Noritz NH150-DVLP Direct Ventilation Hydronic Boiler Propane White Fully modulating burner - Automatically adjusts burner level accordingly Dual temperature controls - for indirect domestic water heating (temp. priority 1) and hydronic heating (temp. priority 2) Thermal Efficiency: 82.8 percent (LP) Dual flame burner - Noritz exclusive! Minimizes temperature fluctuations ASME certified