On Jan 29, 8:19*am, DerbyDad03 wrote:
On Jan 29, 8:56*am, cate wrote:

On Jan 28, 8:20*pm, (Lp1331 1p1331) wrote:

That is the fan/limit switch. Jumper the red and blue wires and if the
blower comes on,the switch is your problem. The switches do not give a
whole lot of trouble, but they do fail, and replacement is easy. As I
said in the earlier thread, be sure and cut the little brass jumper at
the bottom of the switch, or you can/will *fry most or all of the 24
volt components in the system. BTDT. *Larry

As I look at this fan switch, I see that the wires attach at 4
positions. *nw, ne, se and southwest *(north being straight up). *What
points of the rose do I short to turn the fan on. *I got a little
confused about the wire color references.
Thanks, you've all been a lot of help. *Long live home repair.

Have you tried to adjust the On limit to make the blower turn on at a
much lower setting - like whatever temp the plenum is at right now?

If your limit switch is anything like the ones I've dealt with, it's a
mechanical device that simply closes contacts when the metal in the
plenum probe expands and contracts, turning the dial so the the
adjustment tabs physically close the contacts. There's no real
"electronics" involved.

If you adjust the On setting so that it physically closes the contacts
you'll have the short you are looking for and you'll know that the
limit switch is the culprit.

It says push (or pull) for on. The "wheel" can be pushed in. I did
so-- no fan.
I'll move the on setting to a very low value and check it out.
Thanks