Water heaters
No hot water? What to check first
Updated
Short answer
On a gas water heater, check that the pilot is lit and the gas valve is on. On an electric heater, check the breaker and the high-limit reset button. If the pilot won't stay lit, the breaker trips again, or you smell gas, stop and call a plumber.
Gas water heaters
Many newer gas heaters have a sealed burner with an indicator light rather than a visible flame. The label on the tank explains how to check and relight.
- Is the gas control knob on 'on' rather than 'pilot' or 'vacation'?
- Is the pilot lit, or is the status light blinking a code?
- Are other gas appliances working?
- Has the flame-sensor safety tripped from a blocked air intake?
Electric water heaters
- Check the breaker; reset it once if tripped
- Press the red high-limit reset under the upper access panel, with power off
- If the breaker trips again, an element may have shorted
When to stop
If you smell gas, leave and call the gas utility. If water is leaking from the tank or the relief valve is spraying, shut off the cold water inlet and the fuel or power, then call.
What the plumber checks
On a gas heater, the plumber tests the thermocouple or flame sensor, the igniter, the gas control valve and the venting, including the draft. On an electric heater, they test each element and thermostat with a meter.
They'll also read the age from the serial number and check for leaks, so you can decide whether a repair is worth it.
- Pilot, igniter and flame sensor
- Gas valve and venting
- Elements and thermostats
- Tank age and condition
When to call a plumber
Call if the problem keeps coming back, if water is reaching walls, ceilings or electrical areas, or if any step above involves gas, a torch or opening a sewer line. A licensed plumber handles water heater repair and will explain the cause before starting.
Questions
Why does my hot water run out so fast?
Is it safe to relight a pilot myself?
This guide is general information for Colorado homeowners, not a substitute for an on-site diagnosis. Local codes vary; your plumber and building department have the final word.