How to Replace a Condensate Pump

Man repairing an AC unit
  • 1-2 hours
  • Intermediate
  • 20-100
What You'll Need
Sockets or wrenches
Utility knife
Replacement condensate pump
Hose clamp
Rubber hose

Your air conditioning has stopped cooling and an online site suggests it may be the condensate pump. Those two words sound like a foreign language. What can you do? The condensate pump is not as complicated as the name implies. It is a sort of safety valve that shuts off the unit before water can cause damage.

As the name implies, it rids the air conditioning unit of condensation. In humid climates or on sweltering days, the coils of a cooling unit can gather quite a bit of moisture. The condensate pump forces that water through a pipe to drain outside. If the pump falters, a float engages a shutoff valve. When that happens, the unit shuts down. If that’s the case, you can change the pump yourself.

Step 1 - Analyze the Situation

A malfunctioning air conditioner may not need a total overhaul. Several minor issues could be the cause. First, check the circuit breaker or fuse in the main electrical panel. If it seems normal, move on to the switch panel located next to the unit to ensure it is switched on.

Before checking other possible causes, switch off the unit and flip the main electrical breaker that feeds it. Remove the cover from the unit to access the condensate pump. It will be near the coils within the air conditioning casing or adjacent to the unit. Loosen the cover over the pump to expose it. Turn on the power to the unit and adjust the thermostat so the unit should start. If the pump doesn’t activate, shut off the power again.

Step 2 - Remove the Pump

man repairing an AC unit

The condensate pump will be attached to the air conditioner case with two to four sheet metal screws. Remove the condensation drain hose from the unit, unplug the electrical connections making sure of their positions, and loosen the retaining screws. Take loose the discharge tube and remove the pump from the PVC drain pipe. If the old tubing and clamp were damaged in removing them, replace them with a new hose.

Step 3 - Install the Replacement

Inspect the old pump to determine what might have caused the failure. The float likely was sticking in the engaged position because of algae and other deposits. Clean the drain tube well with bleach and water. Fit the new pump into the unit and use the same retaining screws to attach it. Make sure it settles over the PVC drain and reattach the discharge tube.

Reconnect the electrical wires on the proper terminals. The low voltage wire to the float switch should be reattached with wire nuts. Replace the cover over the pump and the casing around the condenser. Flip the circuit breaker and external switch. Adjust the thermostat to power up the unit. Cool air begins to flow. You’ve spent hardly more than $50 to make the repair. Replacing the condensate pump has solved the problem.