Water Heater Diagnostics Flowchart

Purpose

Systematic diagnostic flowchart for tank-style water heater issues.

No hot water, insufficient hot water, strange noises, leaking, or discolored water from a tank water heater

Check pilot light (gas) or breaker (electric)

Gas: check thermocouple, gas valve, pilot assembly

Electric: check upper/lower heating elements and thermostats with multimeter

Check reset button on upper thermostat

Verify gas supply is on and unobstructed

Check thermostat setting — should be 120°F for residential

Check dip tube — broken dip tube mixes cold into hot output

Gas: check burner flame pattern — yellow/uneven means service needed

Electric: test both elements — failed lower element is most common cause

Check tank size vs. household demand — may need upgrade

Sediment buildup is most common cause — recommend flush

Perform bucket blast to show customer sediment condition — photo results

Whining may indicate failing element (electric) or scale buildup

Identify source: T&P valve, drain valve, fittings, or tank itself

T&P dripping: check water pressure (under 80 PSI?) and temperature setting

Fitting leaks: tighten or replace. Check flex connectors for corrosion

Tank leak (bottom/side): tank has failed — replacement required

Check for condensation vs. actual leak on newer units

Rust-colored: corroded anode rod or tank deterioration

Check anode rod condition — recommend replacement if depleted

Sulfur smell: bacterial growth — flush and consider powered anode rod

Water pressure check (static) — 40-80 PSI range

CO test at draft hood and flue connections

Bucket blast — show customer tank bottom condition

Check expansion tank pre-charge with tire gauge

Visual inspection of flue, venting, connections

Check for backdrafting