Evap fan running nonstop
Hey everyone! Former HVAC Tech but been out of the game a long time…I’m hoping to get some opinions from HVAC techs or anyone familiar with Goodman/Daikin equipment.
I have a system that was professionally installed in August 2025, and it has worked great for almost a year. This behavior just started this week, so I’m trying to determine what suddenly changed.
Equipment:
Outdoor unit: Daikin DC5SEA6010AA (5-ton, single-stage)
Air handler: Goodman AMST60DU1300AA
Thermostat: ecobee
I’m in South Florida, so humidity control is just as important as temperature for us.
Here’s what I’ve observed:
While the AC is actively cooling, everything seems normal.
The house cools properly.
Humidity steadily drops during the cooling cycle.
Outdoor suction line is cold.
I vacuumed the condensate drain and pulled a small amount of water out, so there may have been a partial restriction.
The strange part happens after the cooling cycle satisfies.
When the thermostat reaches set point:
The outdoor condenser shuts off.
The indoor blower continues running and doesn’t shutoff.
The airflow feels just as strong as it did during active cooling (it doesn’t seem to slow down).
During that blower-only period, the indoor humidity begins climbing again relatively quick.
Eventually another cooling cycle starts.
Thermostat settings
Fan = Auto
Minimum Fan Runtime = 0 minutes
I factory reset the ecobee and reconfigured it from scratch because I wondered if settings like AC Overcool, Cooling Dissipation, or Differential had somehow gotten changed.
TLDR: my unit that is less than a year old is cooling and removing the humid very well. However, the blower motor in the air handler runs nonstop and the problem just started this week. While it’s running, it rapidly increases the humidity in the house until eventually, this compressor kicks on and cools the house back down and dehumidifiers it.