# AC fix.......condensate pump wiring



## HVAC1000 (Dec 12, 2012)

busboy said:


> Hi All, new member. My condensate pump just packed it in, waiting for a new one now. Since removing the old pump my ac unit doesn't seem to be cooling the house like normal. The old pump was hard wired to the furnace electrical board, I see the new ones come with wall plugs. Is there a circuit in the furnace that I need to connect to get the ac working again? Are they even related? Never had to work on this before, just looking for some cool air again.


We used to always cut off the wall plug and hard wire it into the air handler supply voltage. But modern code (at least around here) says we need to install a GCFI and plug it in or we won't pass inspection. Your unit isn't cooling because it may be wired thought the pump so that if the pump doesn't work it will interrupt the contractor wire. It should just be spliced in at a simple 2 wire on the pump, separate from its high voltage supply.


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## old_squid (Oct 31, 2012)

Did the pump you removed happen to have two wires coming out of it at a location other than the electrical cable that was wired to the board?

If it did, this is a safety switch to turn off whatever is connected to it if the water level in the tank of the pump gets too high. It sounds as if your pump might have had this safety and it was wired to control the outdoor condensing unit. If so, put the two wires that went to the pump's wires together (with a small wire nut) and see if your outdoor unit starts running again.

If you're not 100% sure of what you're doing or are afraid of working on electrical, post a picture of old pump and connections that went to it.


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## busboy (Jun 25, 2013)

Thanks for the replys. The old pump has two small wires coming off the float switch, the white one is hard wired into the winding first then comes back out as a loose end, the black one is a loose end. There is a green/yellow one coming off the body of the pump (loose end) The main power cable into the furnace is metal sheathed and has three wires, a black, a white and a copper ground wire. There were three small marrettes wiring everything together when I took it apart.


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## old_squid (Oct 31, 2012)

As I read your response I'm "seeing" only 3 total wires on that pump and I'm assuming from the description that you're describing what is normally hidden inside the pump's housing and also what comes to it from the furnace.

Doesn't sound like there is an auxiliary safety float in the pump that would or could have been wired as a low voltage safety switch originally. 

Why your AC isn't cooling the house sufficiently I'm going to guess at this point has nothing to do with the pump. Did you notice the lack of cooling first and then found the bad pump? If that is the case you've got more than one problem. Problem one being the pump, problem two having something to do with the AC unit itself.

Make sure the air filter is clean/new.
Check the outdoor unit for dirt, pollen or some other form of debris that may be blocking air flow through the outdoor coil.
Make sure all registers, both supply and return, are fully open and unobstructed.

If all the above is fine and the outdoor unit and indoor unit is running normally (as best as you can determine from experience) then it's time to call in a service tech. to locate your trouble.


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## busboy (Jun 25, 2013)

Thanks squid. You are correct, only 3 wires on that pump, that's what I saw when I removed the housing. The cooling was working fine, we've only had it on a few times this year, I found out the pump wasn't working when that corner of my basement flooded. I like your thinking about a multiple failure. 
I had a look at the outside cooling unit last night, it's clear of debris and humming away like normal. Filter is a good call, I'll check that tonight when I get home. The upper structure of the furnace is plenty cool to the touch, seems like that flow just isn't making it to the rest of the house. Does the cold air go through the HVAC (air exchange unit)?? A few years back one of the fans in there packed it in and the house got pretty stuffy until I figured out what it was. I'll check that as well tonight.


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## busboy (Jun 25, 2013)

Ok, got the new pump today, a Little Giant. It has two black wires running off the safety switch. Instructions say it should be connected to a Class II low voltage circuit (115????). The wiring for the old pump, coming out of the furnace, has a black and a white wire and a ground. How do I wire this up? I'm not an electrician and would really hate to blow something.


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## busboy (Jun 25, 2013)

Any help much appreciated.


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## hvac122 (Dec 10, 2007)

That would be to break the 24v circuit going outside in case the pump quits it would shut off your air conditioner. Usually the y wire going outside.

Sent from my iPad using DIY Forum


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## HVAC1000 (Dec 12, 2012)

hvac122 said:


> That would be to break the 24v circuit going outside in case the pump quits it would shut off your air conditioner. Usually the y wire going outside.
> 
> Sent from my iPad using DIY Forum


He's right splice it in series with either of the wires going out to the condenser so it can break the circuit is needed


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## busboy (Jun 25, 2013)

Thanks for the reply's. I got myself a small low voltage transformer, mounted it to the side of the furnace and wired it all up. The condensate pump is working fine so my flooding issue is taken care of, the a/c is working again although not quite as cold as I remember so I'm still trouble shooting. The upper portion of the furnace "body" is very cold to the touch but not much seems to be getting past that. The journey continues!


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