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Inspecting HVAC Systems Topics include heating, venting, and air conditioning inspections.

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  #1  
Old 8/3/06, 10:55 AM
Andy T. Bishop Andy T. Bishop is offline
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Default Condensation drain vent

Got a question about the vent off the condensation "T" while running the Central Air. How much air should be coming out of this?
Got a friend that says his blows quite of bit? New house.
Thanks
Andy B
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Old 8/3/06, 11:27 AM
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roconnor roconnor is offline
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Default Re: Condensation drain vent

Thats probably not a vent on the condensate drain line, and there shouldn't be much air coming out. Should be a tee after a trap (as long as it's not tied into a stack vent ... which shouldn't be done anyway) with a short open vert pipe that comes up above the primary drain pan level as a cleanout. They may have put the cleanout tee before the trap without a loose cap, or not enough condensate is being generated to seal the air flow.



Robert O'Connor, PE
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Old 8/3/06, 2:20 PM
Andy T. Bishop Andy T. Bishop is offline
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Default Re: Condensation drain vent

It is the small 1/2 pvc line that comes out the furnace, tees up and down. Down to drain the condensate and up to vent.
So what you are saying is it doesn't condensate enough? How do you get it to condensate more? Burner/gas setting?
Thanks!
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Old 8/3/06, 2:21 PM
Andy T. Bishop Andy T. Bishop is offline
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Default Re: Condensation drain vent

I will try and get a pic.
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Old 8/3/06, 3:57 PM
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Default Re: Condensation drain vent

Robert is most likely correct, a picture would help
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Old 8/3/06, 7:36 PM
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Default Re: Condensation drain vent

Are all the vents open?

I agree with Bob.
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Old 8/3/06, 9:18 PM
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roconnor roconnor is offline
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Default Re: Condensation drain vent

A pic would be helpful. And are you talking about the condensate drain line for a central air conditioner (my initial reaction) or a high efficiency forced air furnace?

In any event condensate is usually piped to daylight or a plumbing fixture tailpiece (before the fixture trap so sewer gas doesn't come out of the condensate lines ... any why you shouldn't just tap a condensate line directly into a sewer waste sack or vent stack like in an attic). To keep air from blowing out of the condensate lines there is usually a trap in the line. It's not required to vent this trap like you would plumbing fixture waste line traps ... since there shouldn't be the risk of sewer gas backing up through the lines, and there generally isn't enough flow/pressure to suck the condensate trap dry.

Although it's not required, many consider it good practice to install an open or removable section of pipe that comes up from the condensate line in order to clean out the lines if they appear to be clogged (aka condensate "cleanout"). This can be an open section of pipe after the condensate trap, or a removable capped section of pipe if it's before the trap. That way conditioned air will not blow out of the condensate cleanout.

So what I think you are describing is actually a cleanout for the condensate lines, and not a vent. And it shouldn't be blowing any air at all with a trap in the line and a correctly installed condensate cleanout.

JMO & 2-nickels ...



Robert O'Connor, PE
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LIU CW Post Adjunct Professor
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www.reporthost.com/-rjo

I am absolutely amazed sometimes by how much thought goes into doing things wrong ...
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Old 8/4/06, 10:55 AM
Andy T. Bishop Andy T. Bishop is offline
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Default Re: Condensation drain vent

Here is the pic. It is blowing quite a bit.
Thanks
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Old 8/4/06, 1:07 PM
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Patrick Bolliger Patrick Bolliger is offline
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Default Re: Condensation drain vent

"Houston we have a problem"

What you got there is a sealed burner "Condensing" Category 4 FAU ... I see a "tee" at the bottom of the "exhaust" that is connected directly into a condensation drain line... Hmmm Think about this .. That pressure is coming from the blower motor out through the "tee" fitting at the top. Why is it done that way???...

This is a case of MFG installation instructions review and possible incorrect installation practice..
I have never seen such a large direct connection from the exhaust to the conensate drain line like that... maybe a small drain tube but never that Huge "tee"...

Anyone.
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Old 8/4/06, 1:59 PM
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Patrick Bolliger Patrick Bolliger is offline
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Default Re: Condensation drain vent

Check this out:
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condensation-drain-vent-furnacventrs.gif  
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