Gas Hot Water Not Working? Common Problems and Expert Solutions

March 10, 2025

Hot water

At Liquid Force Plumbing, we understand how frustrating it can be when your gas hot water system fails. Whether you’re experiencing no hot water, fluctuating temperatures, or a pilot light that won’t stay lit, we’re here to help. In this guide, we cover the most common issues with gas hot water systems and provide step-by-step solutions to get your hot water running efficiently again.

Common Gas Hot Water Problems and Solutions

1. No Hot Water

Possible Causes:

Gas supply issues
Faulty pilot light or ignition system
Thermocouple failure
Malfunctioning gas control valve

Solutions:

Check the Gas Supply: Ensure the main gas valve is fully open and that other gas appliances in your home are functioning.
Inspect the Pilot Light: If the pilot light is out, follow the manufacturer’s instructions to relight it. If it won’t stay lit, the thermocouple may need replacement.
Test the Thermocouple: If the thermocouple is faulty, it won’t detect the pilot flame, causing the gas supply to shut off. A professional Perth plumber can replace it.
Replace the Gas Control Valve: If other components are functioning but there’s still no hot water, the gas control valve might be defective and should be replaced by a licensed technician.

2. Water Temperature Fluctuations

Possible Causes:

Sediment buildup in the tank
Faulty thermostat
Gas burner issues

Solutions:

Flush the Tank: Over time, sediment accumulates in the bottom of the tank, affecting efficiency. Flush the tank by draining it completely and refilling it.
Adjust or Replace the Thermostat: If the temperature setting is too low, increase it slightly. If the problem persists, the thermostat may need replacement.
Clean the Burner Assembly: A clogged or dirty burner can cause inconsistent heating. Turn off the gas, remove the burner, and clean it with a brush and compressed air.

3. Pilot Light Won’t Stay Lit

Possible Causes:

Dirty or misaligned thermocouple
Drafts or ventilation issues
Defective gas valve

Solutions:

Clean the Thermocouple: Use a fine sandpaper or steel wool to remove carbon buildup from the thermocouple.
Check for Drafts: Ensure there are no strong air currents blowing out the pilot light. Adjusting ventilation or sealing gaps may help.
Replace the Gas Valve: If cleaning and realignment don’t fix the issue, the gas valve may be faulty and require professional replacement.

4. Strange Noises from the Heater

Possible Causes:

Sediment buildup
Expansion and contraction of pipes

Solutions:

Flush the Tank: As mentioned earlier, sediment buildup can cause rumbling or popping sounds. Draining the tank removes these deposits.
Inspect Pipes for Expansion Issues: If pipes are making knocking noises, consider adding insulation or installing expansion loops.

5. Gas Smell Around the Heater

Possible Causes:

Gas leak from fittings or supply line

Solutions:

Shut Off the Gas Immediately: If you smell gas, turn off the gas supply at the main valve and ventilate the area.
Check for Leaks: Apply soapy water to the gas connections and look for bubbles, which indicate a leak.
Call a Professional: If you detect a gas leak, do not attempt repairs yourself—contact a licensed gas fitter immediately.

Preventative Maintenance Tips

Regular maintenance can extend the lifespan of your gas hot water system and prevent unexpected failures:

Flush the tank annually to remove sediment.
Check and clean the burner assembly every six months.
Test the pressure relief valve to ensure proper function.
Inspect for gas leaks periodically for safety.

When to Call a Professional

While some troubleshooting steps can be done yourself, certain issues—such as gas leaks, valve replacements, and extensive system repairs—should always be handled by a licensed plumber. If you’re unsure about your gas hot water system, Liquid Force Plumbing is here to help.