Outside fresh air pipe - needed in summer?


G

geberly

I live in Virginia in a house built in 2002. I have a 6" pipe that
runs from the outside to my cold air return. I have a propane
furnace, but it is not the high efficiency kind that require a
separate line into it for combustion.. I can kind of see a reason to
have this in the winter time, but in the summer is it really
necessary? Also, my 6" pipe is located about 2 feet from my outside
AC unit. When I was having my routine maintenance done, the AC guy
commented on the horrible location saying it would be pulling in even
hotter air with that location. I would love to seal it up during
the AC season, if possible.

Speaking of return, how do they check to see if the return ducts are
pulling air adequately? I know nothing about HVAC systems, but it
seems to me the last intake location in my house is not doing much.
 
G

Guest

I live in Virginia in a house built in 2002. I have a 6" pipe that
runs from the outside to my cold air return. I have a propane
furnace, but it is not the high efficiency kind that require a
separate line into it for combustion.. I can kind of see a reason to
have this in the winter time, but in the summer is it really
necessary? Also, my 6" pipe is located about 2 feet from my outside
AC unit. When I was having my routine maintenance done, the AC guy
commented on the horrible location saying it would be pulling in even
hotter air with that location. I would love to seal it up during
the AC season, if possible.

Speaking of return, how do they check to see if the return ducts are
pulling air adequately? I know nothing about HVAC systems, but it
seems to me the last intake location in my house is not doing much.

What did your service guy say?

What's your reasoning for having it in the winter?
 
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G

geberly

What did your service guy say? The service guy said that was a crazy
location to have an air intake pipe.

My reason for having it in the winter? Here is my uneducated guess:
In a newer house, it is going to be (hopefully) sealed pretty well.
With the furnace using combustion, it seems plausible that grabbing
air from the outside would help supply any extra air for that and
would stop any drafting around the house.
 
G

Guest

What did your service guy say? The service guy said that was a crazy
location to have an air intake pipe.

I read that, I meant as far as closing it off.

My reason for having it in the winter? Here is my uneducated guess:
In a newer house, it is going to be (hopefully) sealed pretty well.
With the furnace using combustion, it seems plausible that grabbing
air from the outside would help supply any extra air for that and
would stop any drafting around the house.

Pretty good... now sitting at my computer, I'd say close it off in the
Summer. But this doesn't allow for a fresh air intake that could lead to
indoor air quality issues.
 
G

Guest

Jeffrey Lebowski said:
Safety issue not comfort.

It's not really a safety issue... the equipment room should still have the
required combustion air intake.

Respectfully disagree, and venture that almost certainly would be against
code...

Your suggestion is nice, however, IMC doesn't require make-up air in a
residence.
 
A

Abby Normal

I live in Virginia in a house built in 2002. I have a 6" pipe that
runs from the outside to my cold air return. I have a propane
furnace, but it is not the high efficiency kind that require a
separate line into it for combustion.. I can kind of see a reason to
have this in the winter time, but in the summer is it really
necessary? Also, my 6" pipe is located about 2 feet from my outside
AC unit. When I was having my routine maintenance done, the AC guy
commented on the horrible location saying it would be pulling in even
hotter air with that location. I would love to seal it up during
the AC season, if possible.

Speaking of return, how do they check to see if the return ducts are
pulling air adequately? I know nothing about HVAC systems, but it
seems to me the last intake location in my house is not doing much.
Well, from my experience in a humid climate, if you could put a damper
in that intake, it could help lower the humidity in your home.

For it to work, you are going to have to have the furnace fan in the
"Auto Mode" so that it just runs when the compressor runs.

What will happen is that whenever the AC runs, some fresh air will get
drawn in directly to the AC system. The heat and humidity of this air
goes right to your cooling coil, and you end up pressurizing your home
with dry air. Dry air will try to leave your house rather than warm
humid air infiltrate into your house.

You would adjust the damper and open it up enough so that when the AC
was running, you could just notice cool air leaving from a door that
was cracked open.

If your house leaks like swiss cheese it will not work, but if it is
reasonably tight it could work great.

You cannot run your fan all the time, otherwise you will be pumping
humidity into your house when the compressor is off.
 
G

Guest

Jeffrey Lebowski said:
lead

Not sure why it was done ( with timer and damper as described above ) at my
brothers place then.

It might very well be a local code.
 
A

Abby Normal

You are paying to heat it one way or the other. Either let it
infiltrate in uncontrolled or bring the air in, in a controlled manner
and condition it first.

