Honeywell Hardware & Accessories - Recent Questions, Troubleshooting & Support
Honeywell ST9120C Problem: Blower does not start.
I've got the same problem, there is no voltage at the 'heat' terminal on the control board when calling for heat, or at the 'cool' terminal when in AC mode. If I power up the blower from a separate 120V source it runs fine, so I suspect it's a bad relay on the board.
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