Lincoln Dual Technology Finisher 1922 User Manual

SERVICE MANUAL

DUAL TECHNOLOGY FINISHER

MODEL 1920 SERIES

Lincoln Foodservice Products, LLC

1111 North Hadley Road

Fort Wayne, Indiana 46804

United States of America

Phone : (800) 374-3004

U.S. Fax: (888) 790-8193 • Int’l Fax: (260) 436-0735

Technical Service Hot Line

(800) 678-9511

www.lincolnfp.com

DTFsvcman REV 1/5/07

SEQUENCE OF OPERATION

DUAL TECHNOLOGY FINISHER

1921 208VAC 60 HZ. 3 PHASE 1922 240VAC 60 HZ. 3 PHASE

POWER SUPPLY Electrical power to be supplied to the oven by a four conductor service for three phase.

Black conductor is hot. Red conductor is hot. Orange conductor is hot Green conductor is ground.

MAIN FAN CIRCUIT Power is permanently supplied through the 10 amp fuses, through the normally closed

oven cavity hi-limit thermostat, to the normally open main power switch and to terminal number 1 of the 30 minute cool down timer. Closing the main power switch enables the 30 minute cool down timer. The 30 minute cool down timer supplies line voltage to the coil of the main fan relay, its contacts now close, supplying 208/240VAC to the main fan motor. Voltage is also supplied to the primary of the control transformer, the conveyor motor, the oven control and the infrared heater switch. NOTE: Model 1922 ovens use a 240VAC to 208VAC step down transformer for the main fan motor

TEMPERATURE CONTROL Closing the main power switch supplies 208/240VAC to the primary of the control

transformer. Secondary voltage, 24VAC, is supplied to the oven control. The oven control is set to desired temperature. The thermocouple will provide varying millivolts to the oven control. The oven control supplies 208/240VAC to the coil of the heater relay at intermittent intervals to maintain the desired temperature. The display on the oven control will indicate when the main heater relay is energized. NOTE: The display also indicates oven temperature.

INFRARED HEAT Closing the infrared heater switch supplies line voltage to the coil of the infrared heater

relay, its contacts now close, supplying 208/240VAC to the infrared heaters.

CONVEYOR DRIVE Closing the main power switch supplies 208/240VAC to the primary of the control

transformer and, through the air pressure switch, the Infrared heater switch, to the conveyor motor. Secondary voltage, 24VAC, is supplied to the oven control. Setting the oven control to the desired time outputs voltage, through a reversing switch and capacitor, to the conveyor motor. NOTE: The conveyor system uses a hall effect sensor and magnet to prove operation of the conveyor motor. If the conveyor motor is not running, “BELT JAM” is indicated on the display.

AUTOMATIC COOL DOWN When the machine is started, the time delay relay timing circuit is enabled, permitting

the main fan to operate for approximately 30 minutes after the machine is shut off, to cool the machine. The 30-minute time delay relay will keep the coil of the main fan relay energized, maintaining operation of the main fan motor for 30 minutes.

DTF – 1920 Series Service Manual

SCHEMATIC DIAGRAM

MODEL 1921 S/N 8001207 and Below

DTF – 1920 Series Service Manual

SCHEMATIC DIAGRAM

MODEL 1922 S/N 8001207 and Below

DTF – 1920 Series Service Manual

SCHEMATIC DIAGRAM

MODEL 1921 / 1922 S/N 8001208 and Above

DTF – 1920 Series Service Manual

TROUBLESHOOTING GUIDE

1921 208 VAC 60 HZ. 3 PHASE

1922 240 VAC 60 HZ. 3 PHASE

SYMPTOM POSSIBLE CAUSE EVALUATION Oven fan will not run Incoming power supply Check circuit breakers. Reset if required. Call power

co. if needed.

Fuses, 10 Amp, motor and

controls

Fuse holder Check, replace if necessary.

Hi-limit thermostat,

Oven cavity

Switch, main power Check continuity between switch terminals. Replace

30 minute time delay relay Check for supply voltage to 30 minute time delay relay

Relay, main fan Check for supply voltage to relay contacts, if no voltage

Transformer, Motor

(MODEL 1922 ONLY)

Circuit breaker(s), 3A. Push and reset circuit breakers. Check for voltage to

Main fan motor Check for supply voltage at motor. If no voltage is

Capacitor Check for shorts or grounds.

Oven will not heat Main fan motor Check for main fan operation. If it is not operating, refer

Air pressure switch This normally open switch should close when the main

Check, replace if necessary.

Terminals are normally closed. If open, reset thermostat and retest. If thermostat will not hold for maximum oven temperature, and oven is not exceeding temperature setting, check for proper location of capillary bulb in its spring holder. If the capillary checks okay, replace the hi-limit thermostat.

switch as needed.

at terminals #1 and #6. If no voltage is present, trace wiring back to main power switch. If there is supply voltage at terminals #1 and #6, check for output voltage at terminals #2 and #3. If there is incoming voltage but no output voltage, and the main power switch is on, replace the 30 minute time delay relay.

is present, trace wiring back to power supply. Check for supply voltage to the coil of the main fan relay. If no voltage is present, trace wiring back to the 30 minute time delay relay. If voltage is present, check to insure contacts are closing. Replace as needed. Check for 240 VAC supply to the transformer primary. If no voltage is present, trace wiring back to relay. If 240VAC is present at transformer primary, check for 208VAC at the transformer secondary. If there is primary voltage, but no secondary voltage, replace transformer.

the circuit breaker. If no voltage is present, trace wiring back to the main fan relay. If there is voltage present, proceed. Check for continuity through the circuit breaker, if the circuit breaker has been reset and there is no continuity through the circuit breaker, replace the circuit breaker.

present, trace wiring back to circuit breakers. WITH POWER OFF: Check for opens, shorts or grounds. Turn fan blade to check for locked rotor.

