Takagi T-K2 tankless water heater is compatible with solar hot water systems, natural gas, and propane. Weighing in at 60lbs, this water heater measures 25" x 16.5" x 8.3" and starts with an electronic ignition and an AC 120 V power supply. Featuring 3/4" NPT water and gas connections, water pressure from 15 to 150 psi, this water heater requires a natural gas input of 20,000 BTU to a maximum of 185,000 BTU or for LPG input a minimum of 19,000 BTU to a maximum of 175,000 BTU. Natural gas pressure inlet minimum of 5" WC and maximum of 11" WC. LP gas pressure inlet minimum of 11" WC and maximum of 14" WC. Mainfold pressure for natural gas is 2.3" WC, and for propane 2.5" WC. HOT WATER ON DEMAND AND ENERGY EFFECIENCY IN A SUPERIOR MODEL!