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How to select/force fan speed on a Bryant 355CAV042060FASA


Premium Member
Sep 15, 2007
Model Number
-major brand-
6-10 years
Issue: This HVAC system used to be managed by a Carrier Infinity SYSTXBBUID01-B thermostat. About a year ago, the display died, and the HVAC technician replaced the thermostat with a FocusPRO TH6220D1028, which doesn't support fan speed control. The home owner (older family member) always ran the system at low speed with the old thermostat, but the current setup is running the blower at high speed, which is too loud for the small home.

  1. Since this person is on a fixed income, I'm trying to figure out if there's a more affordable thermostat which can control the fan speed, or if I can rewire what I have?
  2. Can I force the fan speed with the DIP switches on the control board?
  3. I also wonder if the technician wired it incorrectly, since the "Fan On Plus" feature seems to trigger every time the system calls for cool (so it changes fan speed every time).
  4. Last but not least, if I do replace it with another Carrier Infinity, which wires/terminals do I use? It looks like the blue wire was disconnected at some point.

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