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Honeywell RedLink thermostats have different Deadbands. Why?

Why do the two Honeywell RedLink thermostats have different Auto Changeover Deadband factory settings? The THX9421R5021WW comes preset to 5°F and the TH821R1001 comes preset to 9°F. I am installing both on two air-to air heat pumps in south Florida. Heat pumps are Trane single stage heat with electric backup and single stage cool. Should I leave the Auto Changeover Deadbands at factory settings or make both the same?


  • ratioratio Member Posts: 2,566
    Are you talking about the enforced deadband between the cooling setpoint & heating setpoint. That is 3* in the 8000 series as shipped from the factory, I'm not sure about the 9000 series, but I'd guess 2 or 3*.
  • ChrisJChrisJ Member Posts: 11,274
    I'd make them both the same.
    Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment
  • SWEISWEI Member Posts: 7,356
    Assuming those figures really are correct, I'd suspect this could well be due to fubmlefingering somewhere by the manufacturer. 5°C = 9°F.
  • ratioratio Member Posts: 2,566
    FWIW, I just found out that if an 8321U is programmed for dehumidification by cooling droop, the deadband range changes from 3-9 to 5-9 *F.
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