A:Answer The ENERGY STAR® Qualified LG 4.5 cu. ft. Ultra Large Capacity High Efficiency Front Load Washer with Steam Technology in Graphite Steel, Model # WM3770HWA, has 3/4" connectors on the hoses for the hot and cold water inlet valves that have to be connected a water supply. The water supply pressure must be between 20 psi and 120 psi {138-827 kPA}. A pressure reducing valve must be installed if the water supply pressure is more than 120 psi, so you will need to check on the specifications for your tankless water heater and check that it has the appropriate connections...^IFV