Merco PD-4, Parts & Service Manual

SEQUENCE OF OPERATIONS

Power is permanently supplied to the timer and the “push to toast” button. When depressing the
“push to toast” button, power is supplied through the timer(control board) to a normally open
relay, applying power to the heater cards along wiht the heat indicator light.

The heater cards operate at a constaant voltage and wattage. The hold time of the toaster
determines the lightness or darkness of the product and is adjusted by the light/dark control dial
on the front of the toaster.

When the heating sequence is complete, the timers open the normally closed upper and lower
solenoids, activating the linkages, opening the doors and allowing the product  to drop down
into the receiving tray.

NOTE:

At any time during the toasting cycle, the circuit may be interrupted by pressing the reset but-
ton. This will stop the voltage and open the release doors.

TABLE OF CONTENTS

SEQUENCE OF OPERATIONS............................................................................................         2
WIRING DIAGRAM - 120V....................................................................................................         3
WIRING DIAGRAM - 208V & 240V.......................................................................................         4
TROUBLESHOOTING GUIDE..............................................................................................         5
REMOVAL / INSTALLATION / ADJUSTMENT

HEATER CARD........................................................................................................         6
DOOR LINKAGE......................................................................................................         7
LOWER DOOR.........................................................................................................         7
TOAST SUPPORT....................................................................................................        7
UPPER & LOWER CHASSIS...................................................................................         8

COMPONENT TEST PROCEDURES

RELAY......................................................................................................................         8
ELEMENTS...............................................................................................................        8
TOAST LIGHT..........................................................................................................         8
TOAST BUTTON & RESET BUTTON.....................................................................         8

TIMER PERFORMANCE CHART.........................................................................................         9
INSTALLATION..................................................................................................................           10
SPECIFICATIONS..............................................................................................................         11-12