 Pan Support Removal
3-3 6-2 Control Panel Removal
6-2 6-3 Plumbing and Interior View
6-3
SECT ION
4
PRINCIPLES OF OPERATION
6-4 Latch Adjustment
6-3
4-1 Pictorial Diagram
— Steam
&
Water
Circuits
4-2 SE
CTION
7
ILLUSTRATED PARTS LIST
4-2 Pictorial Diagram
— Electrical
7-1 Cabinet Assembly
7-2
Circuits
4-3 7-2 Door Assembly
7-4 7-3 Plumbing Assembly
7-6 SECT ION
5
TROUBLE
-
SHOOTING
7-4 Control Panel
7-8
5-1 Wiring Diagram, Model
3500
5-4 5-2 Schematic Diagram, Model
3500
5-7
3-1
Controls and Indicators
3-3 5-1 General Trouble
-
Shooting Guide
5-1
SECT ION 3 OPERATION
3-1 Controls & Indicators 3-2 6-1 Inner Door Removal 6-1
Page Figure Page
SECTION 6 MAINTENANCE
LIST OF TABLES
Table Page Table
SECTION 3 OPERATION SECTION 5 TROUBLE-SHOOTING
5-2 Electrical Fault Isolation Guide 5-3
Page
SECTION 1 INTRODUCTION
This service and parts manual contains general information, installation, operation, principles of operation,
trouble-shooting and maintenance information for the Market Forge 3500 and 3550 Pressureless Steam
Cookers. Also included is a parts list in which each replaceable part is identified and shown in an
accompanying exploded view.
1.1 DESCRIPTION
The Model 3500 is a pressureless steam cooker
consisting of two independently controlled
compartments enclosed in a single cabinet. The
model 3550 includes a single compartment. Each
compartment is equipped with a separate two-piece
door with inner gasket plate isolated from the exterior
surface. Door latches operate by cam action for
positive sealing of inner door in one continuous hand
motion. 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 either 15-minute precision timed cooking
or 60-minute long duration cooking.
A separate steam source required for operation of
the Pressureless Cooker is normally purchased with
it, in which case the cooker is factory mounted with
all steam, drain, cold water and electrical interconnections completed. Model 3500/Boiler and 3550/
Boiler configurations with the cookers on 24-inch
wide cabinet bases containing electrically powered
steam boilers (model suffix E)are on the cover. Other
applications include the 3500 or 3550 Cooker on a
gas-fired boiler (model suffix G), a steam coil boiler
(model suffix SC), or a cabinet containing steam and
drain controls for direct connection to a remotely
located boiler (model suffix D). The Model 3500 may
also be mounted on larger boiler cabinets or be combined with other cooking equipment. Model 3550
utilizes the same boiler cabinets, designated by the
same suffixes as for the 3500.
1-1 S-2196
1.2 BASIC FUNCTIONING
The Model 3500 may be operated with only one
compartment in use, or, both may be used
simultaneously (The 3550 has only one
compartment). Each compartment is equipped with
identical controls allowing selection of either 15MINUTE TIMER or 60-MINUTE TIMER operation by
setting a two-position switch. The cooker becomes
operational when the selector switch is set to either
timer position, the timer is set at the desired cooking
time, and the compartment door is closed. The timer
indicator light comes on and the steam solenoid valve
opens allowing steam to flow into the compartment
through a slotted steam standpipe.
When steam flowing inside the compartment has
raised the interior temperature to 212°F, the contacts
of a thermostatic switch automatically close,
completing the circuit to the timer motor and starting
the 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.
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 boiler drain to condense the
steam to water prior to discharge into the boiler drain.
PRESSURELESS STEAM COOKER
1.3 SERVICE
Required service, both preventive and corrective,
is explained in Section 6. Should repairs be
required, a network of authorized agencies is
available to assist with prompt service. A current
Directory of Authorized Service Agencies may be
obtained by contacting:
Product Service Department
Market Forge
35 Garvey Street
Everett, Massachusetts 02149
Product Service Department
Market Forge Canada, Ltd.
