HVAC Venting question

I am a new licensed inspector in Ohio. I always check out the daily forum summaries, learn something new daily, and have commented a couple of times but haven’t asked many questions. I know this is beyond the scope of a Home Inspection and certainly beyond the SOP, but trying to learn and understand a little more. Here goes: In an inspection I did the other day I saw the 3 white PVC pipes coming out of the side of the house. I understand these are part of the venting for the HVAC system. If I understand correctly this is an indication of a high efficiency heating system and one of the pipes is for air intake into the heating unit, one is exhaust (or is it condensation or is it both with a high efficiency unit), and I think, from what I’ve researched, is for condensation of the water heater. First is this correct if not what are they for? Second are they generally (or always) installed in a particular order (for instance is the top one always the air intake - or whatever)? and I have also noticed they all come out and point in different directions - is that specific (like if one of them is pointing a certain direction would that be an improper installation)? I also have noticed that often there is only 2 PVC pipes instead of 3; what is the difference? I also think these particular pipes in this picture seem to have a larger diameter than I usually see, is that something that is specific that could with certain specifications be observed as an improper installation.

Robert, can you post interior pictures of the pipes and where they come from and go to? :smile:

Larry, I’m not sure how much help there going to be but I will post what I have.
Here is the room where the heating unit and water heater are.
The far door is for close washer and dryer and the closer door (with the smoke detector above the door is where the HVAC & water heater are.

Here is the laundry area and to the right of that is the HVAC closet.

Here is the HVAC room.

Following are the best shots I have inside the HVAC closet.

Here you can see the cold air return between the furnace and the water heater.

Here is the top of the water heater.

and here is looking at the wall to the left of the furnace and a little bit of the top of the furnace.

Unfortunately I don’t have a good shot to the left of the top of the furnace (see the 3rd picture) but I think the pipes all went in to the wall behind this, as you can see by the second to last picture (above the water heater).
Are you thinking that it the order (to answer one of my questions) is not standard so you would need to be able to trace the pipes?
Sorry I don’t have better pictures. I thought possibly the pipes to the outside was all pretty standard no matter what the configuration in the house.

Sorry, Robert, with those pics, one would know better by being there.

The two different size filters are interesting, though.

Other than that, I don’t see anything awry.

Happy inspecting. :smile:

Robert, where exactly in the house was the furnace closet located? The reason for that question is the 2 louvered vents at floor level to the left and right of the door.

I would wager that one pipe is for intake air for the furnace and the other two are vent for the furnace and washer heater.

But like Larry said, can’t really tell without being there.

So I’m gathering by the responses that first of all it is not standard but more site specific, so you can’t by just looking at the pipes on the exterior identify that the top is always for X and the bottom is always for Y?
As to the location of the room it was a family room/living room on the back of the house which I was thinking might have been an addition as the roof to this area was added on from the roof of the rest of the house and was much flatter. I think those louvers that you inquired about were to heat this room.

I would guess that the bottom vent is air intake for the furnace and the other 2 above are for furnace and WH. A clearance is required between the gas meter to source of ignition thus the air intake located at bottom. Furnace / WH manufacturer have installation requirements which you may check. That dryer wall damper should not have a screen as it catches lint which may result in blockage/ fire.

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Thanks for everyone’s response. I appreciate everyone’s help.
I thought it was more cut and dry and more standardized, but I guess it is all site specific and by manufacturer’s installation requirements that may vary from manufacturer to manufacturer. So it sounds like the order is not standardized and neither is the direction they point either.

Each manufacturer has specific installation instructions that can be Google IF you get the make, model and serial numbers off the unit. It is a great help. :smile:

Good luck with your business

You have now been unfortunately been cursed.
Stay away Robert for your own good for proper education :cowboy_hat_face:


Yes Robert - this clown is your best mentor!

Look around here & see the debacle for yourself.


LOL very funny Marc :laughing:

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Up to 23. You go!

ZERO for you CHUMP


Mark you really need to get a life. Do you believe that any of your comments are going to change anything?

!00% off the voters are hoping it will change some things.



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Our members can obviously smell devious seft-aggrandized bullshit

STAY ON THE FORUM . . . . .0%