HVAC installer never connected the condensate pump's safety/overflow switch to the AC unit.

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gfw

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So, my understanding is that if the condensate pump fails and fills up, this switch should tell the AC to stop running. How critical is this? It seems like all that would happen is the pump reservoir would overflow, but it's possible that water could get into something important.

There is a controller for the AC near the pump - it's obviously the controller since it has wires to the thermostat and the ventilation timer. It's hard to see in there, but the back of that controller might have a couple of wires sticking out, not attached to anything. Is that likely where the condensate pump safety switch should be connected? Is there any way to be sure?
 

Jeff Handy

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Stop trying to answer your own question!
Are you here for help, or for some other reason?

The overflow float sensor stops the AC from creating condensate that causes flooding and water damage.
 

gfw

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> The overflow float sensor stops the AC from creating condensate that causes flooding and water damage.

Was it not clear that I already know this? The real question is

> Is that likely where the condensate pump safety switch should be connected? Is there any way to be sure?
 

Jeff Handy

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Yes, connect the wires, turn on the AC, lift the overflow float all the way, the AC should turn off.
 

gfw

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To which wires on the controller (there are three unconnected ones, blue, red, black) do I attach the white leads from the pump?SAM_3839.JPG
Or do I connect the white leads to somewhere else? This is the information I'm missing, since the original installer didn't bother to do it.


(edit) - Ah, I think you're suggesting that I just try the wires by manually testing the switch. If I have the right wires, the AC will shut off. Agreed. But is there any danger of me damaging anything by guessing wrong?
 
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kok328

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Yes, you could potentially damage something if your not sure what your doing and just start hooking up wires at random.
I would want to see a wiring diagram for the furnace and the condensate pump before providing any advice.
Most likely we're just going to interrupt the control power to the entire unit to shut it down.
 

Jeff Handy

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Call whoever installed the condensate pump and controller, have them hook it up.

Or look for brand and model number on that controller, there is likely a wiring diagram online.

I think you said the controller is already wired into the furnace controls, right?
 

gfw

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Yeah, I emailed the installer on Monday. Trouble is, they installed it 12 years ago and probably don't want to admit they screwed this up. I've just emailed again.
I'm lucky that the pump lasted this long and then failed at a point in time when I would notice before it became a problem.
I don't see a brand & model on the controller, but maybe I can find some info in the paperwork from 12 years ago.
 

Jeff Handy

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I think you never stated that your condensate pump had failed.

You just said “if the condensate pump fails and fills up”.
 

kok328

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Ok, so if your going to replace it, follow the new pump installation instructions, it will tell you where to land the wires from the pump onto the unit.
 

EdInKentucky

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GFW ... whether or not to use the overflow protection device in the pump ... depends on where the pump is.
My experience is to not use the device (leave the wires disconnected) if the pump is in a place where some water getting onto the floor, won't cause any damage (a basement near a floor drain or sump pump pit).
The main reason for this is .. if the overflow device is hooked up and in use, it will stop the AC unit when there is an overflow. Then, you will probably call the AC repairman and incur at least a $100 service call charge, plus any work they need to do.
So ... I'd say only use the overflow device if the overflow will actually causes some damage.
best regards
 

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