1375 Aimco Blvd., Unit 5
Mississauga, Ontario,Canada L4W 1B5
Telephone: (416) 621-9252
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.
Telephone: (617) 387-4100
S-2196
SECTION 2 INSTALLATION
2-1
S-2196
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 which 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 on studs located
inside the cooking compartment.
4. Attach panels to lower cabinet. Detailed
instructions are enclosed with the panels.
2.2 SETTING IN PLACE
If possible a location should be selected under an
exhaust hood which will remove small amounts of water
vapor emitted when the cooker doors are opened. 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 are required to the cooker. 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 INSTALLATION CHECK-OUT
After the Cooker is completely assembled and all
mechanical connections made to its steam source (steam
boiler or direct steam connection plumbing), both steam
source and cooker must be given a thorough check-out
before being put into operation. Checkout procedures for
the cooker mounted on steam boilers of electric, gas and
steam coil utility or direct connected steam are given in
separate
Installation Instructions for each. Procedures for the
cooker only are included in subsection 2.4.2. 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.
2.4.1 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 timers for both compartments (Figure 3-1;
3, 4) are in the OFF position.
3. Cooker compartments are empty of all information
materials, pan supports are mounted in place and
doors are open.
2.4.2 Cooker Check-Out
The cooker check-out procedures are as follows:
1. Place selector switches (Figure 3-1, 2) in 15 MINUTE
TIMER (up) position.
2. Set 15-Minute Timers (3) to about the "4-minute"
position. Observe that indicator lights are off and
steam does not enter compartments.
3. Close cooker compartment doors being certain latch
handles (1) are in the down position and latches are
securely engaged. Observe that indicator lights turn
on and steam can be heard rushing int o the
compartment simultaneously with the door closing.
4. 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.
2-2 PRESSURELESS STEAM
COOKER
5. 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-
Pressureless Cooker except to check that all timer
dials (3, 4) 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.
minute" position at which a buzzer sounds. The
buzzer is silenced by turning the dial to the OFF
position.
6. Open cooking compartment doors and repeat
Steps 1 through 5 for the 60 MINUTE TIMER
(down) position of selector switch (1).
Before final check-off of the Cooker/Boiler
system for use in cooking, boiler start-up and
shut-down must be completed two more times
NOTE
to insure cleanliness and proper operation.
2.4.3 Shut-Down Procedure
No shut -down procedure is required for the
S-2196
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 3500 and 3550 are pressureless steam
cookers which defrost frozen foods and cook fresh
and defrosted foods. Each cooking compartment
permits selection of either short duration (0-15
minutes) timing or long duration (0-60 minutes)
cooking periods. Instructions for operation are
included in this section. Consult Test Kitchen
Bulletin #59 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 and latch
securely by pushing down on latch handle (1).
2. Place selector switch (2) for compartment(s) to
be used in 15-MINUTE TIMER (up) position.
3. Set 15-Minute Timer Dial (3) to "1-minute"
setting.
NOTE
Total elapsed preheating time equals the timer
setting plus a short delay period needed to
activate a thermostatic switch included in the
controls.
4. Turn off buzzer which sounds to indicate
cooking is complete by setting the 15-Minute
Timer Dial (3) to OFF position.
3.2.3 Cooking
Before loading the cooker, be sure compartment
is hot. See 3.2.2 for preheating instructions.
1. Slide pans of food into cooking compartment
pan supports.
2. Close cooking compartment door and push
down on latch handle (1) to engage.
3. Place Selector Switch (2) in required position:
a. 15-MINUTE TIMER—For short duration
timing.
b. 60-MINUTE TIMER— For long cooking
periods.
4. Set appropriate timer to the required cooking
time (see Test Kitchen Bulletin #59).
5. Turn off buzzer which sounds to indicate
cooking is complete by setting timer dial (3 or
4) to the OFF position.
