Tankless Unit Gas Connector

[inspectorwill]

Anyone know if flexible gas connectors are required on tankless units. The Rinnai manual does not specify. Simply states 3/4" gas pipe required. Unit is currently piped with rigid 3/4" supply. Thanks

[rossneag]

Will,

Unless your local code prohibits flex connectors I would see no problem IF the proper length and BTU output of the connector met or exceeded the demands of the hot water heater and complied with the tankless manufacturer install docs. Remember, these things consume A LOT OF GAS (100,00 to 250,00 BTUs/hr) under full demand and you must account for this.

FWIW, rigid pipe is always better in my mind.

[resqman]

Since a tankless does not store water, when the ground starts a shakin' there is relatively little water weight to worry about. The flex line could be useful on the West coast but you would need to check you install instructions for the particular unit.