Blodgett MT1828E Service Manual

MT1828

CONVEYOR OVEN

SERVICE AND REPAIR MANUAL

BLODGETT OVEN COMPANY

www.blodgettcorp.com

50 Lakeside Avenue, Box 586, Burlington, Vermont 05402 USA Telephone (802) 658Ć6600 Fax: (802)864Ć0183

PN M8560 Rev C (6/01)

Duplication of the information in this manual is prohibited without the consent of the Blodgett Service Department.

 2001 - G.S. Blodgett Corporation All rights reserved.

TABLE OF CONTENTS

2. INTRODUCTION

Oven Specifications 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Ventilation Requirements 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Electrical Specifications 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Gas Specifications 3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3. OPERATION

Computer Controller 2-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Control Description 2-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Control Operation 2-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Programming Procedures 2-2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Display Information 2-2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Sequence of Operation 2-3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

MT1828G Domestic and General Export Ovens Internal Mount - M7296 Rev B 2-3. . . . . . .

MT1828G Domestic and General Export Ovens External Mount - M9776 Rev B 2-5. . . . . .

MT1828E Domestic and General Export Ovens - M6314 Rev C 2-7. . . . . . . . . . . . . . . . . . . .

MT1828G CE Ovens - M6462 Rev B 2-9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

MT1828E CE Ovens - M6453 Rev A 2-11. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4. CALIBRATION AND ADJUSTMENT

Convection Blower Motors 3-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

To check motor rotation 3-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

To check lowĆlimit 3-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Regulated Gas Pressure 3-2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Computer Control Configuration 3-3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Temperature Calibration 3-5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Belt Speed Calibration 3-6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Closed Loop System 3-6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Open Loop System 3-7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Motor Control Board 3-8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

5. ENHANCEMENTS

Burner 4-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Igniter and Flame Rods 4-4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

6. TROUBLESHOOTING

DC Drive System 5-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Computer Control System 5-2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Heating System 5-3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Convection System 5-5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

i

CHAPTER 1

INTRODUCTION

MT1828

OVEN SPECIFICATIONS

VENTILATION REQUIREMENTS

The hood should completely cover the unit with an
overhang of at least 6" (15 cm) on all sides not adjaĆ
cent to a wall. The distance from the floor to the
lower edge of the hood should not exceed 7' (2.1
m). The ventilation system should replace 80% of
the exhaust volume with fresh make up air.
TABLE 1 should be used as a guideline.

Single Double Triple

CFM 400Ć500 900Ć1000 1200Ć1500

M3/min 14 Ć 17 28Ć34 42Ć51

TABLE 1

L1

N

L2

ELECTRICAL SPECIFICATIONS

NOTE: Three Phase hookup is not permitted on

gas models.

Installations within the U.S.

The MT1828G requires a 15 Amp, 60HZ, 1F,
208Ć240VAC, 4 wire service consisting of L1, L2,
neutral and ground. See FIGURE 1. Use 90C wire
and size to National Electric or local codes.

The MT1828E is available in either 1F or 3F modĆ
els. Single phase models require a 60Hz,
208/240VAC, 3 wire service consisting of L1, L2
and ground. Three phase models require a 60Hz,
208/240VAC, 4 wire service consisting of L1, L2, L3
and ground. See FIGURE 1. Wiring from the power
source to any of these units must be a minimum of
#8 AWG copper stranded wire or larger for 3 phase
and #4 AWG for 1 phase.

120

120

208Ć240

OvenSupply

MT1828G

L1

L2

208/240

OvenSupply

L1

L2

L3

208/240

MT1828E Single Phase MT1828E Three Phase Delta System

FIGURE 1

OvenSupply

1

MT1828

Installations outside the U.S.

The MT1828G requires a 15 Amp, 50Hz, 1F, 240
VAC, 3 wire service consisting of L1, neutral and
ground. See FIGURE 2. Use 90C wire and size
wire according to local codes.

The MT1828E is available in either 1F or 3F modĆ
els. Single phase models require a 50 Hz,
220/240VAC, 3 wire service consisting of L1, L2
and ground. Three phase models are available in
either Delta or WYE configurations. Delta models
require 50Hz, 208/240VAC, 4 wire service consistĆ
ing of L1, L2, L3 and ground. WYE models require
50 Hz, 220/240 VAC, 5 wire service consisting of

L1

N

240

OvenSupply

MT1828G Export Installations

L1

L2

L3

208/240

OvenSupply

L1, L2, L3, neutral and ground. See FIGURE 2. Use

2

a minimum of 8.37 mm

copper stranded wire or

larger for 3 phase and 21.15 mm2 for 1 phase.

CE approved installations

The MT1828G requires 15 Amp, 50Hz, 1F, 230
VAC, 3 wire service consisting of L1, neutral and
ground. Connect exhaust fan connector 1 and 2.
See FIGURE 2. Use 90C wire and size according
to local codes.

