Is this fresh air intake up to code?

I’m just wondering is there a code for fresh air intake to be filter before going through the air handler? I am trying to figure this out so i can tell builder to install a filter on my fresh air intake. Only if it’s not up to code do i think they will fix this issue. If not they just gonna leave it as is and that’s not good. You can see in the pictures what i am talking about. Fresh air goes Straight to return plenum then to furnace no filter between them. Ac filter are 1x in living area. Thanks!

http://www.nachi.org/forum/http://i57.tinypic.com/6rn67s.jpg

http://www.nachi.org/forum/http://i59.tinypic.com/ermqtz.jpg

Fresh air is for the flame .
Pictures not showing.

Is it a schedule 40 air intake on a category 4 furnace you are refering to ?

There is no requirement for there to be a filter in the code that I’ve ever seen. Even the ASHRAE standards don’t address this. Some manufactured homes have a small filter that only filters out large debris. You could probably find a HVAC contractor to put in some brackets to hold a small 12x12 filter or something like that.

[quote=“johnny_le, post:1, topic:100455”]

I’m just wondering is there a code for fresh air intake to be filter before going through the air handler? I am trying to figure this out so i can tell builder to install a filter on my fresh air intake. Only if it’s not up to code do i think they will fix this issue. If not they just gonna leave it as is and that’s not good. You can see in the pictures what i am talking about. Fresh air goes Straight to return plenum then to furnace no filter between them. Ac filter are 1x in living area. Thanks!

http://www.nachi.org/forum/http://i57.tinypic.com/6rn67s.jpg

If as you say exterior air is being drawn in to the return air plenum downstream of the interior return air filters, its wrong but I know of no code that restricts this. My question would be why are you introducing outside air into a closed loop system. Are you getting confused between combustion air for the burners and return air for the home. Most areas of the US do not add make up air into the return unless you have a totally sealed home attic included.

Alberta (Canada) code requires fresh air for ventilation (AND combustion air unless the appliance is direct vented).

All new homes built since about 2000 have to have a mechanical air make up system consisting of exhaust and fresh air intake. The cheapest and most common method brings fresh air into the return air system upstream of the furnace air filter, a bath exhaust handles the exhaust side, a central control operates the exhaust fan and furnace fan together. Next most common is an HRV unit with its own filters.

No filters would be a problem, especially in a new home development where there is plenty of dust and dirt.

Alberta’s climate is similar to ND SD MT etc… Nobody is going to open a window in January, and new homes are built tight for energy efficiency. It would not surprise me to find mechanical air make up being used by home builders North Central US as well.

It is not uncommon around here for outdoor air to be tied directly into the return air drop. Typically it is done for two reasons. The first is to control infiltration. Tying outdoor air directly into the return helps prevent frosting and condensation around windows and doors. The second is to help prevent the spread of colds, flu, etc. Besides for normal door opening and closing, our houses are closed up from November until March or April.

A damper is tied into the call for heat. It is not as good of a system as an ERV, but a fair amount of people do not want to put that much money into it.

I can understand that but you guys up north live in a different world maybe even on a different planet;-):D. Down here outside air into the return is only required on commercial buildings and that is only 10% . I guess we are to tight down here to want to pay for cooling and or heating non-conditioned air in our homes

I had one commercial space that was in such a negative pressure that the front door froze shut from infiltration. A 6" outside air tied in the return solved it.

One of the service techs that I used to work with came up from Enid. It took him a bit to get used to the different way of doing things. He was always “fixen” do do things. Whatever the hell that means???

When he first arrived, heat pumps were just starting to really take off around here. Some of the seasoned techs were totally against them. Even with classes, they refused to see that they are really not that hard to figure out. It was just taking them outside of their comfort zone. It took him showing them in the field that they were not to be feared.

I remember when standing pilots were becoming extinct. One of the techs was so set in his ways that he refused to keep up with new technology. If it did not have a T87 stat and a standing pilot he did not want have to deal with it. It did not take him long to change professions. I am pretty sure I saw smoke coming out of his ears when I sold a job with multi zones and twinning kits.

Fixen is what we do to cats and dogs and some people:mrgreen::wink:

What he’s asking about is not combustion air. He sates it’s in the return plenum. This is to provide mechanical ventilation for the home. The IRC and Mechanical code require ventilation air for any home under 5 ACH. The 2012 and later IECC requires mechanical ventilation also. This is just one of several ways that this requirement can be meet. It meets code which is a minimum and doesn’t require a filter.

If you’re talking about the air return that goes into the furnace, it would be good to have a filter otherwise you would be breathing dirty air cycled through the the home.

Combustion air should not have any filter or louvers as it will immpead air flow.

Charley,

Here is an example of this system. This was on a brand new home.

There is nothing wrong with connecting the outside combustion air source to the cold air return.

Think about it.

This is “fresh air” or “outside air”, not combustion air.

Is there a gas fired water heater?

Even if not, where do you suppose the air comes from to replace air exhausted by range hoods or bath fans?

You install the fresh air intake in the same manor as you would for an HRV or ERV. It should be installed on the opposite exposure as what you listed. Also the same thing as the gas meter.

Not sue what you are saying.

Please explain what is wrong with install a fresh air intak into the cold air return.

Its a very common installation.

And what does it have to do with a gas meter?

I agree with you that there is nothing wrong with pulling outside air into the return air. What I am saying is that for it do be done properly, you do not want the intake next to any exhaust or next to the vent on a gas meter regulator.

I agree completely. Thanks for clarifying.:smiley:

Big difference in different parts of the country I see maybe 1 in a thousand homes that actually has outside air introduced into the return air system. The standard central system in Okla is strictly a closed loop. We don’t use the words (cold air return) because the return air is not cold it is room temp, supply air is cold not return air. :mrgreen: We don’t use outside air in the return the A/C units are not sized for the extra temp load introduced into the system as non-conditioned air. In Okla it was always determined that the normal opening and closing of the exterior doors provided a proper air change within the home. As construction material changed over the years and homes have less air loss and gains it will probably become more dominate in Okla to see outside air introduced into the return but it has not happened so far. That is my story and I am sticking to it:D