Water heater error codes (tank & tankless)

Last updated: October 5, 2026

Pick your brand to see the water heater error codes we cover. Each code page explains what the code means, the likely causes, the safe steps to try (easiest first) and when to call a pro.

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Before you look up a code

Most water heater codes come down to ignition or flame sensing, venting and combustion air, water flow or scale build-up. Gas and venting faults are safety issues — if you smell gas, leave and call your gas company, and leave gas lines and burners to a licensed pro. Write down the exact code and your model number first — codes can differ between model families of the same brand.

Looking for something else? See washers error codes, dryers error codes, dishwashers error codes, refrigerators error codes, ovens & ranges error codes, microwaves error codes, air conditioners & heat pumps error codes.