To keep your tankless water heater in prime condition, it is advised to clean out the filter once every six months. This routine maintenance is easy to do and only takes a few minutes. Simply watch our how-to video above or continue reading to learn how to clean your tankless water heater filter.


  1. Step One: Turn Off the Power to Your Tankless Heater

    Before you get started, you will need to turn off the power to the unit. The switch is typically located slightly below and to the right of the water heater.

    Shutting off the power to the tankless water heater.


  2. Step Two: Remove Lower Panel and Shut Off Cold Water Going In

    Remove the fastener screw from the lower panel, and then remove the panel. You do not go into the upper panel, which should only be accessed by a trained professional. There will be two valves. First, shut off the cold water coming in by lifting up the handle.

    Removing the access panel on the tankless water heater.


  3. Step Three: Close The Hot Water Valve And Flush Out Any Water Remaining in the System

    Your flush valves may look a little different than pictured depending on the model of your tankless water heater. The next valve to shut off is for the hot water coming out of the unit. After lifting this valve to shut it off, there will still be some water trapped inside of the system. Find the valve connected to the drainpipe. This is the pressure release line. Release this valve, and a small amount of water should come out.

    Shutting off the hot water valve.


  4. Step Four: Remove The Filter

    If your tankless water heater is a Noritz brand, the filter will be side-mounted in between the flush valves. If you are the owner of an older Granville home, you may instead have a Rinnai brand tankless water heater, and the filter will be located at the center of the unit. Once you have located the filter, unscrew the filter plug, remove the plug and the filter, and then remove the filter by sliding it off the plug.

    Removing the filter.


  5. Step Five: Remove Debris From The Filter

    Using a rag, small brush, or a crevice tool, clean out any debris that’s inside the filter. Rinsing the filter with water can also help remove debris.

    Cleaning out the small filter.


  6. Step Six: Reinstall The Filter

    Once that’s all clean, re-attach it to the plug, and reinstall the plug and the filter. Do not overtighten when reinstalling the plug, you want this to be hand tight only.

    Reinstalling the filter.


  7. Step Seven: Turn it All Back On

    Once the filter plug is back in place, close the pressure relief line that you opened earlier to release the remaining water in the system. Next, open up your hot water line, followed by the cold water line. Close the panel back up and turn the power back on, and you’re good to go. Perform this maintenance every six months as needed.

    Putting the panel back onto the tankless filter.


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