[Discseven]

Originally Posted by wwest

Puzzle..


When in low speed both resistors are in the circuit, in series. Should one of them overheat and thereby cause it's associated thermostatic switch to close the blower speed will increase.

But....

With the thermostatic switch closed the resistor will/would cool to the point that the closed switch should open and the speed should retard. A cycle back and forth should ensue.

The only possible explanation I can come up with is that once the thermostatic switch closes it sticks closed.

File/burnish the contacts so the contact surface is smooth..?


Or did adjusting the gap solve the problem?

These coils heat up nearly instantly. I suspect that given the nearly closed contact, the immediate heat was causing the shunt to close and so the jump from low to medium a few seconds after starting AC.

Drove for an hour today and no jump from low to medium. Had 1 surprising jump from medium to high... that's NEW. I failed to look at shunts with AC on and resistor out so did not check to see how far they move when coils get hot. Might be they need a greater gap than 3/64." Will sand contacts when resistor is pulled---good idea Will. TY again for shunt note.

Have not gotten to "noise" yet as planned. Will see about attending in the afternoon.