TL;DR
- No hot water at all: Usually a failed element or thermostat (electric/heat pump), an ignition fault (gas), or a failed booster/circulation issue (solar)
- Hot water turns cold quickly: Usually a failed dip tube letting cold water mix into the tank too early
- Lukewarm or weak hot water: Usually a faulty tempering valve, heating component, PRV, or pipework restriction
- Breaker keeps tripping: Check for water near the electrical section first. If there’s moisture, it’s likely a plumbing fault; if not, it’s likely electrical
- Who fixes it: Most of these, plumbing, gas, or unit-level electrical work, can be handled by one licensed plumber with the right endorsements. Fixed wiring and switchboard faults still need an electrician
- Not sure what’s wrong? Tell 1Touch your system type and symptoms. We’ll identify the fault and handle it, most often in one visit
The right fix for your hot water system not working needs the right diagnosis, which can be tricky since the signs often overlap. For instance, the same problem, like no hot water at all, can be a failed heating element, an ignition fault, or a failed boost element, and which one it is depends on your system type.
That’s why it helps to start by identifying your system type and the basic components it has. It will tell you which of the problems and fixes we share below even apply to you, and who do you need to call to fix it – plumber, electrician, or a gas fitter.
Identify Your Hot Water System Type
If you already know what hot water system is installed in your home, you can skip this step.
System Type | How to Tell |
Electric storage | Cylindrical tank, usually indoors or in a cupboard, no gas smell or flue, single power cable running to it |
Gas | Tank or continuous flow unit with a gas line and flue, often mounted outside or on an external wall, may have a pilot light or ignition display |
Solar | Roof-mounted panels or collectors connected to a storage tank, tank may be on the roof or at ground level, often has a separate boost switch or booster unit |
Heat pump | Compact unit with a visible fan on top, sounds similar to an air conditioner when running, usually installed outdoors |
Why Your Hot Water System Is Not Working (& The Fix It Needs)
No Hot Water at All
From our experience repairing hot water systems throughout Townsville, when there’s no hot water at all in the taps, it’s usually because of a faulty or failing heating component. What that component might be differs by system type.
Electric or heat-pump systems: A failed heating element or thermostat is most likely the cause. Scale can build up around the element and reduce its ability to transfer heat, while a faulty thermostat may stop the element from switching on at the right temperature. To fix it, a plumber would test the heating components (element or thermostat) and replace them. Similarly, heat-pump systems can develop faults with the controller, sensors, or backup element, so the failing component needs to be correctly identified by a plumber before replacing anything.
Gas systems: If the unit has gas but still can’t ignite the burner, it points to a problem with the ignition system, flame sensor, gas supply, or other burner controls. A licensed gas professional can identify the failed component and repair or replace it.
Solar systems: These systems rely on an electric or gas booster when solar energy cannot provide enough heat. If the booster has failed, the fault follows the relevant electric or gas system. If the booster is working, the fault could instead be in the solar side, such as the circulation system, pump, sensors or collector circuit. A plumber with a restricted electrical licence (as 1Touchs’) can test the circulation and collector components and repair the failed part.
Water Starts Hot, Then Turns Cold Quickly
If you have a storage-based system, and you get a short burst of hot water before it turns cold, the system may be heating water normally but failing to keep the hot and cold water separated inside the storage tank.
The likely cause is a failed dip tube, which, when working normally, carries incoming cold water down to the bottom of the tank. When the tube cracks or breaks, cold water can enter near the top and mix with the hot water waiting to leave the tank.
This results in a much shorter hot-water supply. You can start with a genuinely hot shower, only for the temperature to fall rapidly as cold incoming water mixes into the hot layer.
To fix this, the plumber replaces the dip-tube, restoring cold water delivery to the bottom of the tank, keeping it away from the hot water at the top..
Lukewarm Water Throughout
Lukewarm water throughout the house can point to two different problems: the system may not be heating the water properly, or a valve may be mixing in too much cold water before it reaches the taps. Let’s discuss them one by one.
- The tempering valve may be mixing in too much cold water. The valve controls how much hot and cold water reaches your taps. If it gets stuck, clogged with scale,, it can mix too little hot or too much cold water, making your tap supply lukewarm. A plumber can check the valve and repair or replace it if needed.
- The thermostat or heating element may not be working properly. In systems with separate upper and lower heating elements, a failed lower element can leave much of the tank cold, which means the hot water gets diluted and stays lukewarm when it reaches the taps. A faulty thermostat can cause a similar problem by shutting the heating off too early, making the system register the water as hot when it has not reached the right temperature. The fix involves testing the element and thermostat and replacing the faulty component.
Check the water pressure as well. If the water is both lukewarm and weaker than usual, the tempering valve becomes more likely to be the problem. If the pressure is normal but the water stays lukewarm, the thermostat or heating element is more likely to be at fault.
Weak Hot-Water Pressure
If your cold-water pressure is normal but the hot water comes out slowly, the problem is likely somewhere in the hot-water supply rather than the heating system.
- A faulty PRV, valve or blocked pipe can restrict the flow. Scale, debris or a faulty valve can stop enough water from reaching your taps. A plumber can find the restriction and repair or replace the affected part.
