The details below provide a quick and easy trouble shooting guide to identify why a condensate pump is not working. It covers all types of condensate pump installations from residential AC equipment to commercial installations.
General Condensate Pumps Maintenance
Routine maintenance is critical to keeping your condensate pump functioning reliably. Maintenance should be carried out 1–2 times a year, or more frequently if the system operates in high-humidity environments, dusty mechanical rooms, or areas prone to biological growth.
The best times to perform maintenance are at the start and end of each cooling season, when the pump is most active. Begin by turning off power to the pump for safety. Remove any debris from the reservoir. Clean the float switch to ensure it moves smoothly.
Check the valve for wear or buildup. If the pump was recently installed, make sure it is the right size for the HVAC system. It should match the system’s condensate production rate and the needed lift height.
Make sure the discharge hose has no tight bends, pinches, or blockages. These issues can lower the flow rate, create pressure buildup, or cause overflow.
Condensate Pump Not Working
If your pump isn’t switching on, the issue could be electrical, mechanical, or installation-related. Start by checking the power supply—if your pump has a molded plug, confirm that it’s securely plugged in and the circuit breaker in the electrical panel hasn't tripped. For hardwired pumps, it’s essential to have a qualified technician inspect the wiring and connections.
Next, examine the float switch inside the reservoir; if debris, algae, or scale is present, it may prevent the float from rising and triggering the pump. Gently clean the float area and make sure it moves freely. Also, look for signs of water damage or overheating, which could indicate internal motor failure or prolonged dry operation. If the pump remains inactive after these checks, it may require professional service or replacement.
Pump Is Running Continually & Not Switching Off
A pump that runs continuously without stopping is usually a sign that water isn't discharging properly.
First, inspect the discharge hose for kinks, blockages, or improper routing that could be causing a backup. Even partial obstructions can restrict flow enough to prevent the reservoir from emptying, which keeps the pump running. If this is a new installation, double-check the head height against the pump’s rated performance—if the vertical lift is too high, the pump may not be able to overcome it.
Also, inspect the float switch mechanism; if it’s stuck in the "on" position due to sludge or misalignment, the pump will continue running even if the water level is low. Prolonged operation in this state can lead to motor burnout, so shut off the unit and address the issue promptly. Cleaning or adjusting the float switch may resolve the problem.
The Pump Seems To Continually Cycle
If your pump starts and stops frequently, even when the water level hasn't changed significantly, it may be a sign of check valve failure or air trapped in the discharge line. First, perform a thorough cleaning of the pump, especially the float switch and reservoir area. Sludge or algae can cause false float triggers. If the issue persists, focus on the check valve.
A failing or leaking check valve can allow water to flow back into the tank after each cycle, causing the float to rise repeatedly and the pump to short cycle. This repeated start-stop pattern can shorten the pump's lifespan and reduce energy efficiency. Replacing the check valve with a new, compatible one should correct the issue. It’s also worth checking that the drain line is properly sloped and vented to avoid airlocks, which can mimic check valve problems by trapping water in the line.
What Happens If You Skip Maintenance on Your Condensate Pump?
Neglecting regular maintenance of your condensate pump can cause serious problems. One common issue is extreme algae buildup in the reservoir. If left untreated, algae can clog the drain line, jam the float switch, and block the check valve.
This can result in water leaks, HVAC system shutdowns, or even costly water damage to ceilings, floors, or equipment. Algae thrives in the moist, warm environment inside the reservoir, especially during peak cooling seasons when the pump is working harder.
Tip to prevent algae growth and maintain consistent pump performance :
Prevent algae from the start: Algaecide tablets work best when used right after installation to stop buildup before it starts. If they’re forgotten or not replaced, algae can accumulate — and once that happens, tablets alone can take a long time to break it down.
For faster cleaning: Pump hot (not boiling) soapy water through the system using regular dish soap.
Why it works: Most buildup in AC equipment is made up of human skin cells, which are fat-based. Dish soap contains chemicals that break down fats, and the hot water helps loosen debris. This method quickly cleans the pump, sensor, and discharge line — often faster than any algaecide tablet.
By staying on top of maintenance, you’ll extend the life of your condensate pump, protect your HVAC investment, and avoid unexpected breakdowns when cooling is critical.