Thread: Vent near window

I wrote this in the report, vent too close to window. Pretty simple, right? Well the HVAC contractor called me and said the vent can be located 3 feet from the window if the furnace is 100,000 btu's or less. I have not heard of this. Plus is was 33 inches, that pissed him off. Have you heard of this rule. I simply refered to 1804.2.6 IRC

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Originally Posted by mathew stouffer

I wrote this in the report, vent too close to window. Pretty simple, right? Well the HVAC contractor called me and said the vent can be located 3 feet from the window if the furnace is 100,000 btu's or less. I have not heard of this. Plus is was 33 inches, that pissed him off. Have you heard of this rule. I simply refered to 1804.2.6 IRC

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Matthew,

I think the HVAC Guy is Correct.
If it's a Direct Vent.

* attachment is from Rudd installation instructions and shows as close as 12 inches.
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Matthew,

Hopefully someone with more heater knowledge will chime in soon, but I will give it my best shot.

According to my Code Check, vent termination is a minimum of 4 feet below, 4 feet horizontal or 1 foot above building openings. IRC 2427.8 or UMC 802.8.2

However, heating is not my long suit and I could very well be wrong. Maybe we will hear from Bob, JP, Jerry Mc or one of the other heating guys.

The document that Billy posted had this:

A vent termination shall not terminate over public walkways
or over an area where condensate or vapor could create
a nuisance or hazard or could be detrimental to the
operation of regulators, relief valves, or other equipment.

While a deck is not a walkway, the condensate might "create a nuisance or hazard".

Gunnar, that's what I thought.

Originally Posted by mathew stouffer;109405

Gunnar, that's what I thought.

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Which One ?

The 4 Feet has to be a NON Direct Vent Appliance.
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12" clearance to a window for a direct vent appliance less than 100,000 btu is correct.

However, it should also be at least 12" above the deck. Possibly more if you get snow where you're at.

Originally Posted by Ken Rowe

12" clearance to a window for a direct vent appliance less than 100 btu is correct.

However, it should also be at least 12" above the deck. Possibly more if you get snow where you're at.

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Bingo !

We Have a Winner !
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Originally Posted by Billy Stephens

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Bingo !

We Have a Winner !
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I won! I won! When do I get my check?

Just to clearify, it's late. So the direct vent can not be located within 12 inches if it >100,000 btu?

Originally Posted by mathew stouffer

Just to clearify, it's late. So the direct vent can not be located within 12 inches if it >100,000 btu?

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Just the opposite.
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Originally Posted by Ken Rowe

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II won! I won! When do I get my check?

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.....
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..
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Originally Posted by Billy Stephens

The 4 Feet has to be a NON Direct Vent Appliance.

Billy,

I guess I don't understand what a direct vent appliance is. Can you describe it in words of 2 syllables or less?

Originally Posted by Gunnar Alquist

Billy,

I guess I don't understand what a direct vent appliance is. Can you describe it in words of 2 syllables or less?

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Cat 1.
* fan assist com bus tion.
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A Little better Clearance Reference Chart.
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The pipe is plastic indicating that it's a hi-efficiency condensing furnace or a high-efficiency boiler. Those are considered direct venting and don't apply to the 4' rule. If the pipe were stainless steel or a power vent box, then it would be too close.

Is it direct or power vent?

Per the IRC definitions, a "direct vent" simply means it takes all the combustion air from outdoors and exhaust all the flue gases to the outdoors. If this indeed has an 'inny' and an 'outey' it is direct vented. If it is greater than 50,000 BTU/hr input, you would need a 12" clearance to any air opening to the building and above the deck. The air intake for the DV does not count.

The previously noted remarks about condensation, snow, etc. ALL could apply here. Btw that corner, the trellis/ pergola/ awning, etc. and the building, this setup would be prone to making an ice rink in winter and rotting boards. If this is in the snow belt, it could be a HUGE issue. That is precisely why Mass now requires exhaust terminations min. 4' above grade/ surface.

The mfrs. listed instructions may require a more stringent clearance so that should ALWAYS be referenced in any inspection. You don't necessarily have to look it up---just say *someone* should look it up to be sure.

While we're at it, that DV termination in the decking looks to be a problem. You definitely need to look that one up in the listed instructions. As for the PDF supplied, my question is, is this chart from THIS appliance or just some chart from some other appliance? You cannot indiscriminantly cross-pollenate with specs.

Keep in mind you have the applicable codes including local ordinances, the mfrs. listed instructions, then just plain common sense issues you can call out. If this installation would be predisposed to condensation related issues, you can call that out regardless of codes and stds.

HTH,
Bob

Originally Posted by Ken Rowe

I won! I won! When do I get my check?

You did not win----you said "100" btus. You meant 100,000 but actually the 2009 IRC G2427.8.3 (503.8) now states greater than 50,000 BTU/hr.

Still, it was a nice try :-)
Bob

Ok. I am putting the vent is too close to the window. And yes Bob, the deck is a piece of crap

Bob is correct, and the 50KBtu/h is also defined in the Fuel Gas Code that most manufacturers base thier installation manuals upon.

Remember, as Bob stated, direct vent means that the intake air is taken from outside the structure, and combustion gas is deposited outside the structure. This mainly applies to the installation of Cat 4 appliances, as most Cat 1 appliances (most non-condensing furnaces for sake of clarity) pull combustion air from inside the structure.
Just because the appliance is defined as a Cat 4 appliance does not mean it is direct vent. Many Cat4 appliances still allow combustion air to be taken from inside the structure. This type of vent configuration would not be a direct vent application, and are refered to as an "Other than direct vent" application.
In this type of "Other than direct vent" application, the clearance from the bottom and side of an operable window would be 4 feet, with a minimum 1 foot clearance to the top. This is because when combustion air is taken from inside the structure, the interior of the house is more easily subject to negative pressures, more readily pulling flue gasses into the subject window.

Looking at the pictures, I keep finding more things to question.

What is the other intake/exhaust to the left of the vent? If its an exhaust, it's too close to the furnace intake pipe. If it's an intake, it's too close to the furnace exhaust.
What is the distance from the bottom of the intake to the bottom of the exhaust? Most manufacturers require at least 12 or more inches of seperation.
What is the distance to the inside corner? Many manufacturers require 3 feet, but with the spa creating an alcove type area, swirling winds and recirculation of flue gasses becomes a very likely issue.

I see the deck as a double edged sword.
Although it will help to separate the intake and exhaust air, it WILL become a hazard in the winter when the exhaust gas causes freezing condensate on the walk surface.
Also, do you really want someone enjoying the spa while breathing the exhaust gasses from the furnace? Not a good idea if you like your health.

Originally Posted by Bob Harper

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As for the PDF supplied, my question is, is this chart from THIS appliance

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Generic ( I have No way of knowing who made this Appliance. )

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You cannot indiscriminantly cross-pollenate with specs.

HTH,
Bob

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Correct,
Model Specific is Always The Way to Go.
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Ok let me just post some pics and it will answere any questions you may have. Pic one says it all, it was a little DIY nightmare back there.

Gee, is that beam supporting those jacks pressure treated???? :-)

Was this done by a Jack Leg who doesn't know Jack Squat?

They've also got the jacks under the wrong board, all they are doing is pushing against nails holding that board to the other board.

Mat,

You've also got a problem with those electrical PVC conduits coming from that disconnect being that close to that high heat source, as well as the other PVC.

Looks like the location of that direct vent termination may be suspect in every other way.

The entire thing was all jacked up