This can be done by shutting off the main gas or turning off the circuit breaker for electrical devices.

This procedure will prevent cold water from flowing into the water heater and prevent hot water from coming out during the cleaning process. The water valves consist of a cold water valve that may be colored blue, a hot water valve that may be colored red, and a third main valve that runs the water into your home.

The purge valves have small handles that resemble the letter “T. " This procedure is done to relieve any pressure that has built inside the valves and will prevent excess hot water from shooting out and coming into contact with your skin. There may be pressure when removing the purge port valve caps, so it is extremely important to make sure the hot water valve is completely and accurately shut off for safety purposes. Handle each cap carefully to make sure the rubber washer sealing discs stay in place, which are needed for your valves to function properly.

If the manufacturer of your tankless water heater did not provide you with hosing lines, you can purchase them from any retail store specializing in home repair or water heaters. The hosing lines must be long enough to reach between the water heater and your bucket. You may need to consult your manual provided by the tankless water heater’s manufacturer or contact the manufacturer directly for exact instructions regarding this procedure. In some cases, this procedure may require you to use a sump pump and connect hoses that will discharge and flush water from the tankless water heater using the cold and hot water valves.

Since your tankless water heater is most likely the source of all your drinking water and bathing water, using chemical cleaning solutions may be extremely harmful to your health.

This procedure may take up to 45 minutes.

Tighten the caps completely and firmly without breaking the rubber sealing discs located inside the caps.

This procedure may just require you to rotate and open the cold and hot water valves so they are parallel to the position of the main valve that leads into the house.

Continue to run the water until it runs steadily without air escaping. This procedure may take up to 2 or 3 minutes.