In cooling if the house is reasonably tight, no air will be
infiltrating in when the system is running. Probably 0.05 CFM fresh
air per sqaure oe less, would stop summer infiltration.
 
A

Abby Normal

So I guess an air-to-air heat exchanger would be abby-normal?
No, an HRV or an ERV could give you plenty of ventilation. The problem
is they are supposed to be a neutral pressure ventilation system, so
natural infiltration still occurs.

What I am talking about, in cooling is a one sided ventialtuion
scheme. Deliberately draw in the fresh air, cool and dry it, and
pressurize the home. Stops infiltration.

On a commercial building you can run big ERVs out of babalnce to
pressurize, the residential ones, if you run them out of balance they
do not really save you much on the load.

Silght pressuizing in the cooling season, can stop infiltration and
lets you directly deal with the humidity in the outside air.
 
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F

ftwhd

IMC requires combustion air for commercial systems.
Some residential codes may require it as well.
I use them everywhere, unless an ERV/HRV is installed.
Here in MN. I've seen lots of them drop down the wall into a 5 Gal. bucket
or looped back up to act as a P-trap & stop cold winter air from flooding
in. Direct into the return works as well, but if it faces north or west,
runs the risk of winter winds blowing into the return, etc...
Dampering is a possibility, but a gas dryer, stove, or water heater will
need the combustion air year round.
If all of the units are on full fire, the fart fans & kitchen hood are
running, you can backflow the flue gasses & make the whole family sick...
We had a case here last fall of a home owner that installed his own boiler,
bought direct from local wholesaler.
Cops pulled him over thinking he was drunk, took him in for tests & released
him...
He went back home & woke up sick with a family member dead of CO...
Sparky needs a license to wire a panel, but gas lines are anybody's
business?

goodluck
geothermaljones
st.paul,mn.
Thats damn sad and even more reason not to enable these hos with info.
A few tid bits and they think thats all there is to it and that we are
rip offs and con men for charging too muchie.

Failing to see the bigger pitchure they unwittingly make a choice
between the local undertaker or hvac company.
 
G

Guest

daytona° said:
Hey guy.....where are you. We give all these recommendations, at least you
can come back and acknowledge one of them

He replied to me once.

I guess he didn't want to talk to the rest of you Bozo's! :)
 
A

Abby Normal

Combustion Air

Ventilation Air

Make Up Air

Three related but separate issues. Should not rely on one system to do
more than one of those tasks. In some places a fresh air duct to the
return would not be deemed as providing combustion air.
 
G

Guest

Abby Normal said:
Combustion Air

Ventilation Air

Make Up Air

Three related but separate issues. Should not rely on one system to do
more than one of those tasks. In some places a fresh air duct to the
return would not be deemed as providing combustion air.

Especially when the combustion air is to be ducted into the equipment room.
 
G

geberly

Thanks for the replies. I replied to the last post I saw and did not
get to check this site for the last 20 or so hours.

Based on what I have read, I think I will close up the pipe some
during the AC season. The pipe is a 6" flexible one so I don't see
how I can put in a lever in it. I will likely just go to where it
connects to the outside of the house and try to block half the intake
and then adjust as necessary.

For what it is worth, I thought I was posting to a general HVAC
question board (for hacks) and did not realize it was basically for
professionals. Thank you for your time.
 
R

Rick Blaine

For what it is worth, I thought I was posting to a general HVAC
question board (for hacks) and did not realize it was basically for
professionals. Thank you for your time.
Despite what several frequent posters here seem to think, alt.hvac is NOT just
for self appointed pros. From the alt.hvac charter, last updated in 2005:

alt.hvac is an un-moderated open public forum about the discussion of
Heating, Ventilation, Air Conditioning. (HVAC). This forum is available to post,
read and participate by any and all individuals, groups, homeowners, renters,
maintenance personal and professionals of the industry.

There is/was a group called alt.hvac.pro-series.moderated, but it seems to be
dead. Not surprisingly, I guess...
 
G

geberly

I stand corrected. I checked the dates on the threads, and evidently
I waited almost 2 days to respond (even though I'd swear in court I
posted this Friday afternoon.) Sorry about that. I must have been
in a daze all day Friday not to check the thread.
 
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A

Abby Normal

I stand corrected. I checked the dates on the threads, and evidently
I waited almost 2 days to respond (even though I'd swear in court I
posted this Friday afternoon.) Sorry about that. I must have been
in a daze all day Friday not to check the thread.





- Show quoted text -
I think you may have accidentally changed the title of the thread
 

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