(k) The dryer safety thermostat(s) (TH1 and TH2) cut off power to the
dryer heaters if ambient temperature in the dryer exceeds approximately 165o F. A
constant heat condition (shorted triac) in the dryer could cause this, as could a clogged
air flow, or a blower motor failure. You must manually reset the safety thermostat(s).
See figures 1-23 (front dryer) and 1-24 (lift-out dryer). Allow the dryer to cool before
pressing the reset button. If a thermostat trips a second time, remove the dryer
assembly, clean it, and check all components.
(l) Triac testing requires that you disconnect the power. Take a piece
of tape and mark the wires at the triac so that you do not reverse them when you
reconnect. Remove the wires from the terminal strips at the triac. Use an ohmmeter to
check for infinite resistance across terminals MT1 and MT2. Using a jumper, or the
bare ohmmeter probe, connect the gate terminal to terminal MT2. There should not be
a low ohms reading across terminals MT1 and MT2.
Some ohmmeters do not provide enough current to activate the triac.
Therefore, this is not a sure test. This is only a functional check that can
indicate that a triac is probably good.
Figure 1-23. Front dryer and safety thermostat reset button.