85
2) The Rotational Sensor is a magnetic proximity switch that is mounted on the side of the right hand
11-inch drive wheels. There is a magnet mounted to the side of the wheel hub. After each rotation of
the wheel, the magnet passes by the proximity switch causing the contacts to close and pulse the
Phase 5 microprocessor controller (computer). Whenever the magnet is over the proximity switch
there should be contact closure.
3) There is an auxiliary keypad (touchpad) input to the Phase 5 microprocessor controller (computer).
A short between Pin #1 to Pin #5 of the 6-pin connector is like a "CLEAR/STOP" function on the
keypad (touchpad). The PLC (Programmable Logic Controller) will trigger a clear stop whenever
the dryer is in an unsafe operating mode, then disable the dryer's Phase 5 microprocessor (computer)
from running a drying cycle.
a) Other functions of the 6-pin connector are as follows:
(1) A connection of Pin #1 to Pin #2 will run "A" Cycle.
(2) A connection of Pin #1 to Pin #3 will run "B" Cycle.
(3) A connection of Pin #1 to Pin #6 will run "C" Cycle.
b) When a drying cycle is started, the blower (fan and impellor) output (Pin #5) switches on putting
24 VAC on the blower (fan and impellor) contactor coil, which in turn pulls in the contactor starting
the blower motor turning. Through the contactor relay this also triggers an input signal to the PLC
(Programmable Logic Controller) disabling the tilting function. Moments later, the tumbler (basket
and drum) begins to rotate because the output on Pin #3 turns on thereby pulling in the tumbler
(basket and drum) forward contactor. Next, the Heat "On/Off" (Pin #4) will turn on if there is a
call for heat, suppling 24 VAC to the heat circuit through the safety circuits.
(1) The first safety circuit is the Exhaust Hi-Limit which is located on the bracket above the lint
basket with the temperature sensor. On a temperature rise of 225º F or higher, the thermal
switch opens breaking the heat circuit.
(2) A second safety circuit is the Burner Hi-Limit Switch located on the side of the burner. On a
temperature rise of 330º F or higher, the thermal switch opens breaking the heat circuit, this
switch must be manually reset on models manufactured as of May 26, 1998.
(3) A third safety circuit is the Sail Switch which is attached to the front of the burner box. This
device pulls in when the impellor (fan and blower) is operating correctly and verifies proper air
flow.
If ALL the safeties are properly maintained, 24 VAC will enable the Direct Spark Ignition (DSI)
Module and a try for ignition begins. The DSI module induces a spark (at the spark electrode) and
then opens (energizes) the gas valve for 8-seconds attempting to light the burner. If after
8-seconds the burner does not light the DSI module will go into a "LOCK-OUT" Mode (the gas
valve will be de-energized and the spark will be removed from the ignitor) and will not try to light
the burner again until power is again cycled to the DSI module. If the spark produces a flame then
a microamp signal is monitored between the flame probe and ground which in turn will keep the
burner on. The Heat "On" or "Off" (Pin #4 of the Phase 5 microprocessor controller [computer])
cycles the heat unless there is a fault at a safety sensor. At the end of a cycle the air jet turns on
to clean off the impellor (fan and blower), which turns on Contact Relay #4, thereby signaling an
input to the PLC (Programmable Logic Controller) that the cycle is complete which then turns on
a PLC output relay to turn on the "END OF CYCLE" (E.O.C.) light.