To install a tankless gas water heater, you need to follow these steps:
1. Obtain the necessary permits or clearances from your local authority.
2. Shut off the water and gas supply to your old water heater and remove it.
3. Mount the new tankless water heater on the wall and install the gas line.
4. Install new water lines and a pressure relief valve.
5. Install the exhaust vent, if needed, according to the manufacturer's instructions.
6. Turn on the water and gas supply and test the water heater for leaks and proper operation.
