Home AC - Is my condensate pump broken?

June 25, 2010 6:23 PM

So yesterday I heard this noise coming from the basement all day. It turns out the condensate pump on my AC (water goes from AC to some tank in the floor and the pump pumps it outside AFAIK) was continually running all day. I unplugged it and plugged it back in, and it hasn't run since. How can I tell if the pump is working properly or not?

I looked in that tank in the floor and it looks about half full of water.

Is it normal for that tank to have some water, or is it supposed to all get pumped out?

posted by GregX3 to Home & Garden (5 answers total)

There is always a little bit of water left in the bottom of the tank, but it probably shouldn't come up to halfway without the pump coming on (though, theoretically, it could be set up that way).

The pump has a float switch on it that turns the pump on when the water reaches a certain level. If you can see the float switch, you can probably actuate it with your hand and see if the pump starts. If you can't see the float switch, then it isn't working. In that case, you should pull out the pump (hopefully, whoever installed it left a cable or something attached to it to pull it up). Once you get it out of the water, you can test if it is working or not (don't let it run dry for any significant amount of time).

Pumps are cheap and they don't last forever, so it isn't a big deal if you have to replace it.
posted by ssg at 6:50 PM on June 25, 2010 [1 favorite]

Sometimes the float switch that operates the pump gets stuck on scum or something in the water catching bucket. Cleaning the it with bleach might do it - but make darn sure the thing is unplugged when you clean it.
posted by Flood at 9:18 PM on June 25, 2010

Response by poster: Here's an update. The pump did come on last night and then proceeded to run for six hours straight. It felt pretty warm so I unplugged it and plugged it back in. It stayed off after that.

There were only a couple of inches of water left in the tank.

So either the floater switch is getting stuck or it's suppossed to run for a very long time.

I can't remove the lid of the tank because it has pipes going into it and I don't know how to detach those. It does have a little cap where I can peek in though?
posted by GregX3 at 9:45 AM on June 26, 2010

So either the floater switch is getting stuck or it's suppossed to run for a very long time.

Sounds like it. It isn't supposed to run for 6 hours. You aren't going to be able to do anything to fix this without opening up the tank. Hopefully, it was installed with fittings that can be unscrewed (look for the ribbed ring around the pipe).
posted by ssg at 10:39 AM on June 26, 2010

I had a similar problem with my sump pump a few years ago, and found that my pump had airlocked, causing it to run without actually moving any water. This happened because a relief hole was not drilled in the appropriate pipe when the pump was installed (by, ahem, yours truly). Apparently this is a common mistake. I pulled the pump out of the sump crock and drilled the appropriate hole, and have had no problems since.
posted by jon1270 at 7:28 PM on June 26, 2010