ADC AD-200 Service Manual download pdf (Page 74)

Next reverse leads to temperature sensor black to black and red to white. At that point, you will

measure approximately 1.8 amps, this is the turn on voltage of the device. If you hold the temperature

sensor in your hands and warm it, the reading will decrease corresponding to a higher current flow

(the decrease is very slight tenths of a volt).

2) The Rotational Sensor is a magnetic proximity switch that is mounted on the basket (tumbler) wrapper

on the left side of the dryer. There is a magnet mounted to the side of the basket (tumbler). After

each rotation of the basket (tumbler), the magnet passes by the proximity switch causing the contacts

to close and pulse the Phase 7 microprocessor controller (computer). Whenever the magnet is over

the proximity switch there should be contact closure.

When a drying cycle is started, the blower (squirrel cage fan) output switches on putting 24 VAC on

the blower (squirrel cage fan) contactor coil, which in turn pulls in the contactor starting the blower

(squirrel cage fan) motor turning. Through the contactor relay, this also triggers an input signal to the

Programmable Logic Controller (PLC) disabling the non-tilting function. Moments later, the basket

(tumbler and drum) begins to rotate because the output turns on thereby pulling in the basket (tumbler

and drum) forward contactor. Next, the Heat “On/Off” output will turn on if there is a call for heat,

supplying 24 VAC to the heat circuit through the safety circuits.

a) The first safety circuit is the Manual Reset Exhaust Hi-Limit, which is located on the bracket

above the lint basket with the temperature sensor. On a temperature rise of 225º F (107º C) or

higher, the thermal switch opens breaking the heat circuit.

b) A second safety circuit is the Burner Manual Reset Hi-Limit Switch located on the side of the

burner. On a temperature rise of 330º F (166º C) or higher, the thermal switch opens breaking

the heat circuit, this switch must be manually reset.

c) A third safety circuit is the Sail Switch, which is attached to the front of the burner box. This

device pulls in when the blower (squirrel cage fan) is operating correctly and verifies proper

airflow.

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 off, DSI module will go into a “LOCKOUT” 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 micro amp signal is created between the flame-probe and ground, which in turn will keep

the burner on. The Heat “On/Off” output cycles the heat unless there is a fault at a safety

sensor. At the end of a cycle the air jet output turns on to clean off the blower (squirrel cage

fan). The audio alert output energizes the 24 VAC Audio Alert horn mounted on the right door,

the end of cycle output energizes the 24 VAC End of Cycle light found on the top of the front

panel.

c. PLC

1) The PLC can consist of one (1) or two (2) modules; a main module and in some cases an expansion

module is used for additional inputs and outputs.

NOTE: The information listed on page 74 is generic in nature; refer to blueprints for specific details.

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ADC AD-200 Service Manual Page 74