American Dryer Corp. ML-410 - Manual (Page 13)

9
DRY
This selection prepares the machine for a “Material Drying Command” from the Phase 7 Microprocessor Controller
(computer).
NOTE: Before a drying cycle can be selected, the tumbler (basket) section must be in the level
position and both the Front Horizontal Doors as well as the Lint Drawer must be closed.
The PLC (Programmable Logic Controller) senses that the machine is level by the two (2) level switches located
on the left side of the base section. One (1) switch is towards the rear of the machine and the other switch is
towards the front of the machine.
The PLC senses that the load doors are closed by the two (2) proximity switches located at the top center, of the
dryer above the doors. These switches are magnetically actuated by magnets located on the doors.
The PLC senses the Lint Drawer by a push type switch located on the right side of the lint drawer door.
IMPORTANT: THE LINT DRAWER MUST BE CLOSED BEFORE BRINGING THE
MACHINE TO A LEVEL POSITION.
If the tumbler (basket) section does not return to a level position;
1. Verify that a “Door Closed” signal is being sensed by the PLC.
2. Check that 80 PSI (5.512 bars) of compressed air is supplied to the machine and that the “Front Down” or
“Rear Down” solenoid is being actuated by the PLC.
3. Verify that the Lint Drawer is in the closed position. This signal can be easily verified since it is a PLC
input.
Refer to the PLC signal information included in the ladder diagrams and schematics supplied with the machine.
ONE or BOTH BURNERS DO NOT IGNITE
The model MLG-410 dryer has two (2) burner boxes. Each burner box has its own Gas Valve, Spark Ignitor/
Flame-Probe Assembly, and DSI (Direct Spark Ignition) Module.
DSI (Direct Spark Ignition) MODULE
When the dryer calls for heat, and ALL dryer safety switches are satisfied, a 24 VAC control signal is supplied
to both DSI Modules. The DSI Module L.E.D. (light emitting diode) indicators will light “red” for approximately
1.5 seconds of pre-purge, the L.E.D. (light emitting diode) indicators will light “green.” Each DSI Module will
energize its’ respective gas valve and provide an 8 second spark to its’ Spark Ignitor/Flame-Probe Assembly.
The gas in both burner boxes should ignite. If ignition does not occur in one or both burners after 8 seconds, the
flame will not be sensed by the Spark Ignitor/Flame-Probe Assembly and the DSI Module will go into the
“LOCKOUT” mode lighting the L.E.D. (light emitting diode) indicator(s) “red” continuously. THERE ARE
NO IGNITION RETRIES BY THE DSI MODULE. Stop the dryer at this point and restart another drying
cycle. It may take several restarts to clear the gas supply piping of air.
NOTE: “BURNER FAULT” will occur during the initial set up of the machine, indicating that
the burners are not lighting due to air in the gas line.