When to Replace Your Condensate Pump

Condensate pumps last 5 to 10 years. These small pumps collect and move condensate water (the moisture your AC or high-efficiency furnace produces) from the unit to a nearby drain or outside. If your furnace or air handler is in the basement, attic, or anywhere that's not directly above a floor drain, there's likely a condensate pump doing the work. The pump sits in a small reservoir that collects the drip-drip-drip of condensate water. When the water level rises, a float switch triggers the pump, which pushes the water through a small vinyl tube to a drain, utility sink, or exterior discharge point. Most residential condensate pumps move about 65 to 80 gallons per hour... far more than the 5-20 gallons per day a typical AC system produces, so the pump only runs in short bursts. The biggest enemy of condensate pumps is algae and slime. The warm, wet environment inside the reservoir is perfect for biological growth. Over time, a greenish-brown slime builds up and clogs the pump inlet, the discharge line, or the float switch. When the float switch gets stuck in the down position, the pump never kicks on... and the reservoir overflows. In a finished basement, this means water damage. In an attic, it means water dripping through the ceiling. Many modern condensate pumps have an overflow safety switch that shuts down the HVAC system if the reservoir gets too full. This prevents water damage but means your AC or furnace stops working... usually on the hottest or coldest day of the year.

Replacing a condensate pump takes 15 to 25 minutes. The pump plugs into a standard outlet (some have the HVAC system plugged into a piggyback plug on the pump for the safety shutoff feature).

Steps: unplug the old pump from the outlet, disconnect the condensate drain line feeding into the reservoir (usually a friction-fit PVC connection), disconnect the discharge tubing from the pump outlet, remove the old pump, set the new pump in place, connect the condensate drain line to the new reservoir inlet, connect the discharge tubing to the new pump outlet, plug in the pump (use the piggyback plug setup if your system uses one), and test by pouring water into the reservoir.

If the old pump used a safety switch (the HVAC system was plugged into the pump), make sure to wire the new pump the same way. The safety switch is the feature that shuts off the HVAC system if the pump fails... without it, a dead pump means water damage.

Routing the discharge line: the line should run slightly uphill from the pump to the drain point. Avoid sags or dips where water can pool. Keep the run as short as possible. Most pumps can push water 15-20 feet vertically, which is more than enough for residential applications.