A gas geyser that stops working is frustrating, especially for a household relying on it daily for hot water. The good news is that diagnosing the issue usually follows a fairly predictable path — a handful of specific causes account for the large majority of “not working” cases, and working through them in order makes it much easier to pinpoint what’s actually wrong.
Gas Supply Issues
Start by checking whether the gas supply to the geyser has been accidentally switched off or interrupted — this happens more often than people expect. If the supply is on but the geyser still won’t light, low gas pressure could be the cause; contacting the gas supplier is the next step if pressure seems to be the issue elsewhere in the house too.
Pilot Light Problems
If the pilot light — the small flame that lights the main burner — has gone out, the geyser simply won’t operate until it’s relit following the manufacturer’s instructions on the unit or in the manual. If relighting doesn’t hold, the thermocouple (the safety device that detects the pilot flame) or the pilot assembly itself may be affected by dust, debris, or corrosion, in which case cleaning or replacing these parts becomes necessary.
Thermostat Problems
If the geyser is running but not reaching the temperature it’s set to, a malfunctioning thermostat is a common cause, and replacement is usually the straightforward fix.
Gas Valve Issues
A faulty gas valve can prevent gas from reaching the burner at all, even with supply and pressure otherwise normal. This is a component that should be replaced by a trained technician rather than attempted independently.
Ignition Issues
For geysers with electronic ignition rather than a standing pilot, a fault in that ignition system will prevent the burner from lighting and typically needs repair or replacement by a technician.
Ventilation and Exhaust Issues
Blocked ventilation can allow carbon monoxide to build up, which may trigger the geyser to shut itself off as a safety measure — checking that vents are open and unobstructed is worth doing before assuming a component has failed. A blocked exhaust flue can cause the same kind of safety shutdown, and clearing any blockage there restores normal operation.
Water Flow Problems
Low water pressure can prevent some geysers from igniting at all, since many models rely on detecting adequate flow as part of the ignition trigger. Checking water pressure and supply rules this out as a cause before looking elsewhere.
Age and Maintenance
A geyser that hasn’t had regular maintenance can accumulate dirt and debris that affects performance over time. Age itself is also a factor — as components wear, reliability and efficiency both decline, and at a certain point replacement becomes more sensible than continuing to repair an ageing unit.
When to Stop Troubleshooting and Call a Technician
If there’s a smell of gas, visible water leaking from the tank, a burning smell, or the geyser still doesn’t respond after checking power/gas supply and the pilot light, that’s the point to stop testing the unit yourself and bring in a professional rather than continuing to investigate further.
How to Diagnose a Geyser That Isn't Working
- Rule out a power or gas supply issue: Confirm the electric switch is on and the breaker hasn't tripped, or that the gas valve is open and supply pressure is normal elsewhere in the house.
- Check the pilot light: For gas geysers, see if the pilot light is out. If so, follow the relighting procedure printed on the unit or in the manual.
- Look for visible leaks or damage: Check around the base and connections for water pooling, which can indicate a tank or valve failure requiring professional repair.
- Test the reset or safety cut-off button: Press the reset button if present, only after confirming the unit has cooled and there's no gas smell.
- Check for error indicators: Newer digital or smart geysers often display an error code or blinking light — note this code, since it narrows down the fault for a technician.
- Contact a technician if the geyser still won't respond: A complete failure after these checks usually points to an internal component fault — thermostat, valve, or wiring — that needs professional diagnosis.
Frequently Asked Questions
What should I check first if my geyser isn't working at all?
Confirm the power switch and circuit breaker are on for electric models, or that the gas supply valve is open and the pilot light is lit for gas models. A large share of "not working" calls turn out to be a simple power or gas supply issue rather than a component failure.
Why did my geyser suddenly stop working after gas load shedding?
Some pilot lights go out during a gas supply interruption and don't relight automatically once gas returns, leaving the geyser appearing "dead" until the pilot is manually relit.
Could a tripped circuit breaker be the reason my electric geyser stopped working?
Yes — electric geysers draw significant current, and a tripped breaker or blown fuse is one of the most common reasons for a sudden, total loss of power to the unit.
When should I call a technician instead of troubleshooting myself?
If you smell gas, see visible water leakage from the tank, notice burning smells, or the unit doesn't respond after checking power/gas supply and pilot light, stop troubleshooting and call a technician rather than continuing to test the unit yourself.