Question about negative pressure


  #1  
Old 08-03-05, 09:06 AM
hlweyl
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Question about negative pressure

Hi all,

I did a search and read through many threads, but I couldn't find an answer. I recently finished my basement and originally there was only one vent. The finished basement area is not that large so I thought adding only one other vent in the main trunk would suffice. I also talked to a friend of a friend who does HVAC for a living and he said that would be fine but I should consider adding a return down on the floor level so I did that.

I also checked out a neighbor's house who has the same house with a finished basement done originally by the builder and they had 6 vents and I believe 4 returns with the same model furnace that I have.

Here's my question: should I have added the return? There is serious negative pressure in the room now. I know this because when I am walking up the stairs, you can feel serious air pumping in through the basement door(there is a cat door cut in the bottom of it). Even when I seal the return up, there is still some negative pressure.

I heard this can be dangerous because the negative pressure can such carbon monoxide through the gas vent pipe on the hot water heater. Should I be worried about this?

Thanks in advance
 
  #2  
Old 08-03-05, 10:44 AM
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I'd check the return duct in the basement and see if there holes that was missed to tie into a return for a room upstairs.. I've found this a couple of times in the past where someone forgot to the panning for returns.

Also check end of the return runs to see if caps were put on. and joints are joined together.
 
  #3  
Old 08-04-05, 01:20 PM
hlweyl
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I checked and all the returns from the two floors above are connected. Is this negative pressure condition normal or dangerous?

Thanks
 
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Old 08-04-05, 01:57 PM
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I don't think it's normal to have that much draw if you already don't have returns down there.. It's leaking somewhere... Best test to do is take a match and put it next to the vent hood that ties the water heater and/or furnace and see if your match blows out or smoke sucks up the hood.
 
  #5  
Old 08-04-05, 07:28 PM
hlweyl
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I put some smoke next to the hot water heater's vent and it was sucked up easily. Now I know that vent doesn't run full time but I'm assuming it is doing it's job when it's on.

So I guess I will leave the basement return sealed up at this point.
 
 

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