Gas Hot Water Not Working? Causes & Fixes
A gas hot water system not working usually comes down to the pilot, the ignition or the gas supply. Here's what's likely going on, what's safe to check, and how our licensed gasfitters get it heating again.
Why your gas hot water stopped
When gas hot water is not working, the unit has usually lost its flame. The classic symptom is a pilot light that won't stay lit — you relight it, it burns while you hold the knob, then goes out. That points to a thermocouple that's no longer sensing the flame. Other common causes are a gas hot water no ignition fault on an electronic-ignition or continuous-flow unit, a failed gas valve, or simply no gas reaching the unit.
A gas hot water system not working is almost always a repair, not a replacement — the parts involved (thermocouple, igniter, gas valve) are serviceable. But gas work is licensed work, so the diagnosis and repair are a gasfitter's job.
What's probably causing it
Ranked by how often we see it — tell us which sounds like yours and we'll come prepared.
Pilot light won't stay lit
The most common gas fault — a worn thermocouple stops sensing the pilot flame, so the gas valve shuts and the pilot goes out.
No ignition (electronic / continuous flow)
On electronic-ignition and continuous-flow units, a failed igniter, flame sensor or control board means the burner won't fire on demand.
Gas valve fault
A faulty gas control valve can stop gas reaching the burner even when the pilot and igniter are fine.
No gas supply
An isolation valve turned off, a supply interruption, or an empty LPG bottle leaves the unit unable to heat.
Blocked burner or fault code
A dirty burner, blocked flue, or a fault code on a continuous-flow unit can shut the system down for safety.
Gas repairs by licensed gasfitters · safety-checked before we leave.
What's safe to check — and what isn't
A few checks are safe for anyone; the rest is a licensed gas or electrical job.
What's safe to check yourself
- Is the gas on at the isolation valve and the meter?
- Relight the pilot once, per the manufacturer's instructions
- Check an LPG bottle isn't empty
- Note any fault code on the display to tell us
If the pilot won't hold after one relight, it's almost certainly the thermocouple — a licensed repair.
When to call a licensed gasfitter
- The pilot won't stay lit after relighting
- No ignition / no flame on demand
- You smell gas (turn gas off, don't use switches, call)
- Any thermocouple, gas-valve, igniter or burner work
All gas work must be done by a licensed gasfitter — never attempt gas-component repairs.
How our gasfitters fix it
The licensed repair, and the fastest path back to hot water.
We diagnose the exact gas fault — thermocouple, igniter, flame sensor, gas valve or supply — and quote before we start. Thermocouples and igniters are common parts we carry, so a pilot or ignition fault is usually fixed in one visit. All work is done by licensed gasfitters and safety-checked before we leave.
If it's not specifically a gas fault and you just have no hot water at all, our general no hot water guide covers the wider causes.
See also: book a repair · no hot water at all?
Gas Hot Water Not Working? Causes & Fixes questions, answered
If yours isn't here, call — the line's attended 24 hours.
Why won't my gas hot water pilot light stay lit?
Why is my gas hot water not igniting?
Is it safe to relight the pilot myself?
Can you fix gas hot water the same day?
Does gas hot water work need a licensed gasfitter?
What if I smell gas?
Tell us what's happening — we'll fix it
Call the 24-hour line with your suburb and the symptom, or request a quote. We prioritise no-hot-water call-outs and come prepared with the likely parts.