6. Open door by lifting up on latch handle (1).
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 that both timer dials (3, 4)
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.)
3-1 S-2196
3-2 PRESSURELESS STEAM COOKER
3.3 CLEANING
After each period of daily operation (more
frequently as required to maintain cleanliness) the
cooker should be thoroughly cleaned by completing
the following steps:
1. Remove left and right side pan supports (Figure
3-2) by lifting up and off mounting studs. Wash
with detergent using a brush to clean drain
screen.
i-2196
Figure 3-1. Controls & Indicators
Rinse and set aside for reassembly.
2. Wash cooking compartment interior using
detergent and water. Rinse and dry thoroughly.
3. Replace pan supports in compartment and Leave
door open.
NOTE
Supports with drain screens must be installed on
left side of each compartment.
OPERATION
The cooking interval selector switch. Placed in up
Fig. 3-1 Ref. Description Function
TABLE 3-1
CONTROLS AND INDICATORS
(See Figure 3-1)
1 Latch Handle
Selector Switch
2
15-MINUTE TIMER/60-
MINUTE TIMER
3 15-Minute Timer
4 60-Minute Timer
5
6
Indicator Light (red)
15-Minute Timer
Indicator Light (red)
60-Minute Timer
Secures cooker door in closed position. Lift to
open.
position for 15-minute maximum timed interval;
down position for 60-minute maximum timed
period.
Controls short interval precision timed cooking
from 0 to 15 minutes.
Controls longer duration cooking times from 0 to
60 minutes.
Indicates when lit that cooker is in operation
controlled by 15-minute timer.
Indicates when lit that cooker is in operation
controlled by 60-minute timer.
7 Buzzer Signals end of cooking Period (not shown).
Figure 3-2. Pan Support Removal
SECTION 4 PRINCIPLES OF OPERATION
4.1 GENERAL
The 3500 Pressureless Steam Cooker consists of
two identical cooking compartments, one above the
other, in a single cabinet assembly. (Model 3550 has
only one compartment.) Each compartment is fitted
with independent electrically controlled steam circuits
and spring loaded, self-sealing doors with cam-action
latches. Compartments can be used separately (or
simultaneously for model 3500) for either of two timed
intervals— 15-minute maximum timing' or long
duration 60-minute maximum timing. The principles of
operation in this section include an explanation of
steam, steam condensing and electrical circuits and
their functioning for the Model 3500. Operation is
identical for the single compartment 3550.
4.2 PLUMBING CIRCUITS
The plumbing circuits consist of the piping, steam
solenoid valves, steam jet pipe, drain, cold water
condenser, and pressure safety relief valve required
to provide controlled steam application to the cooking
compartments. A simplified diagram of these circuits
for model 3500 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 a 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 either the 15-minute or 60-minute timers.
4-1 S-2196
4.2.1 Ste am Inlet Line
A steam supply line is plumbed from the boiler
output (or direct connected steam control), to a 1/2
inch "T" fitting connected to the input sides of both
steam inlet solenoid valves. At all times 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 a jet pipe
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
Steam exhaust and compartment drainage are
removed from the cooking compartments by a
separate line from each, connecting with the boiler (or
direct connected steam plumbing) drain system.
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.
4.2.3 Steam Exhaust Condensing System
The steam condensing system consists of the
identical, two-position, normally closed cold water
solenoid valves (one only in the model 3550) with
outlet sides connected into the exhaust plumbing for
each cooking compartment. A spray nozzle directs
cold water about the inside of the drain lines to
increase cold water contact with exhausted steam.
Valve inlet sides are connected to the cold water
supply line of the steam boiler (or direct connected
steam plumbing). The valves function simultaneously
(even though only one compartment may be in use)
and independently of other cooker controls, in
response to a thermostatic switch located at the
discharge opening of the boiler drain line. The switch
allows the valves to open at all times when the drain
temperature exceeds 193°F.
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