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Introduction to Common Water Heater Problems

A tankless water heater is crucial for daily activities like showering and washing dishes. But when hot water heater issues occur, they can interrupt the water flow, leaving your household without necessary hot water.

At Leichhardt Plumbing, we specialise in diagnosing and repairing all types of hot water systems.

This article outlines solutions to common hot water system issues, aiming to restore your system’s efficiency.

A clear indicator of water heater problems is the absence of hot water from faucets and showerheads. Other symptoms include:

  • Gurgling or hissing noises from the water heater when there’s no hot water
  • Cloudy water coming out of your hot water tank
  • Lower than normal hot water flow rate
  • Leaking or rust around the tank

We’ll guide you through troubleshooting for both gas and electric water heater models.

Basic DIY skills and correct safety measures can enhance your water heater’s performance. However, if problems persist, Leichhardt Plumbing’s gas professionals should be contacted. Most residential water heater issues can be resolved with the right diagnostics and parts.

Checking Electric Water Heaters

If your electric hot water heater isn’t heating correctly, several components warrant checking.

Check the Thermostats

Electric water heaters have two key components: an upper and a lower element. Incorrect thermostat settings or issues with the high-temperature limit switch can affect function.

The upper thermostat controls the upper heating system, and the lower thermostat influences the lower heating element. Aim for a temperature range between 49-60°C (120-140°F).

Test the Heating Elements

Once your circuit breakers are checked, use a multimeter to measure the heating elements’ resistance. Ideal readings are between 10-16 ohms. If the meter reads infinity or zero, likely the element is burnt out and needs replacing.

Reset Tripped Breakers

Examine the main breaker panel for tripped breakers connected to your electric hot water system. Reset any tripped breaker to the ON position.

This action should restore the unit’s power.

If resetting the breaker doesn’t work, contact Leichhardt Plumbing. Our technicians can troubleshoot any issue with your electric hot water heater.

Testing Thermostats and Heating Elements

Thermostats and heating elements play a critical role in regulating the temperature of your electric water heater. Testing them is an important troubleshooting step if you’re not getting enough hot water.

Testing the Thermostat

Start by ensuring you turn off power to your water heater before proceeding with any checks. Remove the access panel and locate the thermostats. Test for continuity by applying the multimeter probe leads to the terminals of each thermostat.

A functioning thermostat shows around 13 ohms resistance, signifying it’s closed and calling for heat. No continuity indicates an open thermostat, which won’t trigger the heating element and may require professional replacement.

Checking the Heating Element

Disconnect power and remove the faulty element to test its resistance. A reading outside the 10-16 ohms range signals damage and the element should be replaced.

Place one probe on each screw terminal; the element should measure properly. A good element should show an ohms resistance of around 10-16.

Avoid contact between the element wires during testing. A licensed electrician should install replacement elements.

If new thermostats and elements fail to fix the problem, Leichhardt Plumbing can handle both electric and gas heater issues.

Diagnosing Issues with Gas Water Heaters

Gas hot water heaters use a pilot light to ignite the burner; if you have insufficient hot water, a pilot light issue is common.

Here are a few key things to check when diagnosing your gas hot water system problems:

Inspect the Pilot Light

Locate the small pilot light assembly at the base of the tank. Typically this involves pushing in and holding the pilot button while triggering the igniter.

After the pilot sustains its flame, you can let go of the button and your heater gas will remain lit.

Check the Gas Supply

To address the issue, ensure the gas supply valve is open and the meter indicates gas flow. Attempt to relight the pilot with the gas valve open.

Evaluating the Thermocouple

The thermocouple generates a small electrical current that signals the gas valve to open when heated by pilot flame. Use a multimeter to check for continuity between the thermocouple and gas valve. No continuity could indicate a faulty thermocouple.

If the pilot light continues to go out after checking these components, contact Leichhardt Plumbing. Our gas fitting experts can thoroughly diagnose any issue keeping your gas water heater from producing hot water.

Checking the Pilot Light

If the pilot light on your gas water heater is out, carefully inspect the pilot assembly before attempting to relight it.

Ensure the gas supply valve on the line is open. Then, verify the unit has sufficient gas pressure, ideally at least 18 centimetres of water column, using a manometer.

Inspect the hot water unit for blockages that could impede gas flow to the pilot and main burner. Clear away any debris near the pilot light orifice or main burner with compressed air or a wire brush.

When ready to relight, open the access panel and push in the pilot button. While holding the button in, trigger the igniter to light the pilot flame. This allows the thermocouple to heat up and signal the gas valve to stay open.

