Market Forge 4292 Service Manual

SERVICE & PARTS MANUAL

Models:

4200 ELECTRIC COMPACT CONVECTION OVEN

4200
4292

35 Garvey Street, Everett, MA 02149

Tel. [phone], Telex 94-9414, Cable MAFORCO
Facsimile # 617-387-4456
Form Number S-2296B 7/84 Printed in U.S.A.

TABLE OF CONTENTS

4.2.7

Motor Removal

4-2

Electrical Data

60

Hz

2-4

5.2

Trouble

-

Shooting Guide

5-1

SECTION 1 INTRODUCTION

1.1 Description 1-1

1.2 Oven Components 1-1

1.3 Basic Functioning 1-1

1.4 Service 1-1

4.2.3 Oven Liner Gasket Removal 4-1

4.2.4 Gasket Replacement 4-1

4.2.5 Blower Wheel Removal 4-1

4.2.6 Blower Wheel Replacement 4-1

SECTION 2 INSTALLATION

2.1 Receiving 2-1

2.2 Assembly 2-1

2.2.1 Vent Box Attachment 2-1

2.2.2 Single Oven on 4"' 102mm Legs 2-1

2.2.3 Single Oven on 27" 686mm Legs
with shelf 2-1

2.2.4 Stacked Ovens on 18" 457mm Legs
with shelf 2-2

2.3 Electrical Connection 2-2

2.4 Oven Checkout and Adjustments 2-3

2.4.1 Door Adjustment 2-3

2.4.2 Thermostat Calibration 2-3

2.4.3 To Calibrate Electronic Thermostat 2-3
Wiring Diagram, Schematic and

Wiring Diagram, Schematic and

Electrical Data 50 Hz

SECTION 3 OPERATION

3.1 Principle of Operation 3-1

3.2 Controls 3-1

3.3 Preheating 3-1

3.4 Operation 3-1

SECTION 4 MAINTENANCE

4.1 Cleaning 4-1

4.2 Removal & Replaceme nt of Parts 4-1

4.2.1 Door Removal 4-1

4.2.2 Door Replacement

2-5

4-1

4.2.8 Motor Replacement 4-2

4.2.9 Switch Removal 4-2

4.2.10 Switch Replacement 4-2

4.2.11 Contactor and Fuse Holder
Removal 4-2

4.2.12 Contactor and Fuse Holder
Replacement 4-2

4.2.13 Thermostat Removal 4-2

4.2.14 Thermostat Replacement 4-3

4.2.15 Heater Element Removal 4-3

4.2.16 Heater Element Replacement 4-3

4.2.17 Door Interlock Switch Bracket
Removal 4-3

4.2.18 Door Interlock Switch Bracket
Replacement 4-3

SECTION 5 TROUBLE-SHOOTING

5.1 General

Table 5-1 Trouble Shooting Guide 5-1
Table 5-2 Electrical Fault Isolation 5-2

5.3 Wiring 5-2
Table 5-3 Trouble-Shooting Guide For

Electronic Thermostat 5-3

SECTION 6 ILLUSTRATED PARTS LIST

6.1 General 6-1

6.2 Ordering Information 6-1
Illustrated Parts List 6-2 to 6-7

5-1

4200 Compact Convection Oven

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 Model 4200 Electric Compact Convection

Oven. Also included are parts lists, in which each replaceable part is identified and shown in an accompanying

1.1 DESCRIPTION
The Market Forge Model 4200 Electric Compact
Convection Oven is an electrically powered
convection oven designed to achieve high-volume
cooking with a minimum of power consumption. The
unit consists of a heavily insulated cooking
compartment fitted with a two-speed convector
blower and heated by electric elements. All oven
controls are located on a panel on the right front of
the oven as seen from the front.

