tankless water heater vent

mathew stouffer · 09-02-2009, 06:49 AM

These are the intake and exhaust vents for a tankless water heater. Besides the obvious, can the exhaust vent be that close to the combustion air vent. Furthermore, the exhaust vent located in the utility room is contacting a joist. I could not read the clearance requirements on the vent. Anyone know.

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A.D. Miller · 09-02-2009, 07:16 AM

Originally Posted by mathew stouffer

These are the intake and exhaust vents for a tankless water heater. Besides the obvious, can the exhaust vent be that close to the combustion air vent. Furthermore, the exhaust vent located in the utility room is contacting a joist. I could not read the clearance requirements on the vent. Anyone know.

MS: It is too close to the intake and too close to the A/C condensor

mathew stouffer · 09-02-2009, 07:50 AM

Good point. What about combustible clearance?

**Michael Thomas** · 09-02-2009, 08:15 AM

Mathew,

Looks wrong to me, too, however check the manufacture's installation instructions - I've been burned before by closer clearances and/or "stranger" intake/exhaust than I would have supposed to be acceptable based on more general requirements.

Darin Redding · 09-02-2009, 09:19 AM

As I understand it, the exhaust vent must be 1/2" from any combustible materials.

Dennis Krouse · 09-02-2009, 09:35 AM

1 inch from combustibles.

**Jerry Peck** · 09-02-2009, 09:45 AM

Originally Posted by Dennis Krouse

1 inch from combustibles.

That is for Type B gas vents, but not for direct vent vents, right? I believe the vents for direct vents are different.

mathew stouffer · 09-02-2009, 10:20 AM

The vent was very flimsy, like single wall vent. But It may be double lined.

Dennis Krouse · 09-02-2009, 10:50 AM

The install pictured is bringing combustion air in one pipe and exhausting out the other. In those types of vent it is 1 inch clearance for the exhaust vent. Where the intake and exhaust are combined in a concentric vent it may be reduced to zero.

**Jerry Peck** · 09-02-2009, 11:56 AM

Originally Posted by Dennis Krouse

The install pictured is bringing combustion air in one pipe and exhausting out the other.

Dennis,

The clearance to combustibles is, I think, being asked about the second photo, which shows a different vent than in the first photo.

Dennis Krouse · 09-02-2009, 12:14 PM

He will need to tell us if its concentric vent or just exhaust vent and who made it if possible. Looks too small to be concentric. But pics can be deceiving. In that first pic I'm trying to figure out whats what.

**Michael Thomas** · 09-02-2009, 12:16 PM

Uh... forget the clearance, they are going to have to reroute that entire vent...

And I think that's single-wall stainless in any case - which has a whole different set of clearance requirements,for a high BTU appliance that can be as much as 12" vertically if its "enclosed", as for example in a chase.

mathew stouffer · 09-02-2009, 01:57 PM

There is an intake and exhuast in the second photo, you just can't see the one vent, but there are two there. Like Dennis said, one is an intake the other an exhaust. I could not read the label, but it felt like single was vent. The how thing seem like a hack job.

mathew stouffer · 09-02-2009, 01:58 PM

Like my spelling, a hack job

Dennis Krouse · 09-02-2009, 02:23 PM

Metal Fab and Z-vent , both popular single wall stainless steel vent for cat 3 tankless w/h. , require 1 inch from combustibles. Of course the appliance mfg. may increase this distance but Noritz, Takagi and Rinnai all have a one inch clearance on the exhaust vent in this type of installation.

**Ron Hasil** · 09-02-2009, 03:18 PM

Noritz N vent in an enclosure like the chase pictured on a horizontal run there must be 10" clearance on each side 15" from the top and 6 " on the bottom.

Protech FasNSeal Enclosed is *' from the sides 12" from the top and 4" from the bottom for a horizontal run.

Manufacturer and_____________ Enclosed _________Unenclosed
Product ____________________Hor. Vert. __________Hor. Vert.
Noritz N-Vent ____________________4"____________ 1"__ 1"
Protech FasNSeal _________________4" ____________3"__ 3"
Protech FasNSeal W2 ___________6"_ 4"____________ 3"__ 3"
HeatFab SafTVent ______________6" _6"____________ 2"__ 2"
Z-Flex Z-Vent _________________8"_ 4"____________ 1"__ 1"
Flex-L-StaR-34 ________________8"_ 4" ____________1"__ 1"

mathew stouffer · 09-02-2009, 06:40 PM

I think it was a Noritz.

**Ron Hasil** · 09-03-2009, 04:58 AM

Originally Posted by mathew stouffer

I think it was a Noritz.

The vent piping is hard to tell what brand it is, but it dosnt look like the Noritz N-Vent. Noritz N-vent has quick lock connectors on all its joints. Have a look at the piping on their web page here. Vent Pipes for Noritz Tankless Hot Water Heaters

Here is Noritz PDF page 41 on clearance requirements from vent terminations to building openings. http://www.inspectionnews.net/home_i...1&d=1251978783