Some gas hot water systems need mains electricity, while others do not. Gas heats the water; electricity may operate the ignition, sensors, controls and combustion fan. Check the specifications for your exact model.
Which systems require electricity?
Most continuous-flow gas hot water systems require mains power. When a hot tap opens, electricity commonly powers:
- the water-flow sensor
- electronic burner ignition
- flame and safety sensors
- temperature controls and the control board
- a combustion fan, where fitted
Without power, the burner usually cannot start.
Some gas storage systems operate without mains electricity because they use a standing pilot light and mechanical gas control. However, storage models with electronic ignition, powered controls or fan-assisted flues still require power. Less common appliances may use batteries or water-powered ignition.
Will it work during a blackout?
A mains-powered gas water heater generally will not heat water during a blackout. A storage system may still supply water already heated in its tank, but it will not reheat until power returns.
A non-powered storage model with a standing pilot may continue operating if its gas and water supplies remain available. Do not assume this from the system’s appearance; confirm it in the manufacturer’s manual.
How to check your system safely
- Read the accessible rating label without removing a cover. Look for a voltage or electrical supply requirement.
- Use the model number to check the manufacturer’s manual or specifications.
- Ask the manufacturer or a qualified technician if the information is unclear.
Do not open the casing, bypass safety controls or alter gas or fixed electrical connections. If you cannot confirm the appliance’s power requirements safely, contact our Sydney plumbing team for assistance.