ac condensation pump problems

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Old 08-24-13, 12:05 PM
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ac condensation pump problems

Hello,

I just purchased a house a year ago. The furnace/ac units are both under 2 years old. We have been running the ac for most of the summer with no problems. I was in the basement the other day and noticed a puddle of water coming out from underneath the furnace. I checked the condensation pump and it is full of water - clearly not doing its job pumping out the water to the drain. However I cannot see where the overflowing of water is coming from. The drain tubes that run to the pump are dry and I can only see water collecting underneath the furnace - have no idea where it is running out from. Anybody have any ideas on what the problem is?
 
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Old 08-24-13, 12:21 PM
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Your piped drains may be plugged and the condensate pan internally is overflowing.
 
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Old 08-24-13, 12:21 PM
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water in line

I just checked the clear plastic drain tube that goes from the pump on the floor up to the ceiling and then down to a drain in the corner of the basement and there is water sitting in the tube until the part where it drops down from the ceiling to the drain - any idea on why the water is not going all the way down the tube? I could understand if the pump was shot why it would be sitting there, but I am still baffled as to where the water is running out underneath the furnace...
 
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Old 08-24-13, 12:42 PM
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Steve, what Furd was referring to was the piping going from the drain pan underneath the evaporator coil to the condensate pump. The clear plastic drain tubing is the output from the condensate pump to the drain. If the pipe from the evaporator drain pan to the condensate pump is blocked, the water will overflow the drain pan and likely collect underneath the furnace.

To clean the drain pipe (usually small diameter PVC pipe), either use a shop vac to vacuum out the clog, or use a small diameter snake (if there aren't too many bends).
 
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Old 08-24-13, 01:55 PM
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Okay I looked a little closer at the pump. There are two tubes going in to the condensation pump. One is the clear plastic tubing going from the pump to the drain. The other is the white PVC pipe going from the furnace to the pump. Which tubing do I need try to shop vac out? Because if its the white PVC pipe I will have to take it out of either the furnace or the pump to get to an opening to clean it out...?
 
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Old 08-24-13, 02:17 PM
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Also I don't have the PVC pipe on the outside of the house. There is a drain in the basement that the clear plastic tubing goes to...
 
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Old 08-24-13, 02:32 PM
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There is a clear plastic tube going into the condensation pump and pvc pipe from the pump to the furnace. Which one do I need to vacuum out? I would have to disconnect the PVC pipe from the pump to clean out if that's the one I need to. Please help
 
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Old 08-24-13, 03:48 PM
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The white PVC is the one you need to clear
 
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Old 08-24-13, 04:12 PM
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The pump has a power, alarm, and run light. The power is the only one that's always been lit up. I was messing around with it and the run turned in and it drained some of the water out and turned off. The pump was full of water before and now I stuck my finger in it and I can just feel a little at the bottom. And also the clear drain pipe still has some water in it. Is that normal? Is the run light on the pump always supposed to be on? I am just trying to figure out if I fixed it or not. Also, with the white pvc pipe, mine goes straight from the furnace into the pump. Where am I supposed to disconnect this pipe to clean it? and how
 
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Old 08-24-13, 04:44 PM
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First, it's normal to have some water visible in the clear plastic drain tubing. Since the pump turned on and pumped water out of the pump reservoir, it appears that the pump is working normally. The pumps I've seen haven't had any lights on them, so I can't say which lights should be on. However, I think that the power light should be always on (when plugged in), and the Run light should come on when the pump is actually running (pumping water out of the reservoir).

To remove the white PVC (inlet) pipe from the pump, you can sometimes bend the pipe slightly while tilting the pump to get the pipe to clear the opening in the top of the pump. If not, you can usually unscrew the top of the pump fairly easily (normally just a couple of screws holding it on). Once the top of the pump is removed from the base, you can slide the pump out and drop the top down to remove it from the pump.
 
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Old 08-24-13, 04:46 PM
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The run light should only be on when the pump is draining. The clear drain pipe should normally have a little water in it. Anytime the a/c is running it is removing humidity (water) from the air and should continue to drain. It is difficult to tell you how to disconnect the white pvc since you haven't posted any photos. Some are installed with a union so they can be easily taken apart for maintenance. Some are threaded. Some are just stuck together without gluing. Some have a "tee" that you add bleach to keep the drain clear. Is there a hose clamp on the clear hose that connects to the pump or the white pvc? If you can get that clear hose disconnected at any point then you can use your shop vac (remove filter) to suck the water out to get the "gunK" out. If you can't figure it out post some photos and I am sure some of the regulars here can help you.
 
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Old 08-24-13, 06:42 PM
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Yes, the pump is likely full of slime thus preventing the float from operating properly to turn on the pump. HOT water will help to cut the slime. Dump the hot water into the pump & allow the pump to kick on. Sloshing the pump around helps as does the addition of some bleach. Repeat several times. Adding 1/4 to 1/2 cup of bleach once a month really helps in reducing the amount of slime which builds up.
 