The MT1828G requires 50 Hz, 3F, 230VAC, 5 wire
service consisting of L1, L2, L3, neutral and
ground. See FIGURE 2. Use 90C wire and size
according to local codes.

L1

L2

220/230/240

OvenSupply

MT1828E Single Phase Export Installations

L1

L2

L3

N

415/400*/380

415/400*/380

415/
400*/
380

240/
230*/
220

OvenSupply

MT1828E Three Phase Delta System

Export Installations

L3

L2

L1

N

Blodgett

Connector

N

L

Connector

L1

N

230

1
2

OvenSupply

MT1828G CE Approved Installations

FIGURE 2

* - CE Approved Installations

MT1828E Three Phase WYE System

Export and CE Installations

2Ć4Ć92

A1

Relay A

1

Fan

s

2

A2

21Air Pressure Regulator

Burner Control Solenoid

2

MT1828

GAS SPECIFICATIONS

GAS CONNECTIONS

Domestic and General Export installations

The gas line should be large enough to accommoĆ
date the peak demand of all the gas appliances.
TABLE 2 reflects a straight line, 50 foot run with no
coupling restrictions and no other appliances
drawing service. Gas line installations MUST conĆ
form to National Fuel Gas Code NFPA 54/ANSI
Z223.1 Sec. 1.4 (Latest Edition). TABLE 2 should
be used as a guideline only.

NOTE: For any pipe runs over 50 feet (15 m), conĆ

sult the factory.

CE approved installations

1. Connect the oven to the gas line with the propĆ
er type of gas according to Local and National
Installation Standards. See TABLE 2.

DOMESTIC AND GENERAL EXPORT

Natural Gas Propane Gas

Gas Line Sizing

GAS REQUIREMENTS

The firing rate for the MT1828G is 33,000 BTU/Hr.
(9.7 kW/Hr.)

NOTE: For natural gas meter sizing, consult your

local gas company to ensure that your meĆ
ter will provide the proper supply.

Installations within the U.S.

1. Add the total BTU's/hr of all the gas
appliances.

2. Convert BTU's to cubic ft/hr using the formula
Cu Ft/Hr = 1000 BTU/Hr for natural gas.

3. Size the meter accordingly.

Installations outside the U.S.

1. Add the total M3/min of all the appliances.

2. Size the meter accordingly.

Single

Double

Triple

Orifice Size #34 MTD #49 MTD

Incoming Gas Pressure W.C. kPa mbar W.C. kPa mbar

Static

Operational

Manifold Gas Pressure 3.5" 0.87 9 10" 2.49 25

CE APPROVED UNITS

Type of

Gas

G25 25 8 3,1 22,3 9,8 Nat. Gas

G20 20 8 2,7 22,3 9,8 Nat. Gas

G20/G25 20/25 Totally Inscrewed

G30 30/50 24 1,55 22,3 9,8 Butane

G31 30/37/50 24 1,7 22,3 9,8 Propane

Inlet

Pressure

mbars

Burner Pressure

Pressure Regulator

7"

5.5"

mbars

3/4" line

3/4" line

3/4" line

1.74

1.36

Injector

Diameter

3/4" line

3/4" line

3/4" line

17.4

13.7

Opening

mm

2,3 22,3 9,8 Nat. Gas

Air

mm

12.5"

11"

3.11

2.73

Standard Delivery

Value kW (HS)

31.1

27.4

TABLE 2

3

CHAPTER 2

OPERATION

MT1828

COMPUTER CONTROLLER

9

1

2

3

45678

FIGURE 1

CONTROL DESCRIPTION

1. DIGITAL DISPLAY - Displays the time, temĆ
perature and controller related information.

2. OVEN ON/OFF - Controls power to the oven.

3. NUMERIC KEYS - Used to enter numerical
data in the programming mode.

4. CLEAR KEY - Used to clear the display if an
error is made in the programming mode.

5. SET TEMP KEY - Used to view or program the
temperature setpoint.

6. ACT TEMP KEY - Used to view the current
oven temperature.

7. TIME KEY - Used to view or program the cook
time.

8. PROG/ENTER KEY - Used to enter and exit
the programming mode. Also used to lock in
programmed settings.

9. STATUS LAMPS - When lit indicate that the
fan or burners are operating.

This oven, supplied with remote control, is
equipped with an emergency shut down
switch. Should you need to stop the belt,
fans, or heat press the emergency switch.

Do not use the emergency switch as a
GENERAL on/off switch!

CONTROL OPERATION

To turn the oven on:

1. Press and hold the ON/OFF key (2). The disĆ
play reads OFF when the oven is idle.

2. The display flashes WAIT  LOW  SET  TIME 

mmss.

