Ducts to fresh air

[Eragorn Northe]

how would you describe this,

on the outside is a cold air register cover, on the inside this line extends from the duct line of the furnace

Im thinking that this was to bring fresh air into the home?

this line extends to the exterior right above a dryer vent

The dryer vent is to close to the supposed fresh air vent, as fresh air vents in our area usually have a different cover when outside, not an interior cold air return register cover, which is pictured and was under an over hang on a house resently inspected.

according to the N.B.C. outside air is supposed to be brought in to the main pleum, and not to a distribution duct, as done in the picture.

Thanks

[KEVIN WOOD]

The dryer vent is to close to the supposed fresh air vent.
The fresh air vent should be below the dryer vent and 6 feet away.

There are rules as to proper locations, size and installation.
That being said first thing is to check the distance for exhaust of the dryer.
6 feet apart is considered OK by F326, but I recommend if possible to not be on the same wall.
Every IAQ inspection that had crossover happening was always on the same wall and affected the health of individuals.

[Robert J. OConnor]

Is that fresh air intake connected to a return duct (e.g. drawing air in from the furnace blower), and what is the clearance between the intake and the dryer exhaust?

[Jeffrey R. Jonas]

Originally Posted by roconnor

Is that fresh air intake connected to a return duct (e.g. drawing air in from the furnace blower), and what is the clearance between the intake and the dryer exhaust?

It looks as if it is, and I believe that is Eragorn's concern. It it allowed to be a direct connection? Also, is it allowed in Canada, where Eragorn is operating?

[Eragorn Northe]

Originally Posted by roconnor

Is that fresh air intake connected to a return duct (e.g. drawing air in from the furnace blower), and what is the clearance between the intake and the dryer exhaust?

there is no clearance, one is ontop of the other

[Robert J. OConnor]

Originally Posted by jjonas

It looks as if it is, and I believe that is Eragorn's concern.

Looks like a pretty small duct for a typical residential return, unless there are multiple returns, which is why I asked. If it's drawing in air from a furnace blower it's more of a concern.

[Eragorn Northe]

I picked this one out because it was out of place, and the exterior of the duct had an interior register cover on it.

[KEVIN WOOD]

Erogorn:

According to what you have stated this will not provide the added ventilation to all rooms. It needs to be changed to a proper hood and designed supply by a Certified Installer and designer of residential ventilation following the F326 not the NBC.

[Terry Clayton]

Eragron, Your original post states in the last line that it is a distribution duct not a return duct is this correct, if so they would be pushing conditioned air outdoors, the 1st picture appears to have a boot on it like a floor register might have is this correct. I will have to talk with an HVAC guy I know, I am at a loss with the need to introduce fresh air directly into the duct system, would not fresh air be provided to increase the requirements for the combustion appliances, if your are introducing fresh air directly into a system this (my thinking) changes the performance of the system as designed, it has been a ruff day maybe I am just not getting the picture correctly, thanks.

[Eragorn Northe]

Originally Posted by tclayton

Eragron, Your original post states in the last line that it is a distribution duct not a return duct is this correct,Yes if so they would be pushing conditioned air outdoors, the 1st picture appears to have a boot on it like a floor register might have is this correct.Yes I will have to talk with an HVAC guy I know, I am at a loss with the need to introduce fresh air directly into the duct system, would not fresh air be provided to increase the requirements for the combustion appliances,Should be if your are introducing fresh air directly into a system this (my thinking) changes the performance of the system as designed,Yes it would it has been a ruff day maybe I am just not getting the picture correctly, thanks.

go home relax, thanks for the post.

[Robert J. OConnor]

Canada has requirements for mechanical ventilation of houses, which means that outside air needs to be brought into the house. If there is a ducted heating system the outside air (make-up air) is typically mixed with return air to provide the ventilation. However that can also pressurize a house leading to interstitial condensation problems. So there needs to be provisions for exhausting some indoor air also.

It's possible that to relieve some interior pressure, they connected a small exhaust duct running to the exterior off of a heating supply trunk. Which is why I asked if that was connected to a return duct. If it's a relief duct there would be no clearance issues with the dryer exhaust.

Originally Posted by enorthe

according to the N.B.C. outside air is supposed to be brought in to the main pleum, and not to a distribution duct, as done in the picture.

Is that a return duct that is tapped to bring in outdoor air? Or is air brought in somewhere else, and that is a relief duct?

P.S. If the prescriptive requirements of the Canadian NBC for mechanical ventilation are followed, then a site specific design following the more technical CSA F326 performance standard is not required.
.

[Pasquale Giovane]

needs to be connected to the return duct and needs a motorized damper that opens when the furnace fan turns on this lQQks to be a home made make shift duty cycler

[Eragorn Northe]

thanks for the link, Robert

[ROBERT V. YOUNG]

Originally Posted by roconnor

Canada has requirements for mechanical ventilation of houses, which means that outside air needs to be brought into the house. If there is a ducted heating system the outside air (make-up air) is typically mixed with return air to provide the ventilation. However that can also pressurize a house leading to interstitial condensation problems. So there needs to be provisions for exhausting some indoor air also.

It's possible that to revieve some interior pressure, they connected a small exhaust duct running to the exterior off of a heating supply trunk. Which is why I asked if that was connected to a return duct. If it's a relief duct there would be no clearance issues with the dryer exhaust.


Is that a return duct that is tapped to bring in outdoor air? Or is air brought in somewhere else, and that is a relief duct?

P.S. If the prescriptive requirements of the Canadian NBC for mechanical ventilation are followed, then a site specific design following the more technical CSA F326 performance standard is not required.
.

Thanks Robert

[KEVIN WOOD]

Robert:

If they did, that is about the dumbest thing I have ever heard.

It's possible that to revieve some interior pressure, they connected a small exhaust duct running to the exterior off of a heating supply trunk. Which is why I asked if that was connected to a return duct. If it's a relief duct there would be no clearance issues with the dryer exhaust.

I got a good idea! Lets heat the patio with some of the supply air from the furnace. That should cost very little since it is only a small 6 inch duct blowing at 100 cfm.

I would love to see there heating bills in MooseJaw.