Gas Appliances Venting

[William Kievit]

Came across this vent yesterday. I expect to see the water heater connected above the furnace. I also am not sure of the elbow connection at the base of the stack.
I would like your thoughts.
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By the way, I found the gas fired units in the closet at the back of the garage. Outside air vented in through the back wall (vent too small). This was in a 100 unit condo development built in 1988.
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[Mark Reinmiller]

Came across this vent yesterday. I expect to see the water heater connected above the furnace. I also am not sure of the elbow connection at the base of the stack.
I would like your thoughts.
30273

By the way, I found the gas fired units in the closet at the back of the garage. Outside air vented in through the back wall (vent too small). This was in a 100 unit condo development built in 1988.
30274

I hate to see any appliance entering into the bottom of a B-vent. I see too many cases where condensation runs back the flue connector.

It looks like the closet is part of the garage and not the house. Even if the door meets fire-resistance requirements, without a door sweep or step then the appliances should be raised to meet the 18 inch requirement concerning height to an ignition source.

[Raymond Wand]

There also is not positive slope on the vent from hot water heater.

[Bill Penn]

I would also suggest that the smaller flue enter above the larger flue.

[Fred Herndon]

William,
The appliance with the highest BTU output should always start the vent, and the smaller should enter above it to help prevent condensation, as someone else said (for some reason this thing won't let me scroll down to read previous posts). Also the horizontal arm looks to be, well, horizontal. Should have enough rise to prevent back drafting CO into the room.

[Scott Cook]

If anyone knows of any code that prohibits the entrance of the water heater vent into the bottom of the tee instead of the side, I would like to see it. Okay, I was wrong. IFGC 504.10.4

The 3" horizontal connector cannot be more than 4.5' long. If it is a 4" horizontal connector then 6'.
All single wall pipe must have 3 screws 120 degrees apart fastening the joints.
The draft hood legs must be screwed to the heater, unless they are the "twist & lock" type.
Some water heater manufacturers require a minimum vertical rise before the first elbow, such as six or 12 inches, above the draft hood, but you would have a hard time finding the original IOM for something that old.

[Bob Burke]

I can't tell from the picture, but is there even a upwards slope on the water heater flue? The door to the furnace room should also be self closing.

[Scott Patterson]

For what it's worth, I don't thing that draft hood goes to that water heater.

[Jim B Robinson]

If anyone knows of any code that prohibits the entrance of the water heater vent into the bottom of the tee instead of the side, I would like to see it. I would not write it up, as it is perfectly legal.

For Canadian installations - B149 Natural Gas & Propane Installation Code
A Type B vent is listed equipment -must be installed as per its listing.
It's a "vent connector" from the water heater to the Tee.

[Mark Reinmiller]

If anyone knows of any code that prohibits the entrance of the water heater vent into the bottom of the tee instead of the side, I would like to see it. I would not write it up, as it is perfectly legal.

The 3" horizontal connector cannot be more than 4.5' long. If it is a 4" horizontal connector then 6'.
All single wall pipe must have 3 screws 120 degrees apart fastening the joints.
The draft hood legs must be screwed to the heater, unless they are the "twist & lock" type.
Some water heater manufacturers require a minimum vertical rise before the first elbow, such as six or 12 inches, above the draft hood, but you would have a hard time finding the original IOM for something that old.

I did not say that the flue entering the bottom of the B-vent was against code. But I have seen many times where this has resulted in corrosion and leakage from the flue connector, and has even run back into furnaces (when they enter at the bottom, which is more common) and caused corrosion.

Regarding the horizontal distances you mention, where are those numbers from? As I recall from the IRC or National Gas Code, I believe the horizontal distance is a function of the B-vent height and would typically be significantly greater than those numbers.

[Rod Butler]

I would also suggest that the smaller flue enter above the larger flue.

Not just a suggestion, it is required.

[Darren Miller]

The door to the furnace room should also be self closing.

Why?

The entire furnace should be raised so the source of ignition is 18 inches above the garage floor.

[Matt Fellman]

You're all wrong :)

This thread is a perfect example of why HIs should not design fixes and tell people specifically what to do. Code? Suggestion? Manufacturer's Spec? Incorrect Information? Regional Difference? Yep, you can find all 5 here. Pretty much everyone on this thread has a different opinion.

I have no problem with all these things being tossed around an internet forum thread but I personally stop short of making any specific recommendation.

My write-up would probably go something like this:

Numerous unorthodox and potentially incorrect/unsafe conditions were noted throughout the installation and venting of the gas appliances in the garage. Properly venting gas appliances is a critical part of installation and when done incorrectly a substantial safety hazard can result. Further review by a qualified HVAC contractor is recommended to evaluate and make any necessary changes.

[Jack Feldmann]

For what its worth, the heater is probably fine since the burners are likely over 18" from the floor.

[Jerry Peck]

For what its worth, the heater is probably fine since the burners are likely over 18" from the floor.

Jack,

Isn't it likely that there is a blower and/or controls and switching down behind the lower front access panel?

Any of those items would be ignition sources.

[Matt Fellman]

The problem I see with that write up is that if the original installer is the HVAC contractor that is called to review the installation ,he will say that it is OK and that the HI does not know what he is talking about.
This type of write-up usually indicates that the HI does not know what he is talking about.
I think that you need to put some meat on the bones in order to specify what the issues are.

Yeah, I see your point. I'll often include something like:

The following items should be specifically evaluated along with any other findings the HVAC contractor has:

comment - picture
comment - picture


Or:

The following are examples of the conditions found:

comment - picture
comment - picture

I personally just never want to lead people to believe I'm the end all authority on anything...... that was my main point. Once you tell them exactly how to correct something all it takes is someone to disagree with you and it all blows up in your face. At best it's a slough of phone calls.... at worst you're talking to your E/O carrier. Not because you did anything wrong and you may well be right. Right doesn't always win in this ass backwards world we live in. It's just a numbers game. 350 inspections a year and you're going to run into some nuts.