Continue holding the button for 30-60 seconds after the pilot lights, then release the pilot button. If the pilot light immediately goes out when the button is released, the thermocouple may need replacement.

When the pilot maintains its flame, replace the access panel and set the gas control to ON to light the main burner. If the pilot extinguishes frequently, Leichhardt Plumbing’s licensed gas fitters can diagnose and fix the issue.

Cleaning or Replacing the Thermocouple

If the pilot light frequently extinguishes after ignition, it may point to a short circuit or the need to clean or replace the thermocouple, which signals the gas valve to open with a small electrical current.

Switch off the gas and carefully clean the thermocouple with emery cloth or steel wool to clear any deposits. Avoid damaging the tip, relight the pilot, and observe if it remains lit.

If cleaning doesn’t help, a new thermocouple corresponding to your heater model is necessary. Disconnect the gas, uninstall the old thermocouple, and install the replacement securely.

Disconnect the gas and carefully unscrew the old thermocouple. Fasten the replacement to the gas valve securely.

If the new thermocouple doesn’t fix the issue, contact Leichhardt Plumbing. Our licenced gas fitters can fully diagnose any pilot light problem on your gas water heater.

Repairing or Replacing Faulty Parts

Several components in your water heater may become faulty over time. Key parts to monitor for potential failure impacting your hot water heater include:

Anode Rod

The anode rod, designed to shut off corrosion, is a sacrificial metal component within the tank. Once it is corroded, it should be replaced—reach out to our service line for support. Indications that it’s time to replace parts in your common hot water heater include water odour akin to rotten eggs or an alarmingly early tank malfunction.

Dip Tube

The dip tube, connected to the cold water inlet, is a crucial plastic component that guides water to your tank’s base, ensuring proper hot water distribution throughout. If it is damaged, replacing the part is essential as a broken dip tube can cause cold water to mix with the hot, resulting in an insufficient hot water supply. Replacements should match the original diameter and length.

Pressure Relief Valve

The pressure relief valve is designed to release excess tank pressure. Select a valve that complies with the hitemperature limit and BTU rating of your heater when performing a replacement. Improper valve replacement can lead to dangerous over-pressurisation.

Consult the Leichhardt Plumbing professionals if you need assistance with water heater repair or replacing faulty components. Our licenced technicians will ensure any replacements adhere to manufacturer specifications for safe operation.

Dealing with Leaks and Pressure Relief Valves

Start by visually inspecting the tank exterior, pipes, and fittings for any water residue.

Wipe the connections dry and monitor to see if moisture returns. Look for tiny pinhole leaks which can slowly drip water.

Manually test the pressure relief valve following the manufacturer’s guidance.

Never ignore a water heater leak or malfunctioning pressure relief valve. Small leaks that persist for a long time tend to worsen and can lead to significant water damage or dangerous pressure buildup. Contact Leichhardt Plumbing immediately to diagnose and professionally repair any leaks or issues with valves on your hot water system.

Flushing Sediment from the Tank

Annual tank flushing can prevent sediment buildup and maintain your water heater’s efficiency. Over time, minerals from your water heater’s supply can collect in the bottom of the tank as sediment. This buildup reduces heating capacity and can disrupt water flow, causing rumbling or popping noises as sediment hardens on the tank walls.

Turn off the power to your electric heater or the gas and pilot light for a gas unit before starting. Fully open the valve to kick off power water egress until it appears clear and without any sediment. Close the valve, refill the tank, and restore power or gas supply when finished.

Flushing your water heater tank is quick and easy maintenance to keep your hot water system operating at optimal performance. Contact Leichhardt Plumbing if you need assistance accessing the drain valve or have any other water heater maintenance needs.

When to Call a Professional

While many common water heater problems can be diagnosed and repaired on your own, there are certain situations where it’s best to call in a professional plumber:

  • You’ve thoroughly checked and troubleshot your system but the issue persists
  • Problems are complicated or beyond your mechanical skill level
  • Replacement parts must adhere to safety ratings or specifications
  • Leaks, pressure problems, or gas issues are involved
  • Tank flush clearing or sediment removal is needed

Leichhardt Plumbing’s licensed technicians can swiftly diagnose and fix any hot water system problem. Contact us at 1300 349 338 or [email protected] to benefit from our extensive plumbing experience, expert advice, or to schedule a service call.


Troubleshooting common water heater problems and knowing when to call a professional can help restore your hot water supply. We hope this guide gave you the key steps for diagnosing issues with electric and gas heaters. As leading plumbers, our qualified technicians are ready to get your hot water flowing again.

Prioritize safety in any water heater troubleshooting; for assistance or complex repairs, call us at Leichhardt Plumbing on 1300 349 338 to arrange service.

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