3. The FAN and HEAT status lamps (9) light. The
fans begin to run. The heat rises to the proĆ
grammed temperature. The conveyor belt
travels at the programmed speed.

To view the cook time setting:

1. Press the TIME key (7). The LED on the key
lights and the display flashes SET  TIME 

mmss.

To display the actual oven temperature:

1. Press the ACT TEMP key (6). The LED on the
key lights and the display reads ACTUAL 

nnnnF.

To view the temperature set point:

1. Press the SET TEMP key (5). The LED on the
key lights and the display flashes SET  TEMP

 nnnnF.

To turn the oven off:

1. Press the ON/OFF key (2). The blower moĆ
tor(s) continue to run regardless of the controlĆ
ler status until the temperature drops below
180F (82C).

2-1

OPERATION

PROGRAMMING PROCEDURES

Programming the Cook Time:

1. Press the PROGRAM/ENTER key (8).

2. Press the TIME key (7). The display reads

PROGĆ?  SET  TIMEĆ?  _ _ _ _.

3. Use the NUMERIC keys (3) to enter the desired
cook time. The display will read the numbers
as they are entered. If an error is made, press
the CLEAR key (4) and reĆenter the number.

4. Press the PROGRAM/ENTER key (8) a second
time to lockĆin the new time. The new cook time
will be stored in the computer's memory.

Programming the Temperature:

1. Press the PROGRAM/ENTER key (8).

2. Press the SET TEMP key (5). The display reads

PROGĆ?  SET  TEMPĆ?  _ _ _ _F.

3. Use the NUMERIC keys (3) to enter the desired
temperature set point. The control displays the
numbers as they are entered. If an error is
made, press the CLEAR key (4) and reĆenter
the number.

4. Press the PROGRAM/ENTER key (8) a second
time to lockĆin the new temperature. The new
temperature setpoint will be stored in the comĆ
puter's memory.

Operation at the Programmed Settings:

1. Press and hold the ON/OFF key (2).

DISPLAY INFORMATION

 WAIT  LOW - indicates that the present oven

temperature is lower than the set point temperĆ
ature. When the oven reaches the set point
temperature the display changes to READY.

 READY - indicates that the oven is ready to acĆ

cept product.

 SET  TIME  mmss - indicates the current

cook time setting.

 HIGH  TIME - indicates that the temperature

is well above the set point. This usually occurs
when moving from a higher āto a lower temperaĆ
ture. Wait until the display reads ready before
loading product.

 HIGH  TEMP  LIMIT - indicates that the oven

temperature exceeds the high limit from the
2nd level program. The Over Temperature
Alarm buzzer will sound. Shut the oven off and
wait for the unit to cool down.

 MTR  SPD - indicates speed of the motor

does not match the set point.

 MOTOR - indicates the computer is not reĆ

ceiving the signal back from the pickup.

 HI  TEMP  MOTOR - N.A.

 PROBE  OPEN  PROBE  SHORT - indicates

that the temperature sensor has failed. The
Alarm buzzer sounds. Shut the oven off and
contact a service representative.

2. The FAN and HEAT status lamps (9) light. The
fans begin to run. The heat rises to the temperĆ
ature setting stored in the computer's memory.
The conveyor belt begins to travel at the timed
speed stored in memory.

3. The display will flash WAIT  LOW  SET  TIME

 mmss until the programmed bake temperaĆ

ture is reached. The HEAT lamp (9) will remain
lit until the oven reaches the temperature set
point.

4. The display reads READY and the HEAT lamp
(9) goes out.

5. The oven is now ready to accept product.

6. Press and hold the ON/OFF key (2) to turn the
oven off. The fans continue to run while the
oven cools to a safe temperature.

2-2

MT1828

SEQUENCE OF OPERATION

MT1828G DOMESTIC AND GENERAL EXPORT OVENS INTERNAL MOUNT - M7296
REV B

COMPONENT REFERENCE

NOTE: Refer to FIGURE 2 for component locaĆ

tions.

1. BLOWER RELAY

2. BELT STOP RELAY

3. HEAT RELAY

4. MOTOR CONTACTOR

5. SINGLE POLE DOUBLE THROW THERMAL
SWITCH

6. MOTOR CONTROL BOARD

7. SINGLE POLE SINGLE THROW THERMAL
SWITCH

8. RESETABLE HI LIMIT

9. 115/24 VOLT TRANSFORMER

10. FLAME BLOWER

11. IGNITION CONTROL MODULE

12. COOKING COMPUTER

13. PRESSURE SWITCH

14. H.S.I.

15. BURNER VALVE

16. PROOF OF FLAME ROD

17. SINGLE POLE DOUBLE THROW THERMAL
SWITCH

18. CONVECTION BLOWERS

19. COOLING FANS

OPERATION

1. Apply power to the oven. Program time and
temperature into the computer (12). The blowĆ
er relay (1), belt stop relay (2) and heat relay (3)
close.

