American Dryer Corp. AD-200 Clothes Dryer User Manual


 
71
5. Heat Circuit (Gas Models):
IMPORTANT: The L.E.D. indicator on the computer board that reads "DOOR" must be on in
order to successfully troubleshoot the following.
Theory of the "HEAT" Circuit (Gas):
When the computer senses a drop in temperature below the preset temperature it will send 24 A/C volts
out of pin #4 of the 15 pin computer harness. There are 3 heat safety devices in the dryer that will stop the
voltage from reaching the D.S.I. direct spark module. The first one the voltage must pass is the 225º thermostat.
The second one is the 330º burner hi-limit thermostat, and the third safety device is the sail switch. When all three
of these safety devices have been satisfied the voltage then arrives at the "TH" terminal of the D.S.I. module.
The D.S.I. technical manual P/N-450142 will give you more information on what happens at this point once the
voltage reaches the "TH" terminal on the D.S.I. module.
Path of Voltage for the "HEAT" Circuit:
The 24 A/C voltage leaves the computer on pin #4 it then travels to terminal block #2 position #3. Now
this voltage travels through connector J2, pin #3, and connector J6 pin #4. After this J6 connector the voltage
now is present at the 225º thermostat, the voltage then passes through the thermostat and travels through the
same two connectors... different pin #'s of course, J6 PIN #3 and J2 pin #4. This voltage now is present back on
terminal block #2 but now it's position #4. The voltage now passes through J8 pin #1 from here the voltage must
go through the other two safety devices the burner thermostat (hi-limit) and the sail switch (air flow switch).
Before it reaches the "TH" (thermostat) connection on the D.S.I. module. The other side (GND) of the A/C 24
volts from the D.S.I. module travels through J8 pin #2 and then to TB2 #7 (GND).