How much condensation is normal? Colorado, 92% Heil furnace

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Old 05-02-13, 03:12 PM
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How much condensation is normal? Colorado, 92% Heil furnace

I've just gone into my utility room and noticed a huge puddle on the floor around the furnace, and water dripping from the condensation PVC pipe (that was plumbed a bit too far from the drain apparently, hence the puddle. That's easily resolved)

But I'm curious how much condensation is normal? It's a pretty steady drip drip drip, I'd guess 8 ounces a day easy. Is this normal? I'll fix the PVC drain promptly and dry off the bottom of the furnace. But I want to see if anyone thinks this indicates a problem. I noticed last month that the direct vent outside was pretty humid air, too when I threw a bird grate on it.
 
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Old 05-02-13, 04:06 PM
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The amount of condensate generated depends on how humid the air you are cooling. A cup (8 ounces) a day is nothing.
 
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Old 05-02-13, 04:22 PM
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Understood, except this is Colorado and the humidity level is perty darn close to nil That's why it surprised me.
 
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Old 05-02-13, 04:26 PM
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The more moisture your furnace condenses out of the exhaust, the better.

Condensing water vapour in the exhaust into liquid water releases additional heat which warms your home. (the proper term is latent heat - google it if interested) That's what makes your furnace 92% efficient; otherwise it would be in the mid to high 80s at most.

They don't makes furnaces between 80 and 89% efficient to avoid condensation in the exhaust, whereas 90%+ condensing models actually are designed to handle the condensation.

The moisture in the exhaust is produced by burning gas; it doesn't come from the indoor air.
 
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Old 05-02-13, 08:24 PM
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Muggle has this one! Furd was referring to cooling and not heating.
 
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Old 05-02-13, 09:35 PM
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Thanks for the lesson - I'm glad it's nothing to be concerned about.
 
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Old 05-02-13, 10:08 PM
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Muggle has this one! Furd was referring to cooling and not heating.
Yes, I sure was! Most of the posts lately have been A/C related and I thought this was just another. If I remember my chemistry for every two molecules of methane (natural gas) burnt you get a molecule of water so even in mild temperatures you can get a significant amount of condensate from a 90+% furnace.
 
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Old 05-20-13, 07:41 AM
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Reverse that, it's actually 2 water molecules per 1 natural gas molecule

Methane's chemical formula is 1 carbon, 4 hydrogen.
Burning the carbon taxes 2 oxygen atoms, burning the hydrogen takes 2 oxygen atoms.
End result is the four hydrogen are used in two water molecules.

Weird thing, burning 16 pounds of natural gas actually produces 36 pounds of water.
The added weight actually comes from the air.

Atomic hydrogen weights 1, carbon 12, oxygen 16.
So, burn sixteen pounds of Natural gas ([email protected] + [email protected]) and those 4 hydrogen get incorporated into 2 water atoms, ([email protected][email protected]) resulting in 36 pounds of water. So, 40 lbs cylinder of natural gas would burn to create about 90 lbs of water.

You also get 46 lbs carbon dioxide per 16 lbs of natural gas if the furnace is burning correctly.
If you get half burned carbon, e.g. carbon-monoxide, that would be 30 lbs of carbon monoxide lurking around waiting to finish the "burning" process by grabbing 16 lbs of oxygen where ever it can find it - usually from the oxygen in your body and red blood cells.
 
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Old 05-21-13, 02:40 PM
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Very hard to say!!!!!!!!!!!!!!!!!!!!!!!!
 
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