1.2 OVEN COMPONENTS
The major assemblies of the model 4200 are the
stainless steel and flat black painted steel cabinet
enclosure, door with window, porcelain cooking
compartment with nine-position shelf supports,
heating element and contactor assembly, and control
panel assembly. Controls and indicators include the
thermostat, main power switch, blower speed switch,
cool down switch, elements on indicator light, 60­minute timer, and two 15 amp fuses. The oven is
available in variety of mounting configurations: 4"
102mm high legs, 27" 686mm legs with shelf, or
stacked on top of another Model 4200 with the
bottom unit on 18" 457mm stainless steel legs with
shelf.

1.3 BASIC FUNCTIONING
The Model 4200 becomes operational when the
power switch is placed in the ON position, door is

1-1

illustration.

closed, and thermostat set. Contactors located in the
control section close the circuit to heating elements
located at the right of the cooking chamber. When
the chamber reaches the preset temperature, the
thermostat contacts open, causing the contactors to
interrupt the circuit to the heating elements. When
the temperature in the chamber drops enough to
close the thermostat contacts, the circuit closes
again. Any number of such cycles might occur
during the cooking time, indicated by the element
indicator light coming on and off.

1.4 SERVICE
Required service, both preventive and corrective, is
explained in section 5. 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 Company
35 Garvey Street
Everett, MA 02149
[phone]

The model and serial number must be referenced
when corresponding with Market Forge.The data
plate with serial number is located on the right of the
bottom front trim ledge.

ONE YEAR WARRANTY

We warrant that Market Forge cooking equipment will be free from defects in material and factory workmanship for
a period of one year from the EFFECTIVE WARRANTY DATE, which shall be the date the equipment is placed in
service or 15 months from date of shipment from our factory, whichever comes first Providing the equipment is
unaltered, has been properly installed, maintained and operated, we will repair, or replace, at our option, FOB
Everett, Massachusetts, that part of any such equipment that becomes defective due to defects in material and/or
factory workmanship during the applicable warranty period, subject to the following limitations

Market Forge will replace, repair, or adjust at no cost any part of all equipment other than portable equipment,
which becomes defective due to material or factory workmanship within ninety (90) days of the Effective Warranty
Date Any labor required for any such repair, replacement or adjustment after ninety (90) days shall be paid by the
user or dealer, unless our extended labor warranty contract has also been purchased to cover this particular
equipment

With respect to PORTABLE COOKING EQUIPMENT, so designated in this price list, Market Forge will replace,
repair, or adjust at no cost any part which bec omes defective due to material or factory workmanship within one (1)
year of the Effective Warranty Date. providing the portable equipment is taken or shipped to the closest authorized
service agency, transportation charges prepaid Proof of purchase shall be provided upon request of the service
representative

With respect to STEAM BOILER SHELLS only. there is an additional four (4) year warranty limited to the
replacement of such shells Whenever we replace a steam boiler shell after one (1) year from the Effective
Warranty Date, the user shall pay a pro-rata share of the then selling price therof based on the number of months
elapsed from the Effective Warranty Date

THIS WARRANTY IS LIMITED TO COOKING EQUIPMENT INSTALLED WITHIN THE 48 CONTINENTAL
UNITED STATES AND CANADA IN ALASKA, HAWAII, AND ELSEWHERE OUTSIDE CONTINENTAL US AND
CANADA, THIS WARRANTY IS LIMITED TO THE REPLACEMENT OF PARTS ONLY

THERE ARE NO WARRANTIES, EXPRESSED OR IMPLIED, MADE BY MARKET FORGE FOR ITS COOKING
EQUIPMENT. EXCEPT THIS WARRANTY, WHICH IS EXPRESSLY IN LIEU OF ANY OTHER WARRANTIES,
EXPRESSED OR IMPLIED, INCLUDING ANY IMPLIED WARRANTY OR MERCHANTABILITY OR FITNESS FOR
A PARTICULAR PURPOSE AND IN LIEU OF ALL OTHER OBLIGATIONS OR LIABILITY ON THE PART OF
MARKET FORGE. INCLUDING LIABILITY FOR INCIDENTAL OR CONSEQUENTIAL DAMAGES OR FOR LOSS
OF PROFITS OR GOODWILL. NO OTHER WARRANTIES ARE AUTHORIZED ON BEHALF OF MARKET
FORGE MARKET FORGE. COOKING EQUIPMENT IS NOT DESIGNED FOR PERSONAL, FAMILY OR
HOUSEHOLD PURPOSES AND ITS SALE FOR SUCH PURPOSES IS NOT INTENDED, BUT IN THE EVENT
THAT OUR COOKING EQUIPMENT IS SO USED. THEN THIS WARRANTY SHALL NOT APPLY AND THE
EQUIPMENT SHALL BE SOLD AS IS, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
INCLUDING ANY WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.

