How to Replace Residential Condensate Pumps

Turn off the power to the existing pump at the breaker. The breaker that runs your condensate pump is typically also connected to the heating, ventilation and air conditioning or air handler system and should be labeled as either air conditioner or air handler.

Disconnect the pump’s power supply. Typically, condensate pumps are plugged into a standard 120-volt outlet. Some systems may also be hardwired into the transformer or safety switch of your HVAC system or furnace. Loosen the wire nuts connecting these wires and separate them. Make note of which wire is connected from the pump to the transformer or the safety switch so that you can connect the new pump wires the same way.

Loosen the hose clamps on the drain tubing with a screwdriver and then remove the intake and outtake drain lines from the pump.

Remove the old furnace condensate pump and then set the new condensate pump in its place.

Insert the furnace or HVAC system's drainpipe into the new pump’s intake port, which is typically found on top if the pump’s tank.

Push the discharge tube onto the barbed discharge port of the new pump. Make sure the end of the tube fits over all of the barbs on the port to ensure it is a tight connection that won’t leak.

Slip the hose clamp down the discharge tubing so that it is about 1/8 inch from the end of the tubing. Tighten the clamp using a screwdriver.

Plug the new pump into the outlet. If it is hardwired into your system, strip about 1/2 inch of insulation from the new pump’s wires using wire cutters.

Connect the wires from the new pump to the transformer or safety switch of your furnace. One of the pump’s wires will typically connect to the furnace transformer’s wire strands, and the second wire connects with the safety switch.

Twist the wires together and cover the connections with wire nuts to secure them. Connecting your condensate pump to your heating or cooling system’s auxiliary safety switch like this shuts down the pump if the discharge line is clogged or if there is a malfunction in the pump or a power outage to prevent overflow.

Turn the breaker on again and test the pump’s functionality by pouring about 1/2 liter of water into the tank through the secondary inlet opening. The pump should turn on after about one minute. If it does not, check your connections.