Aprilaire dehumidifier does not drain properly when connected to a condensate pump

Safety first: Unplug both the dehumidifier and condensate pump before servicing. Water and electricity are a hazardous combination.

• Check pump operation: Manually fill the pump reservoir with water and plug it in. Verify it pumps out water and shuts off properly.
• Inspect discharge line: Ensure the pump’s discharge tubing is not kinked, blocked, or run too high above the pump’s rated lift.
• Verify drain slope: Confirm the dehumidifier’s drain line slopes downward into the pump reservoir with no upward loops.
• Check safety switch wiring: If the pump has an overflow safety switch wired to the dehumidifier, verify it is wired to the correct low-voltage interlock terminals so that an overflow will shut off the dehumidifier.
• Replace pump if failed: If the pump does not run or evacuate water, replace the condensate pump with a compatible model.