Rinnai Tankless Water Heater RUCS75i - sizing the gas pipeline

[MethodicalMind]

Inspector thinks flex appliance gas line being only a 1/2" line approx 30" in length may not be sufficiently allowing enough gas to flow for the amount of BTUs the tankless water heater can demand. House is a new build in 2022.


This specific tankless water heater can do 160,000 BTU/H Model: RUCS75i → REU-KCM2528FFU-US

 

[breplum]

Your plumber was surprisingly stupid, installing such a undersize flex line. Your inspector is correct. The flex line should be sized according to its own label listing capacity or A Plumbing codes have charts for the sizing as well.