A little, often
Most tankless upkeep is quick: a glance at the display, a look at the vent outside, a check for drips under the valves. The bigger task, flushing the heat exchanger, comes around at the interval your manual sets. In Fullerton's hard water, that interval matters more than in softer-water areas.
Use the calendar as a starting point. Pick months that suit your household, write them on your home calendar, and record what you find in the flushing log.
Suggested calendar
- January
- Look at the outside vent termination for blockage, nests or debris. Test carbon monoxide alarms.
- February
- Check under the unit and at the service valves for drips or mineral crust.
- March
- Clean shower heads and faucet aerators; hard-water buildup can lower flow below the unit's minimum.
- April
- Clean the inlet filter if the manual calls for it, and note what you find.
- May
- Walk the path to the main water shutoff and gas meter; make sure both are reachable.
- June
- Flush and descale, or schedule a plumber, if this matches your interval.
- July
- Glance at the display for any stored codes and update the error log.
- August
- Check that the condensate line, if any, drains freely.
- September
- Clean the inlet filter again if your log shows debris builds quickly.
- October
- Inspect the vent again before the cooler months when the unit works hardest.
- November
- Confirm the temperature setting is safe and comfortable for the household.
- December
- Review the year's logs and decide whether the flushing interval needs adjusting.
Tools to keep near the heater
- The owner's manual or a saved copy on your phone
- A flashlight
- A towel and small bucket for filter cleaning
- The flushing log and error log
- The shutoff map
Ask at your next service visit
- Should any calendar items be more or less frequent for this model?
- Is there anything in the logs that worries you?
- Does the vent termination still meet the manual's clearances?
Common questions
Do I have to flush in June?
No. Flush when your manufacturer's interval and your log say it is due; June is just an example.
Why test carbon monoxide alarms on this calendar?
A gas tankless unit burns fuel and vents exhaust, so working alarms are an important safety backup.
Is an outdoor unit's calendar different?
Add checks for weather exposure and the cover, and follow the manual's guidance for outdoor models.
General information for Fullerton, not a quote or professional advice. In an emergency, call 911.