WARNING: Capacitor has a stored charge, discharge before testing.

to “Oven fan will not run”.

fan is activated. Refer to the “Removal and installation” section for proper adjustment. Replace as needed.

DTF – 1920 Series Service Manual

Control transformer Check for 208/240VAC supply to the primary of the

control transformer. If no voltage is present, trace wiring back to the main power switch. If voltage is present, check for 24VAC at the transformer secondary. If there is primary voltage, but no secondary voltage, replace the control transformer.

Oven control Check for 24VAC supply to control. If no voltage is

present, trace wiring back to control transformer. If 24VAC is present, check for a read-out on the display. If there is 24VAC supplied, but there is no read-out on the control display, replace the oven control. If there is a read-out on the control, set the control to maximum temperature (see installation operations manual for temperature adjustment). With the control set at maximum temperature, check for supply voltage to the oven control at terminals J3-12 and J3-3. If there is no voltage present, trace wiring back to the air pressure switch. If there is voltage present, check for output voltage at the Main heater relay (R1). If there is voltage at the Main heater relay, proceed to “Main heater relay” for next check. If there is no voltage at the Main heater relay, trace wiring back to the oven control. If there is no voltage output at the oven control, check the read-out on the control. If the control reads “PROBE FAIL”, this indicates that the thermocouple has failed or become disconnected from the oven control.

Thermocouple Check to be sure that the thermocouple is securely

connected to the oven control. If the thermocouple is connected to the oven control, and the control indicates “PROBE FAIL”, disconnect the thermocouple from the oven control and measure the resistance of the thermocouple. The thermocouple should read approx. 11Ω. If these readings are not achieved, replace the thermocouple. If these readings are correct, proceed.

Oven control If the thermocouple checks good, but the oven control

display indicates that there is a thermocouple failure, replace the oven control. If the oven control indicates a temperature reading but the oven will not heat, proceed.

Thermocouple WITH POWER ON AND THERMOCOUPLE

ATTACHED TO THE OVEN CONTROL: Measure the DC millivolt output of the thermocouple. Refer to the thermocouple chart (located in the “Removal” section of the manual) for proper millivolt readings. If these readings are not achieved, replace thermocouple.

Oven control If the thermocouple checks good, but there is no

voltage output to the Main heater relay, replace the oven control. If there is voltage output to the Main heater relay, proceed.

Main heater relay Check for supply voltage to the relay coil. If voltage is

present and the relay will not activate, replace the Main heater relay. Also check each relay contact for high voltage input and output.

Heating element(s) Check the Amp draw on each power leg for proper

DTF – 1920 Series Service Manual

a digital multimeter. The element resistance should be as follows: 208V – 43 ohms approx. 240V – 57 ohms approx. Replace heating elements as needed.

No Infrared Heating Main fan motor Check for main fan operation. If it is not operating, refer

to “Oven fan will not run”.

Air pressure switch Check for 208/240VAC to the air pressure switch. If no

voltage is present, trace wiring back to main power switch. This normally open switch should close when the main fan is activated. Refer to the “Removal and installation” section for proper adjustment. Replace as needed.

Switch, Infrared heater Check for 208/240VAC to the Infrared heater switch. If

no voltage is present, trace wiring back to the air pressure switch. WITH POWER OFF: Check continuity between switch terminals. Replace switch as needed.

Infrared heater relay Check for supply voltage to the relay coil. If no voltage

is present, trace wiring back to Infrared heater switch. If voltage is present and the relay will not activate, replace the Infrared heater relay. Also check each relay contact for high voltage input and output.

Infrared Heating element(s) Check the Amp draw on each power leg for proper

load. Check the specification plate for rating information. If the amp draw is high or low, check the individual elements for opens, shorts and proper resistance. WITH POWER OFF: To check resistance of the elements, remove all leads from the elements and use a digital multimeter. The element resistance should be as follows: 208V – 45 ohms approx. 240V – 58 ohms approx. Replace heating elements as needed.

Oven heats with switch off Main heater relay or

Infrared heater relay

The Main heater relay or Infrared heater relay has probably failed in the closed position. If there is no voltage to the operating coil, but there is high voltage at the relay output, replace the heater relay.

Intermittent heating Thermal/overload of motor The main fan motor is equipped with internal thermal

protection and will cease to operate if overheating occurs. As the motor overheats and then cools, this will cause the oven to cycle on and off intermittently. Improper ventilation or lack of preventive maintenance may cause this. Also, most of the problems listed under “Oven will not heat” can cause intermittent failure.

Conveyor will not run NOTE: Display will indicate

“Belt Jam”

Power supply Check circuit breakers, reset if required. Check power

plug to be sure it is firmly in receptacle. Measure incoming power, call power co. if needed.

Fuse, 10 Amp Check, replace if necessary.

Fuse holder Check, replace if necessary.

Hi-limit thermostat, oven cavity Terminals are normally closed. If open, reset

thermostat and retest. If thermostat will not hold for maximum oven temperature, and oven is not exceeding temperature setting, check for proper location of capillary bulb in its spring holder. If the capillary checks okay, replace the hi-limit thermostat.

DTF – 1920 Series Service Manual

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