EXTENDED LABOR WARRANTY AND MECHANICAL START-UP

The very great majority of all warranty service problems become apparent within the first 90 days of use However,
some people prefer to have labor coverage as well as replacement parts coverage beyond that period. This
Extended Labor Warranty is available at extra cost in Continental U S and Canada which provides an additional
nine months labor coverage following the standard three month labor coverage from the effective warranty date.
The cost of this Extended Labor Warranty is 2% of the cost of the equipment covered.

If the Extended Labor Warranty was purchased by your dealer to cover your equipment, then we provided the
dealer with written acknowledgement of it when we delivered the equipment. He was, in turn, to give you a copy of
this Extended Labor Warranty form When service is performed, please show this to the service mechanic to avoid
confusion Extended Labor Warranty has also been recorded at our factory.

Providing the Extended Labor Warranty has been purchased, and subject to availability of the local authorized
factory service agency, a mechanical start-up to insure that the equipment has been properly installed and is
operating properly can be purchased for an additional 2% of the cost of the equipment

SECTION 2 INSTALLATION

Figure

2-2

Table

2-1

2.1 RECEIVING

1. Examine shipment for external and internal
damage and completeness. Transport crated
oven through building, to installation area before
unpacking.

2. Report any damage or shortages to carrier and
Market Forge immediately.

3. DO NOT AT ANY TIME LAY THE OVEN DOWN
ON ITS TOP, RIGHT SIDE, OR FRONT. TO
DO SO MAY DAMAGE THE EQUIPMENT AND
VOID THE WARRANTY.

2.2 ASSEMBLY

2.2.1 Vent Box Attachment

1. Remove steam vent box and packet of screws
from inside oven and attach vent box to back of
oven over vent opening using five #8 sheet metal
screws. (Fig. 2-1 No. 1)

3. Insert leg tops (Fig. 2-2 No. 2) through holes in
angle iron frame (Fig. 2-2 No. 4) into weldnuts in
bottom of oven.

4. Screw leg tops (Fig. 2-2 No. 2) into weldnuts by
turning leg and top assemblies.

5. Raise shelf (Fig. 2-2 No. 1) to desired height and
tighten set screws in shelf corners.

Figure 2-1

2.2.2 Single Oven on 4" (102mm) Legs

Fasten legs to the weld nuts located on bottom panel
of oven. The hex foot on the leg is adjustable.

2.2.3 Single Oven on 27" (686mm) Legs with Shelf

1. Insert legs (Fig. 2-2 No. 3) through holes in shelf
(Fig. 2-2 No. 1). Do not tighten set screws in
corners of shelf.

2. Screw leg tops (Fig. 2-2 No. 2) onto legs (Fig. 2­2 No. 3).

Item Part No. Description Qty.

1 99-6180 Solid Shelf, ST. ST. 1
2 A10-0635 Leg Top 4
3 A10-0634 Floor Leg, 27" High 4
4 D99-6183 Shelf, 4200 Elec. Oven 1

2.2.4 Stacked Ovens on 18" (457mm) Legs with

Shelf

1. Insert legs (Fig. 2-3 No. 6) through holes in shelf
(Fig. 2-3 No. 5). Do not tighten set screws in
corners of shelf.

2. Screw leg tops (Fig. 2-3 No. 7) onto legs (Fig. 2-3
No. 6).

3. Insert leg tops (Fig. 2-3 No. 7) through holes in
angle iron frame (Fig. 2-3 No. 8) into weldnuts in
bottom of oven.

4. Screw leg tops (Fig. 2-3 No. 7) into weldnuts by
turning leg and leg top assemblies.

5. Raise shelf (Fig. 2-3 No. 5) to desired height and
tighten set screws in shelf corners.

6. Remove access panel from right side of both
ovens.

7. Remove knockouts from the top of the bottom
oven and from the bottom of the top oven.

8. Place upper oven on top of lower oven and line up
the holes in the top of the lower oven with the
holes in the bottom of the upper oven.

