7 Steps to Reset a Gas Hot Water System Safely

Last Updated: November 7, 2026

Table of Contents

• Reset, Relight or Restart: Know Which One You Need
• Where Is the Gas Hot Water System Reset Button Located?
• Step-by-Step: How to Reset a Gas Hot Water System
  • Step 1: Turn Off the Gas Control and Power
  • Step 2: Wait, Then Restore the Gas Supply and Power
  • Step 3: Press the Reset Button and Test the Hot Taps
• How to Relight a Gas Hot Water System Pilot Light
  • Holding the Pilot Control After Ignition
• How Long Does a Gas Hot Water System Take to Reheat?
• Gas Hot Water System Troubleshooting When a Reset Fails
  • What the Failure Pattern Tells You
  • Storage Tank vs Continuous Flow: Different Reset Behaviour
  • When to Stop Troubleshooting
• Gas Leaks and When to Stop and Call a Licensed Plumber
• Book a Same-Day Hot Water Check With Northern Rivers Hot Water
• Frequently Asked Questions

Reset, Relight or Restart: Know Which One You Need

If your gas hot water has stopped working, knowing how to reset gas hot water system controls starts with one question: what actually failed?

Here is the difference in plain terms:

• Reset clears a safety lockout on a system with electronic ignition. The gas and power stay on.
• Relight restarts a standing pilot flame that has blown out.
• Restart brings the whole unit back after a gas interruption or a full power cut.

Many "dead" systems only need one of these three. Others have a real fault. This guide shows you how to tell them apart, step by step.

If you are unsure which situation you are in, what to do when your hot water system breaks down walks through the wider checklist before you touch anything.

Where Is the Gas Hot Water System Reset Button Located?

The reset button sits on the gas control valve, behind the access panel on the lower front or side of the tank.

Where to look, in order:

1. Outdoor storage tank: a hinged or screwed panel near the base. The valve has a knob, a red or black reset button, and a small status light.
2. Continuous flow unit: open the front cover. The reset button is usually a small recessed button beside the display.
3. Indoor or enclosed systems: check the same lower panel area, but switch off the power at the isolator first.

The gas hot water system reset button location varies by brand, and the control valve fitted to your unit determines which reset sequence applies.

A common pattern across the main brands:

• Rinnai: storage tanks often use a control valve with a combined gas knob and reset button under a screw-off cover; continuous flow units (Infinity and similar ranges) typically have a digital display with a recessed reset button and a two-digit error code window.
• Rheem: storage tanks frequently use a Robertshaw-style control valve with a push-button piezo igniter and a separate reset button; continuous flow units usually show error codes on the display and reset via a button on the control panel.
• Dux: storage tanks commonly use a control valve where the reset button is a small red or black button on the valve body; continuous flow units vary, so read the label before assuming a reset button exists.

Watch out: if the label is faded or missing, do not guess the sequence from a video for a different brand.

Step-by-Step: How to Reset a Gas Hot Water System

This sequence suits most electronic-ignition storage tanks. Total time is about 20 minutes, plus reheating.

Step 1: Turn Off the Gas Control and Power

Turn the gas control knob to the off position, then switch off the electrical supply at the isolator or circuit breaker. Wait a full 30 seconds.

This clears the safety control and lets the system start clean. Do not skip the wait.

Step 2: Wait, Then Restore the Gas Supply and Power

Turn the gas supply back on at the control knob, then restore power. Listen for the ignition sequence. Many units show a flashing light while they try to light.

Step 3: Press the Reset Button and Test the Hot Taps

Press the reset button once, firmly. Then open a hot water tap and let it run for a minute.

Watch out: if the system locks out again straight away, stop. Book a hot water repair and fault diagnosis rather than pressing the button a third time.

Here is the reset sequence at a glance, from shutting off the gas to testing the hot taps.

Step	What to do	Time or note
1	Turn gas control knob to off, switch off power	Wait a full 30 seconds
2	Restore gas supply, then restore power	Listen for the ignition sequence
3	Press reset button once, firmly	Then open a hot tap for a minute
Whole job	Reset an electronic-ignition storage tank	About 20 minutes, plus reheating
If it locks out again	Stop, do not press reset a third time	Points to a real fault

How to Relight a Gas Hot Water System Pilot Light

Learning how to relight a gas hot water system pilot light is straightforward on older units with a standing pilot. Newer electronic units have no pilot flame at all, so skip to the reset steps above.

The relight sequence:

1. Set the control knob to pilot position.
2. Press and hold the control knob down.
3. Press the ignition button, or hold a lighter to the pilot burner, until the pilot flame is steady.
4. Keep holding the knob for about 30 seconds after the flame catches.
5. Release slowly. If the flame goes out, wait five minutes and try again.

Holding the Pilot Control After Ignition

Hold the pilot control for at least 30 seconds after ignition. This lets the thermocouple heat up and tell the safety control the flame is lit.

If the pilot keeps dying when you release the knob, the thermocouple is the likely culprit. That is a job for a licensed plumber.

How Long Does a Gas Hot Water System Take to Reheat?

Most storage tanks take 30 to 60 minutes to reheat after a reset or relight.