2. When the blower relay (1) closes, 110 V.A.C.
are sent to the coil of the motor contactor (4)
starting the convection blowers (18) and N.C.

terminal of a single pole double throw thermal
switch (5).

3. When the belt stop relay (2) closes, 110 V.A .C.
are sent to the motor control board (6) and the
single pole single throw thermal switch (7). If
this switch is closed, power goes to the resetĆ
able hi limit switch (8).

4. If the resetable hi limit switch is closed power
goes to the 115/24 volt transformer (9) located
in the box mounted on the flame blower (10).
The flame blower starts.

5. The secondary side of the transformer (9)
sends 24 volts to L1 of the ignition control modĆ
ule (11) and one side of the heat relay (3). If the
computer (12) closes the heat relay, the 24
volts will go to the pressure switch (13).

6. If the pressure switch is closed, a circuit will be
completed back to the ignition module (11).

7. The ignition module initiates its firing sequence
by sending power to the H.S.I. (14). After a
warm up period both solenoids on the burner
valve (15) open allowing gas to enter for igniĆ
tion. If no flame is sensed by the proof of flame
rod (16) the system shuts down.

NOTE: Some ignition control modules may try

to refire up to 3 times. However, there
will be a longer warm up period beĆ
tween each attempt at ignition.

8. The thermal switches (5 and 17) toggle from
common to N.O. only when they reach the temĆ
perature stated on the back of the switch.

9. The convection blowers (18) receive their powĆ
er from the motor contactor (4) only.

10. The cooling fans (19) come on only when the
motor contactor (4) is energized or if the therĆ
mal switches (5 and 17) have toggled.

2-3

OPERATION

9

8

7

13

10

16

14

15

18

18

4

11

6

17

19

5

19

19

19

19

1 2 3

12

FIGURE 2

2-4

MT1828

MT1828G DOMESTIC AND GENERAL EXPORT OVENS EXTERNAL MOUNT - M9776
REV B

COMPONENT REFERENCE

NOTE: Refer to FIGURE 2 for component locaĆ

tions.

1. BLOWER RELAY

2. BELT STOP RELAY

3. HEAT RELAY

4. MOTOR CONTACTOR

5. SINGLE POLE DOUBLE THROW THERMAL
SWITCH

6. MOTOR CONTROL BOARD

7. SINGLE POLE SINGLE THROW THERMAL
SWITCH

8. RESETABLE HI LIMIT

9. 115/24 VOLT TRANSFORMER

10. FLAME BLOWER

11. IGNITION CONTROL MODULE

12. COOKING COMPUTER

13. PRESSURE SWITCH

14. H.S.I.

15. BURNER VALVE

16. PROOF OF FLAME ROD

17. SINGLE POLE DOUBLE THROW THERMAL
SWITCH

18. CONVECTION BLOWERS

19. COOLING FANS

OPERATION

1. Apply power to the oven. Program time and
temperature into the computer (12). The blowĆ
er relay (1), belt stop relay (2) and heat relay (3)
close.

2. When the blower relay (1) closes, 110 V.A.C.
are sent to the coil of the motor contactor (4)
starting the convection blowers (18). When the

motor contactor closes, power is also applied
to the NIC terminal of a single pole double
throw thermal switch (5).

3. When the belt stop relay (2) closes, 110 V.A .C.
are sent to the motor control board (6) and a
single pole single throw thermal switch (7). If
this switch is closed, power goes to the resetĆ
able hi limit switch (8).

4. If the resetable hi limit switch is closed power
goes to the 115/24 volt transformer (9) located
in the box mounted on the flame blower (10).
The flame blower starts.

5. The secondary side of the transformer (9)
sends 24 volts to one side of the heat relay (3).
If the computer (12) closes the heat relay, the
24 volts will go to the pressure switch (13).

6. If the pressure switch is closed, a circuit will be
completed to the ignition module (11).

7. The ignition module initiates its firing sequence
by starting to spark at the spark electrode (14)
and opening both solenoid valves on the burnĆ
er valve (15) allowing gas to enter for ignition.
If no flame is sensed by the proof of flame rod
(16) the system shuts down.

NOTE: Some ignition control modules may try

to refire up to 3 times. However, there
will be a longer interpurge period beĆ
tween each attempt at ignition.

8. The thermal switch (17) toggles from common
to N.O. only when it reaches the temperature
stated on the back of the switch.

9. The convection blowers (18) receive their powĆ
er from the motor contactor (4) only.

10. The cooling fans (19) come on only when the
motor contactor (4) is energized or if the therĆ
mal switch (17) has toggled.

2-5

OPERATION

9

8

7

13

3

10

16

14

18

11

4

6

2

17

1

19

12

FIGURE 3

2-6