Quick answer
A condensate pump collects water from an air handler that cannot drain by gravity and pumps it to a drain or outside. In Miami's humidity these pumps run constantly and fail from algae, clogged check valves, worn motors and tripped safety switches. Symptoms are water around the pump, the AC shutting off, or a pump that runs nonstop.
Written by Sylvia Denton, HVAC Guides Editor. Updated 2026-09-22.
Condensate pumps are common in Miami wherever the air handler sits below its drain: basements are rare here, but closets on interior walls, condo units far from a drain riser, converted garages and some attic and ceiling installs all use them. A small reservoir collects the water and a float turns on a pump that pushes it through a thin tube to a drain.
In our climate that pump can cycle every few minutes all summer. Algae and slime build up in the reservoir and check valve, the float sticks, and the motor wears out. Most pumps also have a safety switch wired to shut the AC off when the reservoir gets too full.
We clean or replace the pump, clear the discharge line, and confirm the safety switch works so the next failure shuts the system off instead of flooding the floor.
