Condensate pump for furnace

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drcampbell

drcampbell

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The Motor City, Michigan USA
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Registered Professional Engineer
hillbilly1 said:
True, but most have a float in the pan to shutdown if pan fills from pump failure.
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There's a float switch in the condensate pump reservoir that will shut down the condensing furnace and air conditioner?

I have never seen such a thing. Just a float switch in the condensate pump reservoir that turns on the condensate pump. (if power's available)
 
H

hillbilly1

Senior Member
Location
North Georgia mountains
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Owner/electrical contractor
drcampbell said:
There's a float switch in the condensate pump reservoir that will shut down the condensing furnace and air conditioner?

I have never seen such a thing. Just a float switch in the condensate pump reservoir that turns on the condensate pump. (if power's available)
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Yes, I think it’s on all the new pumps. There is also one usually on the pan under the unit.
 
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hillbilly1

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North Georgia mountains
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synchro

synchro

Senior Member
Location
Chicago, IL
Occupation
EE
In the winter's here there would be times when shutting off the furnace could have a far worse outcome than with a non-working condensate pump.
 
kwired

kwired

Electron manager
Location
NE Nebraska
drcampbell said:
There's a float switch in the condensate pump reservoir that will shut down the condensing furnace and air conditioner?

I have never seen such a thing. Just a float switch in the condensate pump reservoir that turns on the condensate pump. (if power's available)
Click to expand...
I've been wiring for 30+ years, they pretty much have always had two leads that almost never get connected to anything and a 5-15 cord cap for main power supply. Those two leads are an aux switch to shut down the 24 V controls on your unit if the thing fails pump and is full.
 
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hhsting

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Glen bunie, md, us
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Junior plan reviewer
hillbilly1 said:
True, but most have a float in the pan to shutdown if pan fills from pump failure.
Click to expand...

Wow just knowledge and experience you all have in this forum amazes me. My furnace in my home just now shut off and there was no power to thermostat and thermostat indicated furnace is off, AC off power cut off. Puzzling went down to garage utility room and found something related to this post. None of the breakers were tripped so I checked how my house condensate pump is wired and guess what it does have float switch at the pan bottom furnace where water collects. Sure enough there is float switch switches the furnace off if water collects in the pan and if pump fails or their is leak somewhere that collects water. Amazing amount of knowledge you all have.
 
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LarryFine

LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
I usually wire it to interrupt just the compressor (yellow) wire, not the main (red) wire, as I do with a load-shedding ATS.
 
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hillbilly1

Senior Member
Location
North Georgia mountains
Occupation
Owner/electrical contractor
hhsting said:
Wow just knowledge and experience you all have in this forum amazes me. My furnace in my home just now shut off and there was no power to thermostat and thermostat indicated furnace is off, AC off power cut off. Puzzling went down to garage utility room and found something related to this post. None of the breakers were tripped so I checked how my house condensate pump is wired and guess what it does have float switch at the pan bottom furnace where water collects. Sure enough there is float switch switches the furnace off if water collects in the pan and if pump fails or their is leak somewhere that collects water. Amazing amount of knowledge you all have.
Click to expand...
I've been an electrician for 38 years, and there is always something new to be learned every day! LOL! This forum is a great place to gain collective knowledge!
 
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suemarkp

Senior Member
Location
Kent, WA
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Retired Engineer
LarryFine said:
I usually wire it to interrupt just the compressor (yellow) wire, not the main (red) wire, as I do with a load-shedding ATS.
Click to expand...
My idiot installer put it in the fan wire... It is supposed to go on the red wire -- break power to the thermostat to turn off everything. If you have a 95% gas furnace, they produce condensate as well, so interrupting the compressor wire would not help in that case. I was shocked at how much condensate a furnace can make. When my condensate pump died, I put a 5 gallon bucket by the furnace to catch the condensate. I had to dump it daily and it had about 4 gallons in the bucket.
 
synchro

synchro

Senior Member
Location
Chicago, IL
Occupation
EE
suemarkp said:
If you have a 95% gas furnace, they produce condensate as well, so interrupting the compressor wire would not help in that case. I was shocked at how much condensate a furnace can make. When my condensate pump died, I put a 5 gallon bucket by the furnace to catch the condensate. I had to dump it daily and it had about 4 gallons in the bucket.
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FYI, that 4 gallons represents 4 gal x 8.34 lb/gal x (930 BTU/lb latent heat of condensation) = 31,000 BTU of heat energy that was recovered by the condensation of water vapor produced by combustion.
 
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Mgraw

Senior Member
Location
Opelousas, Louisiana
Occupation
Electrician
suemarkp said:
My idiot installer put it in the fan wire... It is supposed to go on the red wire -- break power to the thermostat to turn off everything. If you have a 95% gas furnace, they produce condensate as well, so interrupting the compressor wire would not help in that case. I was shocked at how much condensate a furnace can make. When my condensate pump died, I put a 5 gallon bucket by the furnace to catch the condensate. I had to dump it daily and it had about 4 gallons in the bucket.
Click to expand...
Usually anything over 90% gas furnace is a condensing furnace and you would need to break the red wire. On a standard furnace(gas or electric heat) or heat pump I would break the yellow wire.
 
kwired

kwired

Electron manager
Location
NE Nebraska
suemarkp said:
How about when there are two compressor stages...
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one is the compressor contactor, the other is a valve in the refrigerant lines, break the compressor control and it won't run at all. Or better yet just break the R conductor to the thermostat and nothing runs anyway.
 
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