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Old 08-24-13, 07:12 PM
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Okay here is where I stand. I got the clear drain tube and white pvc tube disconnect, took the shop vac and stuck it on the end of both of those. Not much came out of the PVC pipe, but all the water in the clear tube sucked right out and into the shop vac. I took the cover off of the pump and cleaned it out. Put everything back where it was, filled the reservoir up with water and it hasn't pumped any water yet. The run light has not lit up and no water has gone into the clear drain tube yet. I don't know what to do. I can't currently post pictures of it, but it is a diversitech model cp-22 condensation pump if that helps...
 
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Old 08-25-13, 04:30 AM
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You originally mentioned that you were seeing water underneath your furnace. It isn't clear to me whether you think the water is coming from the pump overflowing, or if it's coming from the evaporator drain pan overflowing. Here's a quick way to tell. Put a small container underneath the pump so that if it overflows, the container will catch it. If you can't do that, put a piece of paper underneath the pump. If the pump overflows, the paper will get wet. If the evaporator drain pan is overflowing, you likely shouldn't see water underneath the condensate pump, unless your floor slopes so that water underneath the furnace runs toward the pump.
 
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Old 08-25-13, 06:02 AM
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Yes the water is underneath the furnace. The pump is full of water but I do not see where it would be running out of the pump, so it must be from that evaporator drain pan - which I do not know where that is. I opened up my furnace and I could not see anything that would help. Also, the pump hasn't pumped out any of the water, the run light hasn't come on again.
 
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Old 08-25-13, 06:06 AM
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Also, if it is the evaporator drain pan that the water is overflowing from, what do I do for that? Regardless the pump should still be pumping out the water that is full in it shouldn't it? I really don't want to call someone to come out and charge me who knows how much, but I want to get this figured out asap.
 
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Old 08-25-13, 06:51 AM
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Since the water under the furnace appears not to be coming from the condensate pump, it is likely the evaporator drain pan overflowing. The usual cause of this happening is the condensate pipe (white plastic pipe) is plugged. If the water can't drain out of the pan quickly enough, it will overflow. The evaporator pan is where the white plastic pipe goes into the furnace. The pipe attaches to the drain pan. As the condensate drips off the evaporator coil, it begins to fill the pan. When the water level reaches the level of the pipe, it drains through the pipe into the condensate pump. When the pump reservoir fills up, the float rises and turns on the pump which pumps the water out through the clear plastic tubing.

If you want to check the pump, carefully pour water into the inlet opening (you may need to use a small funnel). If the pump is working properly, it should start pumping out the water before the water level rises enough to overflow the pump. Hopefully, when you took the cover off the pump to clean it, you didn't damage the float assembly, as that's what turns on the pump.

If you want to check the evaporator drain pan, look to see if there is a removable cover above where the plastic pipe goes into the furnace. This is the area where the evaporator coil is installed. Not every installation has access to the evaporator coil, but many do. If you can gain access to the coil & drain pan, you can try pouring water into the pan and see if it goes out the white plastic pipe into the pump. If you can get to the drain pan, it probably wouldn't be a bad idea to put a little bleach in the pan to kill any "gunk" that's growing in there and possibly clogging the drain pipe.
 
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Old 08-25-13, 07:06 AM
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I am going to try to get access to the evaporator pan. I already filled up the pump with water last night and it still hasn't pumped any out. That's why I thought the pump might be shot. Like I said, the power light is on and the run light came out for about 5 seconds last night and pumped water out, and then it hasn't come on again since.
 
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Old 08-25-13, 08:16 AM
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The pumps I have seen normally don't activate until around 2 1/4" of water are in the tank and turn off when less than 1 1/4" of water is in the tank. The pumps usually have another light that activates when it goes in to alarm at a certain level. Each pump is different. If your drain is working and flowing properly your pump should never turn on. There is a float inside the pump that controls operation of the pump.
 
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Old 08-25-13, 10:31 AM
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So I filled up the pump with water and moved it around a little and the run light came on and pumped the water. Then I refilled it to the top again and filled it up with water and it did nothing. So I kind of tilted and moved the pump around and the run light came on and it pumped again. Any idea why it does it when theres movement but when I just fill it up and do nothing it doesn't pump?
 
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Old 08-25-13, 12:14 PM
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It sounds like the float mechanism may have gotten moved slightly out of place and the float isn't "floating" up properly. I would suggest taking the top off again and checking the float mechanism to see if the float is binding on something. Once you take the top off, you should be able to work on it in a more convenient location (kitchen countertop). Pour water into the reservoir and see if the float comes all the way up (you may hear a slight click as it trips the switch), or if it's getting caught up on something.
 
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