Hi! I have a problem w/my Carrier Weathermaker 9000? (it's a 58MXA)
not heating.

Though the "component test" checks out OK, this is the ONLY time that
I see that I see the HSI energized (the ignitor). Also, the test of
the pressure switch in the op's manual (i.e., disconnect the inducer
motor, call for heat, and make sure that the HSI is NOT glowing after
about a minute) was fine.

I see a steady ~26VAC signal to the pressure switch.

Other checks:

- air intake/exhaust not clogged (good flow when inducer runs)
- inducer motor supply voltage fine (120VAC)
- inducer cap fine (3.0 uF and resistance huge @ DC)
- install was years ago so PVC sizing must be right
- no backup of water in the drain system
- no clogging of the other rubber/plastic tubing (from the pressure
switch to the burner box)

So am I at a point where the board is in question or might it still be
the pressure switch?

I've tried shorting across the terminals, but an HVAC tech has
informed me that not doing it at the proper time or with the
connections previously ok (i.e., apparently you can't just disconnect
the leads and short the terminals) won't show the proper behavior.

???
HELP!

Thanks