9. Fasten ovens together with the washer (Fig. 2-3
No. 3) and bolt (Fig. 2-3 No. 2) inserted up thru top
of lower oven into bottom of upper oven using the
existing weld nut to fasten the rear and the nut
provided with the stacking kit (Fig. 2-3 No. 4) to
fasten the front.

10. Remove the existing vent covers from each oven
and replace with the vent riser (Fig. 2-3 No. 1)
using the fasteners just removed.

2.3 ELECTRICAL CONNECTION

1. Read data plate located on top surface of right side
of bottom trim just below control panel before
connecting electrical supply to oven. Make sure
electrical supply is the same voltage, phase, and
frequency called for on data plate.

2. All ovens are shipped 3 phase and may be
converted to single phase as per alternate 1 phase
wiring diagram.

3. Feed supply through opening in rear of oven (Fig.
2-1 No. 2) and connect supply wires to terminal
block behind control panel.

4. Wiring diagram label is located on control

bracket, accessible by opening control
panel.
NOTE: Improper connection to power supply or
connection to power supply other than that designated
on data plate will void the warranty.

Figure 2-3

Item Part No. Description Qty.

1 C99-6178 Vent Riser 1
2 10-2564

3 10-2411 Plain Washer, 3/4 2
4 10-2320
5 99-6180 Solid Shelf, ST. ST. (Ref. Dwg.

6 A09-5271 Floor Leg, 18" High 4
7 A10-0635 Leg Top 4
8 D99-6183 Shelf, 4200 Elec. Oven 1

Hex Bolt, 3/4-10 x 3" Long

Hex Nut, 3/4-10

C25-2624) 1

Table 2-2

2

1

2.4 OVEN CHECKOUT AND ADJUSTMENTS

2.4.1 Door Adjustment

The door was properly adjusted at the factory, if door
does not open or close properly adjust the ball plunger
catch as follows:

1. Remove adjusting wrench from back of manual
and insert in notches on sides of ball plunger.

2. Loosen jam nut with wrench.

3. Turn adjusting wrench left or right until ball
plunger engages in door striker plate for best
operation.

4. Tighten jam nut with wrench while adjusting
wrench is still engaged in notches.

5. Return adjusting wrench to back of manual.

2.4.2 Thermostat Calibration
The thermostat is a device which automatically limits
heat input at or below the dial setting.

Before attempting to calibrate thermostat, make sure
that the thermostat is the cause of problems
experienced. Check for improper electrical service,
incorrect mixes over and under proofing, incorrect
temperatures, and warping pans.

Thermostats are calibrated and sealed by the original
manufacturer before leaving their plant. Only a
qualified service person should make calibration
adjustments, if they become necessary.

2.4.3 To Calibrate Electronic Thermostat

1. Set oven thermostat knob at 350° F.

2. Allow oven to preheat to 350° F.

3. Observe temperature with digital thermometer.

4. If temperature goes above 350° F turn setpot labelled
HI (on circuit board) counter clockwise. 1/4 turn
should be sufficient.

5. Allow time for oven temperature to drop, then
recheck temperature.

6. If temperature is below 350° F turn setpot labelled HI
(on circuit board) clockwise. 1/4 turn should be
sufficient.

7. Repeat steps 4 to 7 until oven temperature stabilizes
at 350° +5°F.

8. Apply Glyptol or Duco Cement to setpot to prevent
rotation.

Figure 2-4