- The tempering valve can also reduce the flow. If it is even partially blocked, it can cause both weak pressure and lukewarm water. This can also explain why the two symptoms sometimes appear together.
Depending on where the blockage or fault is, a plumber may clean or replace a valve, clear the pipework, or repair the affected fixture.
Only One Tap or Shower Affected
If one outlet has suddenly lost hot water while the others are working normally, the hot-water system itself is probably not the first place to look.
It’s most probably a local mixer or cartridge fault preventing hot water from reaching that fixture properly. A worn cartridge, internal blockage, or failed mixer can allow cold water to cross into the hot side or restrict the hot-water flow.
The fix is usually local to the fixture. A plumber can check the mixer or cartridge, clean it if possible, or replace it if it has failed.
Breaker or Safety Switch Keeps Tripping
A breaker or safety switch that keeps tripping definitely means something is wrong, but not always electrical to begin with. So first, you need to check whether there is any water around the electrical parts of the system.
- If you can see water or moisture around the electrical section, the trip may be caused by a plumbing fault. A leak can reach the electrical connections and cause the breaker or safety switch to cut the power. The leak needs to be dealt with before the system is switched back on.
- If you don’t find any water around the system, the problem is more likely to be electrical. A failed heating element, thermostat, wiring fault or another electrical component can cause the breaker or safety switch to trip.
- Don’t keep resetting it. If it trips again after being reset, leave it off and have the system checked by a licensed plumber.
System Displays an Error Code
An error code can give you a useful clue about what has gone wrong, but its meaning varies depending on the system and model.
- Electric and heat-pump systems can show codes for faults with the heating element, sensors, temperature or controls. Check the code against your model’s manual rather than relying on a generic error-code list.
- Gas systems can show codes for ignition, flame, gas supply or water flow problems. The code, along with how the system is behaving, can help narrow down the cause.
- Solar systems can show codes for the controller, sensors or circulation system. The problem may be on the solar side even when the tank and booster are working normally.
- Take a photo before calling for help. Save a clear photo of the error code and the model number. Also note when the code appears, such as when you turn the system on or open a hot tap. This gives the technician useful information before they inspect the system.
Who Should You Call: Plumber or Electrician?
Once you have matched the symptom to the likely fault, the answer to “who’ll fix it” gets much simpler. The summary we’ve put together below will help you figure it very easily:
Problem | Who typically fixes it |
Dip tube, tempering/mixing valve, PRV, pipework, mixer/cartridge, relief valve or water leak | Plumber |
Heating element, thermostat or unit-level electrical component | Plumber with the appropriate restricted electrical licence, or an electrician |
Gas ignition, gas valve or gas-specific fault | Licensed gas fitter |
Fixed wiring, switchboard fault or switchboard-level trip | Electrician |
The good news is, you don’t have to call all these different tradesmen out separately.
At 1Touch our plumbers hold restricted Gas and Electrical license (as required by QBCC), allowing us to cover specific electrical and gas work associated with hot-water systems. The scope is limited, so fixed wiring and switchboard faults still require the appropriate electrical professional.
But for all of the hot-water problems we listed above (and the ones we might have missed), whether the cause is electrical or gas-related, our expert team can fix it for you the same day you contact us.
Final Thoughts
When your hot water stops working, identify correctly your system type and the symptom. Then call us at +61 7 4751 7600 and tell our team what type of system you have, what has gone wrong, and whether you have noticed a leak, tripping breaker, or error code.
From there, our team will ask you a few questions to narrow down the likely cause and determine whether it needs one of our licensed plumbers, or a separate electrician.
If we’ve missed what you’re experiencing in our list above, call us anyway. Most hot-water faults fall within what we can diagnose and fix directly, and if it turns out to be something outside our scope, like a fixed-wiring or switchboard-level issue, we’ll point you in the right direction.
Contact 1Touch Plumbing and let our licensed professionals take it from there.
FAQs
Why does my hot water work for a few minutes and then turn cold?
A failed dip tube can cause this in storage-based systems. When the tube breaks, cold water enters the tank at the top rather than at the bottom, mixing with the hot water at the top. A plumber can replace the dip tube and restore the tank’s normal hot-water draw.
Why does my hot-water breaker keep tripping?
First, look for water around the electrical section of the system. A leak can allow moisture to reach electrical components, causing the protection device to trip. If there is no water present, a failed element, thermostat, wiring, or another electrical component may be responsible. If the breaker trips again after a reset, leave it off and have the fault professionally diagnosed.
What should I do if my hot-water system is leaking?
If it’s dripping from the relief-valve discharge pipe, leave it alone. That valve releases water on purpose to stop the tank from over-pressurising, and blocking or capping it is dangerous, not a fix.
If the leak is coming from somewhere else, such as a valve, fitting, or connection, locate the water isolation valve if you can safely access it, shut off the supply, and arrange a plumber’s inspection. A leaking valve or connection is often repairable, but water coming directly from the tank body itself usually means the cylinder has reached the end of its service life.
Can the same plumber fix a leak and an electrical fault?
Sometimes, yes. A plumber with the appropriate restricted electrical authorisation can perform specific electrical work associated with hot-water systems. However, a restricted license only covers the work stated on the licence. Fixed wiring and switchboard-level faults require the appropriate electrical professional.
