Tankless Venting

[Joe Reilly]

Doing the report now, so any quick responses would be grateful.

Question regarding a tankless water heater, do both vents need to terminate outside. This was mounted in the garage and I can only assume this is intake, and there is a single out take.

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[Dom D'Agostino]

Noritz lists all the vent requirements for the specific models in the install guide.

Interior installation of the direct vent unit when supplying combustion air from indoors is listed/allowed under certain conditions, on water heaters labeled "SV convertible", with the appropriate adaptors.

Here is an example of the specs:
https://www.noritz.com/wp-content/up...B-rev.0117.pdf

And an adaptor:
Conversion kit

[Joe Reilly]

Noritz lists all the vent requirements for the specific models in the install guide.

Interior installation of the direct vent unit when supplying combustion air from indoors is listed/allowed under certain conditions, on water heaters labeled "SV convertible", with the appropriate adaptors.

Here is an example of the specs:
https://www.noritz.com/wp-content/up...B-rev.0117.pdf

And an adaptor:
Conversion kit

Thank you, however I do not agree with it to allow combustion air from a garage, with the possibility of fumes around the area.

[Jerry Peck]

Interior installation of the direct vent unit when supplying combustion air from indoors is listed/allowed under certain conditions, on water heaters labeled "SV convertible", with the appropriate adaptors.

See note at top of page 22, then read what is shown on page 22 when using combustion air from indoors (see table, 3rd column from left, for indoor makeup air) ... note that it states "free area" of each opening - the code states reductions for metal louvers and for wood louvers which take into consideration the metal or wood louvers (slats) reducing the measured opening size of the opening to a "net free vent area" size of the opening (think of it as sliding all the louvers down to the bottom or to one side, the size of the opening which would be left is the "net free vent area", or, in this case, the "free area" required).

[Dom D'Agostino]

Thank you, however I do not agree with it to allow combustion air from a garage, with the possibility of fumes around the area.

Water heaters have been using garage combustion air for many decades; they require properly configured supply to allow adequate air flow, and several other considerations for a safe and compliant installation.

Otherwise, just install a direct vent model (and install it as a DV unit).

[Jerry Peck]

Thank you, however I do not agree with it to allow combustion air from a garage, with the possibility of fumes around the area.

Are you concerned when you see other gas heaters (furnaces and water heaters) in the garage drawing combustion air from the garage? Same concerns (or lack thereof) would be applicable to these types of gas heaters too.