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It’s frustrating when you turn on the tap for hot water and only cold water flows.

When there’s no hot water coming from your system, it can put a wrench in your morning routine and leave you scrambling to figure out the problem. This troubleshooting guide provides a systematic checklist from Leichhardt Plumbing’s expert plumbers to resolve cold water issues effectively.

We address common issues and solutions for gas, electric, and solar water heaters, ensuring you and your family enjoy the comfort of hot water again.

Our guide includes preventative maintenance tips to help avoid cold water issues with your water heater. Taking a proactive approach by inspecting, flushing and servicing your water heater annually can go a long way toward reliable operation.

With 25 years of experience, we ensure optimal performance of all water heater makes and models.

Struggling with cold water issues? Our licensed plumbers are on call 24/7 to restore your hot water supply.

Common Causes of Loss of Hot Water

Having your hot water suddenly stop working can be incredibly inconvenient. Before troubleshooting your specific system, it helps to understand some of the most common reasons hot water may stop flowing in Australian households where water heating accounts for about 21% of energy use.

Issues with electric storage water heaters typically involve the heating element, thermostat, or anode rod. Notably, anode rods typically need replacement every 5-8 years to protect the tank.

The element heats the water while the thermostat controls the temperature. If either fails, you’ll get cold water.

In gas systems, usual suspects include the pilot light extinguishing, a defective gas control valve, or thermocouple sensor issues.

The pilot light ignites the burner to heat water. If it goes out, the system shuts down. The gas valve regulates flow. A malfunctioning thermocouple disrupts temperature monitoring.

The following sections detail step-by-step troubleshooting for electric and gas heaters, addressing frequent cold water causes. Understanding the problem guides solutions.

Electric Water Heater Troubleshooting

Troubleshooting an electric hot water system to get your hot water flowing again can be done in a few straightforward steps:

  1. Check Power Supply - Check your electrical panel for a tripped breaker or blown fuse connected to the water heater and reset or replace as needed.
  2. Inspect Heating Element - Turn off power and remove the access panel. Visually inspect the element for mineral buildup or cracks. Test resistance with a multimeter. Replace if faulty.
  3. Test Thermostat - Verify it’s set to 55°C. Adjust if needed. Test continuity between thermostat wires. Replace thermostat if no continuity.
  4. Flush Tank - Drain a few gallons from the tank’s drain valve to remove sediment. Close drain and refill tank.
  5. Replace Anode Rod - Unscrew the anode rod near the top of the tank. Replace if excessively corroded. Lubricate new anode threads and reinstall.
  6. Contact Electrician or Plumber - If you are unable to diagnose the issue after following these steps, contact a licenced electrician or plumber for repair assistance.

Checking Power Supply

Once you’ve identified a loss of hot water, the first troubleshooting step is to check whether the electric water heater is getting power. Here’s how to do it safely:

  1. Locate the circuit breaker connected to the water heater in your main electrical panel. Check that it’s switched to the “On” position.
  2. Also check for any blown fuses in the fuse box that could cut power to the unit. Replace any blown fuses.
  3. Ensure the water heater’s external power switch is set to "On". Older units may not have an external switch.
  4. Use a non-contact voltage tester near the top heating element to confirm power is reaching the upper thermostat and heating element.
  5. If you don’t get a voltage reading, it’s time to say 'because I could use professional help’ and contact a licenced electrician.

Examining fundamental power connections can uncover simple fixes for cold water issues. Leave electrical repairs to the professionals for safety’s sake, unless you’re a qualified electrician.

Inspecting Heating Elements

Inspecting the heating elements is a key step in diagnosing electric water heater problems. Here’s how to do it safely and effectively:

  1. Turn off power to the water heater at the circuit breaker before servicing.
  2. Drain the tank of water by attaching a hose to the drain valve and opening the release lever.
  3. Once drained, remove the access panel on the exterior of the tank to expose the upper and lower heating elements.
  4. Visually inspect each element for signs of heavy mineral deposits, corrosion or cracks/damage. Cracks indicate it’s time to replace.
  5. Use a multimeter to check the resistance of each element. Refer to the manufacturer’s specs, but they typically show continuity in the 10-30 Ohm range when good.
  6. If an element is heavily corroded or fails the resistance test, replacement is needed. Ensure the wattage and voltage match the original.
  7. Reinstall the access panel, refill the tank, restore power and verify hot water flow after completing repairs.

Taking the time to properly inspect heating elements by sight and with a multimeter test can help identify and resolve common electric water heater faults. Always exercise caution when servicing electrical equipment.

