Tank water heater annual service: T&P test, flush, anode check, temperature and venting look
A.O. Smith and Rheem both call for testing the temperature-and-pressure relief valve at least once a year and flushing sediment at least yearly (every six months in hard water, and A.O. Smith's manual says every six months). Anode intervals vary by maker and water: check it annually to every few years and replace it when several inches of core wire show. Set the thermostat around 120 F. On gas units, look at the vent and burner area but leave any gas-side work to a licensed tech.
Before you start
- T&P discharge is tank-temperature water and will scald; aim it into a bucket through the discharge pipe and keep hands clear
- Electric units: turn the breaker off before draining so the elements are not energized dry
- Gas units: set the control to pilot or vacation per its label; do not touch gas piping, the gas valve body or burner adjustments
- Never plug or cap the T&P discharge line
Diagnostic steps
Unlock all 7 steps with expected values
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