Here's a general procedure to flush a tankless water heater:
Turn off the power: Before you start flushing the water heater, make sure you turn off the power supply to the unit. This will prevent any accidents from happening during the flushing process.
Turn off the water supply: Next, turn off the water supply to the tankless water heater. This will prevent any new water from entering the unit during the flushing process.
Connect a hose to the drain valve: Locate the drain valve at the bottom of the tankless water heater and connect a hose to it. Make sure the other end of the hose is in a drain or outside where the water can flow out freely.
Open the hot water taps: Open all the hot water taps in your home to release any pressure in the tankless water heater and allow the water to flow out more easily.
Open the drain valve: Slowly open the drain valve and let the water flow out of the tankless water heater. Keep an eye on the water to make sure it's flowing smoothly and without any debris.
Flush the water heater: Once the water is flowing smoothly, you can begin flushing the tankless water heater. You can do this by letting water flow through the system for a few minutes, or until the water runs clear.
Close the drain valve: Once you've finished flushing the tankless water heater, close the drain valve and disconnect the hose.
Restore power and water: Finally, restore power to the tankless water heater and turn the water supply back on. Make sure you check the unit for any leaks and run hot water through all your taps to ensure the water is flowing properly.
It's recommended to flush your tankless water heater at least once a year to keep it running efficiently and to prolong its lifespan. However, it's always best to follow the manufacturer's instructions for your specific model to ensure you're properly maintaining your tankless water heater.