No Hot Water? Troubleshooting Hot Water System Issues

No Hot Water? Start Here

Before calling a plumber, there are a few quick checks worth doing. Work through these first — they resolve the problem more often than you'd think.

Gas Hot Water Systems — Check These First

Check whether other gas appliances are working. If your stove and heater work but the hot water doesn't, the issue is specific to the hot water system. Check the pilot light if your system has one — older units have a standing pilot that can blow out. Modern systems have electronic ignition that should light automatically but may display a fault code if it can't ignite. Note the fault code and check your manual. Also check that the gas isolation valve on the unit (usually a lever near the unit itself) is fully open.

Electric Hot Water Systems — Check These First

Check your switchboard. Electric hot water systems are often on a dedicated circuit breaker or controlled by an off-peak relay timer. Find the circuit labelled "hot water" on your switchboard and check it hasn't tripped. Reset if required. If it trips again, the element or thermostat has likely failed and a plumber is needed. Also check the power isolation switch on the wall near the hot water unit.

Continuous Flow (Instantaneous) Systems — Check These First

Continuous flow systems require a minimum flow rate to activate. Check that your hot water tap is fully open. In winter, cold supply water temperatures drop significantly — if your unit is set to 50°C and supply water is 8°C, the system has to work harder and may not reach temperature at low flow. Turn up the hot water temperature setting slightly if this happens in cold weather.

When to Call a Plumber

Call ATC Plumbing if the checks above don't resolve the problem, if there's water leaking from the unit, if the water is discoloured or smells, if the pressure relief valve is weeping or running, or if your system is more than 10 years old and not recovering properly. Same-day hot water service across Melbourne's south-east. Call 1300 282 758 — 24/7 for emergencies.

Related reading: opening your hot water relief (PTR) valve