How to Turn On a Geyser: Gas, Electric and Instant
The first cold morning of winter is when everyone asks how to start the geyser again. These are the safe steps for a gas tank geyser, an instant gas geyser and an electric geyser, plus the right settings and how to switch off.
Updated 11 November 2026
Before you switch on: three safety checks
- Smell: if you smell gas near the geyser, do not light anything. Close the gas valve, open windows and call a gas fitter.
- Water: the tank must be full. Open the cold water inlet and a hot tap in the house, and wait until water flows from the hot tap without spitting air.
- Flue and wiring: for gas, the flue pipe must be clear and lead outdoors. For electric, the socket or breaker must be dry and earthed.
If the geyser was off all summer, these checks matter most. Read which geyser is safe for the full list.
How to turn on a gas geyser with a pilot
Most tank gas geysers and gas + electric geysers, such as the Nasgas DEG series, use a pilot flame and a gas thermostat knob. The usual steps are:
- Open the main gas valve to the geyser.
- Turn the thermostat knob to the pilot position.
- Press and hold the knob (or pilot button). This lets gas reach the pilot.
- Light the pilot with the ignition button, a long lighter or a match through the burner window.
- Keep holding for 20 to 30 seconds so the thermocouple heats up.
- Release slowly. If the pilot stays lit, turn the knob to the temperature you want, and the main burner will light.
If the pilot goes out when you release, wait a few minutes for the gas to clear and try again. Some models, such as the Super Asia GEH AI range, list auto ignition, so you press a button instead of using a lighter. Always follow the steps printed on your geyser's label.
How to start an instant gas geyser
- Fit fresh batteries in the battery box, or plug in the adapter if your model has one.
- Open the gas valve.
- Open a hot water tap. The igniter clicks and the burner lights by itself.
- Set the gas knob and water knob for the temperature you like.
- Close the tap and the flame goes off.
If it clicks but does not light after a cylinder change or a long break, there may be air in the gas pipe. Open and close the hot tap a few times to let gas reach the burner. If it still will not light, call service. More about these models: tankless geyser guide.
How to switch on an electric geyser
- Make sure the tank is full of water (see the checks above). Never switch on an empty electric geyser; the element can burn out.
- Switch on the geyser breaker or socket.
- Check the indicator light comes on.
- Set the thermostat knob or the display to the temperature you want.
- Wait. A 10 to 15 litre fast geyser is ready in about 15 to 30 minutes; a 50 litre tank takes longer.
Models with three power levels, such as Canon EWST-50-3P 50 Litre Electric Geyser and Nasgas NEG-505 Plus 50 Litre Electric Geyser, let you choose 800, 1200 or 2000 W. Smart models such as Midea D50-20EFG 50 Litre Electric Geyser can be switched on from a phone app.
Geyser settings: the right temperature
For most homes, a setting around the middle of the dial, roughly 50 to 60 degrees C, is hot enough for bathing and kind to the tank. Turn it lower in milder weather and a little higher in the coldest weeks.
- Gas geyser thermostat: turn from high to low or medium once the tank is hot. A lower setting burns less gas.
- Electric geyser: a lower setting means the element switches on less often.
- Instant gas geyser: use less gas and less water flow together for a gentle, steady temperature.
Scalding is a real risk for children and older people, so do not keep the dial at maximum. Saving tips: geyser gas saving tips.
How to turn off a geyser, and should you switch it off daily?
- Gas tank geyser: turn the thermostat knob to pilot to keep only the small flame, or to off and close the gas valve if you will be away.
- Instant gas geyser: it switches off by itself when you close the tap. Close the gas valve at night if you like.
- Electric geyser: switch off at the breaker or use a timer.
Switching off when you do not need hot water saves gas and electricity, because the tank loses heat all day. Many families heat for an hour before the morning bath and again in the evening. A geyser timer does this for you; see the geyser parts guide.
When the geyser will not start
- Gas pilot will not stay lit: weak gas pressure, a draught, or a worn thermocouple.
- Instant geyser clicks but no flame: weak batteries, air in the gas pipe, or low water flow.
- Electric geyser light on but no hot water: thermostat or element fault.
- Breaker trips: stop and call an electrician.
Working through each fault is covered on geyser problems and fixes.
Turning on a geyser on an LPG cylinder
Many homes without Sui gas run their geyser on an LPG cylinder. The steps are the same, with three extra checks:
- Use a proper LPG regulator and a hose rated for gas, and check the joints with soapy water.
- Make sure the geyser is set for LPG. Canon IGWH and CTFT models list both natural gas and LPG, but the fitter may need to set the jet or nozzle for your gas.
- After you change a cylinder, give the pilot or burner a little longer to light, because air has entered the pipe.
Keep the cylinder outside the bathroom, upright and away from heat. If the flame is yellow and smoky, stop and get the setting checked.
