Tankless Water-Heater Maintenance
A little cleaning can help tankless water heaters perform like new
To function efficiently, a tankless water heater requires periodic maintenance. Here are three easy-to-accomplish tasks.
Clean the air filter
Turn off and unplug the unit, then remove the front cover. Locate the air filter and remove it. A dirty filter can reduce performance, so give it a good look. If necessary, clean it using a soft-bristled brush and a mild solution of dish soap and water. Rinse it with clean water, dry with a lint-free towel, and reinstall.
Clean the in-line water filter
Locate the in-line water filter at the cold-water inlet. A clogged water filter also can diminish the heater’s performance. Before removing the filter, close the cold-water supply valve to turn off the water supply to the unit. Clean the filter by tapping it, running it under water, or wiping it with a cotton swab. Reinstall the filter, and reopen the cold-water supply valve.
Flush the unit
Mineral deposits from hard water also can reduce a tankless water heater’s performance. Clearing out these deposits is a little more involved.
- Begin by unplugging the water heater and closing the shutoff valves on both the hot- and cold-water lines.
- Connect a hose from the outlet of a circulation pump to the cold-water service valve, and connect a drain hose to the hot-water service valve.
- Pour 4 gal. of undiluted food-grade white vinegar into a clean 5-gal. bucket, and place both the drain hose from the hot-water service valve and the pump supply hose (connected to the pump’s inlet) into the vinegar.
- Open the service valves on both the hot- and cold-water lines.
- Turn on the pump, and allow the vinegar to circulate through the system at a rate of 4 gal. per minute.
- After at least an hour, flush the system with cold water to remove the vinegar and any loose minerals.
- Remove the free end of the drain hose from the bucket, and run it either to a drain or outside.
- Close the cold-water service valve, open the cold-water supply valve, and allow water to flow through the heater for five minutes.
- Afterward, close the cold-water supply valve, and clean the in-line water filter at the cold-water inlet on the heater to remove any loose deposits the filter picked up during the process.
- Clean the filter by tapping, running under water, or wiping with a cotton swab.
- Once clean, replace the filter.
- Close the hot-water service valve, and open both the cold- and hot-water supply valves.
- Disconnect all of the hoses, plug the unit back in, and power it on.
Before doing these or any maintenance protocols, check your make and model for specific requirements.