How To Test Your Central AC Condensate Pump

If you have a central air conditioning system that seems to allow water to run all over your floor, then you likely have a problem with your air handler or evaporator unit. Fortunately, the issue is typically not a major one and likely involves part of the condensate drain system. This system handles the condensation that builds within the air conditioning unit and drops down from the evaporator coil. A collection pan holds the water and a small tube feeds it outdoors. In many cases, the water is pulled out from the pan with the assistance of a condensate pump. Sometimes, this pump may not be working correctly. Keep reading to learn how to test this pump to see if it's the problem.

Locate The Pump

Before you start your investigation, you will need to make sure that your AC unit has a condensate pump connected to it. These pumps are used if gravity is unable to pull water down through the drainage tube and into a basement or outdoor drain. Most condensate pumps sit separate from the main evaporator unit and can be found just behind the air handler. The pump will be a black or white rectangular box.

Look behind your air conditioner for the box. The pump will also be plugged into an outlet, and it will have two separate plumbing lines attached to it. One line will be attached to the top or side of the device, and this will likely be a larger white PVC pipe. The other drainage line is typically a clear and thin line attached to the other side of the unit. Complete a quick inspection once you find the pump. Make sure that both drainage lines are attached strongly to the pump. Also, make sure the device is plugged in properly.

Investigate Clogs

If the pump appears as though it is connected and plugged in properly, then it is possible that one of the two drainage lines may be clogged by mold or mildew. Mold can form in both the inlet and outlet pipes connected to the device, and the clogs can often be removed. Unplug the device and gently pull the drainage lines out and away from the pump. Retrieve your wet/dry vacuum and place the end of the larger white PVC pipe in the top of the vacuum hose. Gently stuff a towel around the pipe to create a seal around the hose. Hold the towel and the pipe with your hand and turn on the vacuum. If there is a clog in the pipe, then the suction power of the vacuum should release it. 

Complete the same clog removal process with the smaller drain line. Look inside the reservoir of the vacuum to see if any brown or green residue has been removed. If it has not, then place a small amount of vinegar in the condensate drain pan and use a small funnel to force some vinegar down into the smaller drain line. Reconnect the drainage pipes, plug in the pump, and allow it to sit. If you hear the pump working a little while later, then the vinegar has successfully eaten through the clog.

Test The Pump

If clog removal does not work to get the condensate pump working again, then it is possible that the pump itself is not working correctly. A replacement may be needed. You can test the pump by pouring water directly into it. Keep the pump plugged in, but remove the two drainage lines from the device. Set a brick in a bucket and then place the pump on top. Pour some water in the opening where the large white inlet pipe sat. Wait for the pump to activate. If the water is forced out of the side of the pump, then the unit is working correctly. 

If the pump is working, then replace the two drainage lines that are connected to the pump. A large clog has likely formed in one of the pipes and is preventing the pump from working correctly. If the pump did not work during your test, then it is likely that the pump needs to be replaced. Contact and HVAC contractor from a company like Apollo Heating & Air Conditioning for help solving either of these issues.