Continuous flow systems are different. They heat on demand, so hot water returns within seconds of a successful restart.

If hot water keeps running out mid-shower rather than just once, the cause is usually something else. Our guide on stopping hot water going cold mid-shower covers the common reasons.

Gas Hot Water System Troubleshooting When a Reset Fails

When a reset fails, work through the basics before calling anyone. Gas hot water system troubleshooting starts with three checks: gas on, power on, and controls set correctly. But the pattern of failure matters more than the checklist itself, because it tells you whether you are dealing with a nuisance lockout or a genuine fault.

• Check the gas supply. Is the shut-off valve open? Has another gas appliance, a cooktop or heater, stopped working too? If more than one appliance is out, the problem is upstream of the heater and you should contact your gas distributor rather than the plumber.
• Check the power cycle. Switch the isolator off, wait 30 seconds, and switch it back on. Electronic ignition units need a clean power cycle to clear a lockout.
• Check the status light. A steady light usually means ready. A slow flash often means a lockout that a reset can clear. A rapid flash or a repeating pattern usually indicates a specific fault code, count the flashes and note the pattern before you reset again.

What the Failure Pattern Tells You

A single lockout after a gas interruption or power cut is normal and a reset should clear it. The pattern to watch for is repetition:

• Pilot lights but goes out when you release the knob: the thermocouple or flame sensor is not proving the flame. This is a common failure on older standing-pilot units and needs a licensed plumber to replace the sensor.
• Pilot will not light at all: check that gas is actually reaching the valve. If the igniter clicks but there is no flame, and other gas appliances work, the fault is in the heater's gas valve or ignition circuit.
• Reset appears to work but the burner never fires: the unit may be in a safety lockout that only clears after a longer wait, or the control board may have failed. Do not keep pressing reset.

Storage Tank vs Continuous Flow: Different Reset Behaviour

Storage tanks lock out and reheat slowly, so a successful reset may not show hot water at the tap for 30 to 60 minutes.

If the code returns after a reset, the unit has found a fault. Do not keep clearing it. Two failed resets in a row is the practical limit, after that, the probability of a genuine component failure is high enough that further attempts waste time and risk damaging the ignition circuit.

When to Stop Troubleshooting

Stop and call a licensed plumber if any of the following apply:

• You smell gas at any point.
• The reset button feels loose, stuck or does not click.
• You see water pooling around the base of the tank or corrosion on the valve.

Gas appliance work should be left to a licensed plumber, so anything beyond the external reset and relight steps is best left to a professional.

Gas Leaks and When to Stop and Call a Licensed Plumber

Stop work immediately if you smell gas. Do not press any buttons, do not use a lighter, and do not switch anything on or off.

What to do instead:

• Turn off the gas at the shut-off valve if you can reach it safely.
• Open doors and windows.
• Leave the area and keep others away.

Gas appliance work should be carried out by a licensed plumber. If you need urgent help, our emergency hot water callout can assist.

Book a Same-Day Hot Water Check With Northern Rivers Hot Water

Still no hot water after a reset? It is time to bring in a licensed plumber.

When you book, you get:

• A same-day callout where available
• Clear, upfront pricing before work starts
• A licensed, insured plumber on site

Visit our gas hot water repairs and servicing page for current details and to arrange a visit. Get started with Northern Rivers Hot Water and have your hot water running again.

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A failed reset usually means a part has worn out, and the sooner it is diagnosed, the cheaper the fix tends to be.

Frequently Asked Questions

Is it safe to reset a gas hot water system myself?

A single reset is safe for most homeowners: turn the gas control to off, cut the power at the switch, wait, then restore both and press the reset button once. What is not safe is repeated resetting. If the system shuts down again straight away, stop. A repeating trip points to a failed thermocouple, a blocked flue or a gas supply fault, and each reset releases unburnt gas. If you smell gas at any point, turn the gas off at the shut-off valve, ventilate the area and call a licensed plumber.

Why is my gas hot water system not heating after a reset?

Check three things in order. First, confirm the gas supply is actually on: test another gas appliance such as a cooktop. Second, check the pilot flame or ignition status light on the control panel; a cold pilot means the system needs relighting. Third, look at the electrical supply, because most gas units still need power for the ignition and thermostat. If gas and power are both present and the water stays cold, the fault sits inside the unit and needs a licensed technician.

How long does a gas hot water system take to reheat after a reset?

A storage tank typically takes 30 to 60 minutes to bring a full cylinder back to temperature, and longer in cold weather or after heavy use. Continuous flow systems deliver hot water within seconds of a tap opening, so if nothing arrives after about a minute, the unit has not fired and needs troubleshooting rather than more waiting. Run a hot tap for a few minutes before assuming the reset failed.

What should I do if my gas hot water system keeps shutting off?

Stop resetting it. A unit that trips repeatedly is protecting itself from a real fault, commonly a dirty flame sensor, a failing thermocouple, a flue blockage or incorrect gas pressure. Repeated resets can flood the combustion chamber with gas. Turn the system off at the gas control and the power switch, then book a licensed plumber. Northern Rivers Hot Water can help with this situation.