Hot water systems do not fail randomly. There is always a reason behind the issue. Based on our 30 years of experience as a hot water Melbourne plumber, we’ve found that most issues fall into these three common categories:
Electric Systems
Electric hot water units often stop working due to a tripped circuit breaker or safety switch. If the power is still on but the water is cold, the issue may be a faulty heating element or a worn-out thermostat that requires professional replacement to restore your morning comfort.
Gas Systems
Gas systems commonly fail when the pilot light goes out. This can happen due to a faulty thermocouple or fluctuations in the gas supply. If you notice a gas smell, turn off the gas supply immediately and call a licensed plumber to inspect the line.
General Wear and Tear
Over time, Melbourne’s water can leave sediment buildup inside your tank, which reduces heating efficiency and tank capacity. Leaks, ageing components, or incorrect thermostat settings can also lead to inconsistent or lukewarm water.
Quick Checks You Can Do Before Calling a Plumber
Before you worry about a total system replacement, there are a few simple, safe checks you can carry out yourself. Sometimes the fix is as simple as a flick of a switch!
Check Your Power and Gas Supply
Make sure to check your gas valve is in the "On" position and your electrical switchboard hasn't tripped. If the gas is off, your system simply can’t ignite.
Reset the Circuit Breaker (Once Only)
If you find a tripped switch, you can reset it one time. If it trips again immediately, stop. That simply means there is a serious electrical fault that needs a professional hot water plumber.
Inspect the Pilot Light
For older gas storage systems, check the small viewing window. If the flame is out, your water won't heat. Refer to the manufacturer's instructions on the panel for safe relighting.
Confirm the Thermostat Setting
Look over your thermostat if it is set between 60°C and 65°C. Hot enough to kill bacteria like Legionella, but not so hot that it causes instant scalding.
Look for Visible Leaks
Take a quick walk around the unit. If you see water pooling at the base or dripping from the seams, your tank may have a structural crack or a failed internal cylinder.
Test the Pressure Relief Valve
Gently lift the lever on the Pressure Temperature Relief (PTR) valve. It should release a short burst of water. If it’s stuck or constantly running, the valve needs replacing.
Expert Advice: If the problem persists after these basic checks, it’s time to call in the experts. Forcing a faulty system to run can lead to much higher repair costs or even a dangerous burst tank. Your safety is our priority.Â
When to Call a Professional Plumber
While basic troubleshooting is helpful, there is a clear line where safe DIY ends and risky, unlicensed repairs begin. If you notice any of the following warning signs, do not delay. Your system is likely in a state of failure that requires a licensed hot water plumber.
Gas Smells or Hissing Sounds
When you detect a smell of rotten eggs or hear hissing near your unit, shut off the gas valve immediately.
Repeatedly Tripping Circuit Breakers
A breaker that trips a second time after a single reset means you have a short circuit or a grounded heating element.
Continuous Leaking
If you have ever seen your hot water system that discharges water constantly, not just during a heating cycle, it means the valve has failed, or the internal pressure is dangerously high.
Strange Banging or Rumbling Noise
Hearing a strange bang or rumbling sounds in your unit indicates that steam bubbles are exploding through heavy sediment buildup at the bottom of your tank
Visible Tank Damage or Bulging
 If you notice the outer jacket of your tank, and it looks swollen or has visible creases, the internal cylinder is under extreme stress and could burst at any moment.
Water Pooling at the Base
While a small drip might be a valve, a pool of water usually means the steel tank has rusted through and requires a registered plumber’s attention.
Unknown Error Codes
Modern continuous flow gas heaters will display digital codes (like "Error 11" or "Error 12"). If you don't recognise the code, it’s time for a professional diagnostic check.
Critical Safety Tip: Never attempt to remove the access covers or repair the internal wiring of an electric hot water system yourself. These units carry a high voltage of 240V that can be extremely dangerous or fatal if handled by anyone other than a qualified professional.
