Thread: Water heater venting

Does anyone have any info or sites on proper water heater venting sizes for flue piping? I had a rather large vent pipe on a water heater this week and it appears too large, but am not sure. Thanks for your comments in advance.

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Hi Jody,

The Whole Vent Needs Replaced.

No Draft Hood ( if it's there it is negated by being taped. )

No 1 foot vertical rise from the Gas Appliance before any turns.

Vent Connected with unlisted, unapproved material ( Duct Tape ) needs 3 screws per connection.

And I think The Correct Size of B Vent should be 4 inches.
*can't tell from the Photo but the other venting looks Questionable.
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Hello Jody,

From what I can tell from the picture there is a draft hood on top of the water heater, which is correct.

The flue pipe is a single wall vent maybe 5"? Increase of the vent pipe can be made and manufacturers recommend the increase be made at the draft hood. Usually the vent diameter is 3", but increase of vent diameter can be made due to the increases of the length of run before it terminates. The pipe connection look to be metal tape around the connection and screws maybe present under the tape, hard to tell from the pictures but you can run your hand around the connection and fell the screws. As Billy said you do need to have 3 screws per connection which may or may not be there, the tape would then be OK if there are screws holding the connection.

12" of pipe before an elbow is recommended by manufactures but not mandatory, this recommendation is for increase draw performance.

The one thing I see is the pipe connection to the draft hood, this pipe should be screwed to the draft hood. A proper vent increase connection should be installed.

Here is an link to State Industries on Install.
http://www.statewaterheaters.com/lit...186489-002.pdf

It also looks to me like the pipe may be down side up -- look at the indentatation under the tape at the first joint.

The best source of information on proper vent sizing is in the appliance installation manual or NFPA 54 (National Fuel Gas Code). Upsizing of the vent connector is generally permitted with the only absolute rule being the 7 Times rule which states no part of the venting system can be greater than 7 times the area of the appliance outlet (flue collar).

Jim Brewer

There are degrees of satisfaction in knowing the science and rules.

But I have to inform my clients that we are not AHJ’s.

In the above instance I would inform my client that “the 5” vent may be oversized and that this is the first instance I have ever seen it. Used to be 4” and about 20 years ago the custom was to use 3” vents.”

I would tell my client. “I’ll try to find an authoritative reference.”

I may also tell one of my clients privately about thanksgiving exposures to combusted methane gas.

I would compare the btu’s with the oven and 4 top burners venting into the living space to the water tank in a drafty basement.

Of course one can come up with some examples of exceptions to this logic, but I like to interject common sense as a foil to Draconian rules.

Originally Posted by Ken Bates

There are degrees of satisfaction in knowing the science and rules.

But I have to inform my clients that we are not AHJ’s.

In the above instance I would inform my client that “the 5” vent may be oversized and that this is the first instance I have ever seen it. Used to be 4” and about 20 years ago the custom was to use 3” vents.”

I would tell my client. “I’ll try to find an authoritative reference.”

I may also tell one of my clients privately about thanksgiving exposures to combusted methane gas.

I would compare the btu’s with the oven and 4 top burners venting into the living space to the water tank in a drafty basement.

Of course one can come up with some examples of exceptions to this logic, but I like to interject common sense as a foil to Draconian rules.

.
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Say What ?
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The Vent is Taped Together.

The Draft Hood is Taped to The Vent.

The Tape Will Catch Fire.

What Kind of Common Sense is it to tell Stories about Thanksgiving ?

* when your family is down at the Homeless Shelter You don't have to Clean Up Them Paper Plates Thanksgiving Dinner is Served On.
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[quote=Billy Stephens;126739].
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Say What ?

The Tape Will Catch Fire.


I have yet to see aluminum tape catch fire. I have seen the adhesive dry out and the tape fall off, but never have i seen it burn, even on oil fired boiler flues. I am not condoning it's use on vent pipes, but lets not blow it out of proportion.

Originally Posted by David Bell

Originally Posted by Billy Stephens

.
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Say What ?

The Tape Will Catch Fire.

I have yet to see aluminum tape catch fire. I have seen the adhesive dry out and the tape fall off, but never have i seen it burn, even on oil fired boiler flues. I am not condoning it's use on vent pipes, but lets not blow it out of proportion.

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David,

I've never seen Aluminum Tape Catch Fire as Well.
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* what I'm seeing from the posted picture is not made of aluminum.
.

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Thanks David Bell.

I also think the tape is Aluminum and based my response on that opinion.

It seems that Billy Stephens is absolutely certain that the tape is not Aluminum.

I have seen and used both types (cloth and Aluminum "Duct tape") and I feel that the tape is Aluminum.

Assuming cloth tape in the photo should we not see some degradation caused by heat over a short period of time. Cloth tape would show distress in a matter of a few days.

Also, the cloth could be obscuring the 3 required screws. People like Billy Stephens ASSume too much. (Some of them feeled threatened when reality
conflicts with their Stanford Binet scores)

Originally Posted by Ken Bates

Thanks David Bell.

I also think the tape is Aluminum and based my response on that opinion.

It seems that Billy Stephens is absolutely certain that the tape is not Aluminum.

I have seen and used both types (cloth and Aluminum "Duct tape") and I feel that the tape is Aluminum.

Assuming cloth tape in the photo should we not see some degradation caused by heat over a short period of time. Cloth tape would show distress in a matter of a few days.

Also, the cloth could be obscuring the 3 required screws. People like Billy Stephens ASSume too much. (Some of them feeled threatened when reality
conflicts with their Stanford Binet scores)

.
.Reality.
* my Mensa Score keeps me grounded there. ( and You? )

The Picture Does Speak for it's Self.
* as you were saying Ken.
.


.

The picture does speak for itself, check the lineset for the A/C with the duct tape falling off.

Well, anyways, can anybody say with certainty that this is a dangerous situation.

The photo shows lots of uncombustable space above. (air does not combust)

So Mr. inspector 'WHAT IS THE PROBLEM, WHAT IS THE DEAL BREAKER, TELL US WITH CERTAINTY WHAT BAD THINGS CAN HAPPEN WITH THIS SITUATION!

EASY TO BITCH FROM THE SIDE LINES WITH NO REPERCUSSIONS.

EASY TO BITCH WITHOUT DEMONSTRATING YOUR COMPETENCE IN SCIENTIFIC KNOWLEDGE. DO YOU HAVE A DIPLOMA FROM MIT OR CALTECH?