Testing Thermostat

Testing the thermostat is crucial in diagnosing problems with electric water heaters. Follow these steps:

  1. Check that the thermostat is set to 55°C. Adjust if needed.
  2. Turn off power and remove thermostat’s access panel.
  3. Use a multimeter to test for continuity between the two wires leading from the thermostat.
  4. If there is no continuity, the thermostat is likely faulty and requires replacement.
  5. Install a new thermostat with identical temperature range and electrical specs.
  6. Replace access panel, restore power and recheck hot water flow.

Verifying proper thermostat operation and replacing if faulty can resolve hot water issues. Always take safety precautions when testing electrical components.

Gas Water Heater Troubleshooting

Troubleshooting gas hot water systems involves inspecting some key components. Follow these steps for a gas water heater not producing hot water:

  1. Inspect Pilot Light - Locate the pilot light assembly on the gas valve. If the pilot is out, refer to lighting instructions on the heater and relight. Ensure any pilot shield is reliably removed once the pilot is lit.
  2. Check Gas Supply Valve - Verify the manual gas shutoff valve is fully open. Close, then reopen the valve to clear any debris if necessary.
  3. Test Thermocouple - Remove and visually inspect the thin thermocouple rod near the pilot. Replace if corroded. Use a multimeter to check it produces minimum 18mV closed circuit.
  4. Inspect Burners - Remove burner access panel and check for obstructed ports or debris. Use a stiff brush or compressed air to clean out any debris effectively.
  5. Test Thermostat - Verify it’s set to 60°C. Use a multimeter to check for continuity between wires. Replace if faulty.
  6. Check for Leaks - If you smell gas or use leak detector fluid around pipes and don’t see bubbles, call the gas company immediately.

Following these troubleshooting steps for gas systems can help resolve common pilot, burner and thermostat issues to restore hot water. Never hesitate to call professionals for potential gas leaks or malfunctions.

Inspecting Pilot Light

Inspecting the pilot light is a critical step when troubleshooting a gas water heater that fails to produce hot water. Here is a step-by-step guide to ensure water comes out hot as expected by checking the pilot:

  1. Locate the pilot light assembly on the base of the water heater near the main gas burner. It will have a small flame when lit.
  2. If the pilot light is out, refer to the lighting instructions on the heater and carefully relight it. Make sure any pilot shield is reliably removed once the pilot is lit.
  3. Visually inspect the pilot light flame. It should burn steady and blue. A weak or yellow flame indicates a blocked pilot orifice.
  4. If the flame is weak, clean the pilot assembly with compressed air or a wire brush and attempt to relight.
  5. Still no flame? The thermocouple may need replacement. This sensor shuts off gas flow if the pilot goes out.
  6. Inspect the pilot tubing as well for cracks or blockages that can disrupt gas flow.

Checking the pilot light and making any necessary repairs to ensure it’s better than before, burning strong and steady, again is essential to restoring hot water on a gas system. Seek professional assistance if you encounter doubts or difficulties.

Checking Gas Supply

Ensuring adequate gas supply is vital when troubleshooting a gas water heater. Follow these steps:

  1. Locate the manual gas shutoff valve connected to the inlet pipe on the water heater. Verify the valve is turned fully counter-clockwise to the open position.
  2. Next, check for any kinks or blockages in the gas supply line. Straighten or clear obstructions.
  3. If the pilot flame is weak, briefly switch the gas valve to "Off" then back "On" to clear debris.
  4. Check tank water pressure. If below 40 psi, the heater may be in low gas flow safety mode. Boost pressure.
  5. Still no gas? Try relighting the pilot. If it won’t stay lit, contact your gas utility to inspect supply and service.

Assessing the gas supply can restore hot water functionality. Call a professional immediately if you ever smell gas.

General Water Heater Maintenance

Preventative maintenance keeps your water heater operating safely and efficiently. Follow these annual maintenance tips:

Sediment buildup reduces efficiency. Drain 2-3 gallons from the tank’s drain valve. Open hot water taps to flush until water runs clear. Refill tank.

Replace if necessary. Keep area around valve clean.

Briefly lift and release the test lever to flush and verify smooth operation. Replace if faulty.

Annual maintenance keeps your system operating safely and can significantly extend the life of your water heater. Contact a plumber if you experience more than just the usual quirks with your system.

Replace if necessary. Keep area around valve clean.

Briefly lift and release the test lever to flush and verify smand Flushing Tank

Regularly draining and flushing ylly crucial if you have hard water.

