Problem Overview
When your home loses hot water, the issue often stems from a water heater that has shut down unexpectedly. For gas models, this usually means the pilot light has gone out due to a draft, a gas supply flicker, or a dirty sensor. For electric units, a tripped breaker or a high-limit safety switch is the likely culprit.
Knowing how to restart a water heater allows you to restore comfort to your household without waiting hours for a service call.
Tools Needed
- A long-reach lighter or fireplace matches (for older gas models)
- A bright flashlight
- An insulated screwdriver (for electric access panels)
- Heavy-duty work gloves
Step-By-Step Instructions
Step 1: Determine if your unit is gas or electric. For gas heaters, look for a control dial with “Pilot” and “On” settings. For electric units, check your home’s main electrical panel for a tripped double-pole breaker. If the breaker is centered, flip it to “Off” and then back to “On” to restore power.
Step 2: If you have a gas heater, rotate the control knob to the “Off” position. Wait at least five to ten minutes for any lingering gas to clear out of the combustion chamber. This waiting period is a vital safety measure to prevent a flare-up when you attempt to reignite the flame.
Step 3: Remove the access panel at the bottom of the tank. Use your flashlight to locate the pilot burner. If your heater has a piezo igniter (a red or black button), turn the knob to “Pilot,” press it down firmly, and click the igniter button repeatedly until a small blue flame appears.
Step 4: For older gas units without a built-in igniter, hold the control knob down in the “Pilot” position while carefully placing a long lighter flame against the pilot burner. Once the flame catches, continue holding the knob down for sixty seconds to allow the thermocouple to heat up and hold the valve open.
Step 5: Release the knob slowly. If the flame remains on, turn the dial “On”. You should hear the main burner ignite. For electric models, if the breaker was fine, remove the upper access panel on the heater and press the red “Reset” button located on the high-limit thermostat.
Step 6: Replace all access covers and panels. Listen for the sound of the unit heating, which may include a low hum or a steady flame sound. Check a hot water faucet in about thirty minutes to verify that the temperature is rising as expected.
Safety Warnings
Gas water heaters require extreme caution; if you smell a scent like rotten eggs, leave the house immediately and do not touch any light switches or electronics. Never attempt to restart an electric heater if you see standing water around the base, as this creates a significant shock hazard. Do not bypass any safety sensors or thermostats in an attempt to force the unit to run, as this can lead to dangerous pressure buildup or fires.
When to Call a Professional
If the water heater doesn’t restart after following these steps, or if there are signs of leakage, unusual noises, or a gas smell, it’s time to call a professional plumber. Issues such as faulty thermostats, broken heating elements, or gas line problems may require specialized knowledge and tools to fix safely.
Request Professional Water Heater Service
Our team provides the expert diagnostic tools needed for a lasting fix. Contact us to book an appointment and keep your hot water system running efficiently.