4" SV Conversion Kit ideal for indoor combustion air intake: for use on Condensing DV models only (Not for use in foam sealed attics, or where poor quality combustion air exists)

4" SV Conversion Kit for use on NORITZ condensing DV models tankless water heaters. Designed for atmospheric air intake when heater is installed in a space with sufficient combustion air available. Not for use in foam sealed attics, or where poor quality combustion air exists.