  1. First, ensure the electric water heater’s power is off, then switch the gas control valve to "pilot" on a gas unit before commencing any work.
  2. First then, attach a garden hose to the drain valve near the bottom of the tank; this is all you need to start the draining process.
  3. Open the drain valve to effectively drain the tank, allowing 2-3 gallons of water to empty into a bucket or a suitable outside area.
  4. Close the drain valve once draining is complete.
  5. Turn on a hot water tap to ensure water comes through clearly while you flush sediment until it runs clear.
  6. Turn off the tap, refill the tank and restore power or gas supply.

Sediment buildup can lead to rumbling, popping noises and a loss of hot water. Annual draining and flushing removes mineral deposits and prolongs the life of your water heater. Contact a plumber if you have difficulty with the process.

Inspecting Drain Valve

Inspecting the drain valve on your water heater annually ensures it operates smoothly for maintenance and emergencies. Follow these steps:

  1. Locate the drain valve near the bottom of the water heater tank. It will have a handle or release lever.
  2. Check below the valve for any drips or leaks that could indicate a faulty valve requiring replacement.
  3. Place a bucket underneath to catch water.
  4. Briefly open and close the drain valve. It should open and close smoothly without sticking.
  5. Make sure it fully seals closed again to prevent leaking.
  6. Clean any sediment or mineral buildup from around the valve.

Regular drain valve inspection is key for maintenance or emergencies. Ignoring an inoperable valve can lead to larger leaks and complications, which is why prompt plumber attention is advised.

Checking Pressure Relief Valve

The pressure relief valve is an important safety component on all water heaters. This valve helps prevent dangerous pressure buildup by opening and releasing excess heat and pressure if the tank exceeds safe limits. Checking it annually ensures it works properly when needed.

Follow these steps to test the pressure relief valve:

  1. Locate the pressure relief valve near the top of the water heater tank. It will have a lever arm with a test lever or tab on it.
  2. Place a bucket underneath the valve to catch any released water.
  3. Briefly lift up and release the test lever. This should release a small flow of water into the bucket.
  4. Allow the valve to snap shut again when released. It should move freely and not stick.
  5. If little or no water is released, or the valve fails to close fully, the valve may be mineral-encrusted and require replacement by a plumber.

Testing the pressure relief valve ensures its ability to release excess tank pressure, maintaining safety. This provides an essential safety measure for proper water heater operation.

The pressure relief valve is an important safety component on all water heaters. Checking it annually ensures it works properly whenr.

  • Briefly lift up and release the test lever. This should release a small flow of water into the bucket.
  • Allow the valve to snap shut again when released. It should move freely and not stick.
  • When to Call a Professional

    While many hot water issues caned in this guide, there are some situations where it’s best to call in a professional plumber for assistance:

    • You smell gas or detect leaks - This signals potentially serious hazards requiring immediate professional help. Don’t hesitate to call the gas company or licenced plumber.
    • The pilot light repeatedly goes out - If you can’t get the pilot light to stay lit despite cleaning and replacing components, professional diagnosis is needed.
    • Electrical issues are suspected - Don’t risk prolonged electrical downtime by attempting repairs yourself; enlist the services of a licenced electrician. Call a professional if unsure.
    • Pressure and temperature relief valves need replacement - These valves are crucial safety components that should be replaced by qualified plumbers.
    • Sediment flush fails to restore hot water - Heavy mineral buildup may require a full professional flush to remove all sediment from the tank.
    • The exact problem cannot be determined - If you are unable to isolate the issue through methodical troubleshooting, call for professional assistance.

    Leichhardt Plumbing’s experienced licensed plumbers are available round the clock to tackle persistent hot water issues. Give us a call at 1300 349 338 or email [email protected] to schedule service. We can quickly diagnose the issue and get your hot water flowing again.


    A reliable hot water system is key to everyday comfort and convenience. This guide’s detailed checklist can help solve frequent hot water issues, letting you enjoy warm showers as expected.

    A detailed inspection of heating elements, thermostats, pilot lights, and gas valves, complemented by tank flushing, can reinstate hot water. Annual maintenance, including flushing and anode rod replacement, enhances system longevity and performance.

    If cold water troubles persist, reach out to Leichhardt Plumbing. Our proficient, licensed plumbers are available to service the Sydney area. Dial 1300 349 338 or email [email protected] for assistance.

    Reach out to us for prompt diagnosis and expert repair of your hot water heater, ensuring hot water is swiftly restored in your home.

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