Common Problems with Gas Water Heaters

Although Colorado’s climate has warmed significantly over the past 30 years, many homeowners still rely on their gas water heaters for a consistent hot water supply. If you own a gas water heater, learning to recognize some of the most common gas water heater problems will help protect your home. The experts at Sanders & Johnson Heating, Cooling, and Plumbing have some insight into the most common issues, causes, and how to address these gas water heater woes.

Key Takeaways:

Sanders & Johnson specialize in addressing some of the most common problems with gas water heaters that Colorado homeowners face.
It’s important to know what to do next if you encounter a problem with your gas water heater, and when to call a professional.
Use specific troubleshooting methods to identify and address gas water heater issues as early as possible.

What Is the Most Common Problem With a Gas Hot Water Heater We See?

While gas water heater issues vary based on factors like age and maintenance, the most common problems we see include a lack of hot water even though the water heater pilot light is on, thermocouple issues, insufficient hot water, short-cycling, and strange noises or gas odors.

1. Water Heater Pilot Light On But No Hot Water

If your gas water heater is not working but the pilot light is on, you’re left without hot water for cooking, cleaning, and bathing.

Common causes

If your pilot light is on but there’s no hot water, something is preventing the main burner from firing. Some common causes include:

A faulty thermocouple.
A defective gas control valve.
Excess sediment buildup inside the tank.
Thermostat issues.

How to troubleshoot?

Here’s how to troubleshoot your gas water heater when the pilot light is on, but there’s no hot water:

Make sure the gas supply to your house is on and that the main gas control valve to the water heater is fully open.
Inspect the flame sensor to make sure it’s firmly in place, and gently clean it with fine sandpaper if it appears dirty.
Turn your gas control valve off, wait several minutes, and turn it back on to try to relight the pilot light.
Confirm that the burner assembly is clean and free of obstructions that could impede gas supply.

2. Thermocouple Problems

A bad thermocouple can cause various problems with your water heater. If you experience gas water heater thermocouple issues, contact the skilled technicians at Sanders & Johnson for professional repairs.

Symptoms of a bad thermocouple

Look for these symptoms that indicate you may have a bad thermocouple:

The pilot light goes out immediately after you release the reset button, or it fails to stay lit.
Your gas water heater turns on initially, then shuts off quickly.
You’re having trouble getting the pilot light to light up and ignite at all.
There is visible soot or discoloration on the tip of the thermocouple.
You notice damaged wiring or bent, corroded, or cracked parts.

When to replace a water heater thermocouple?

Repairs can solve some thermocouple, but others mean this component should be replaced. If you experience the following problems, you should replace the thermocouple:

The pilot light won’t stay lit after cleaning and resetting.
The gas is on, but the flame won’t ignite at all, no matter what you try.
You experience these issues repeatedly, and your gas water heater is 10 years old or older.

3. Gas Water Heater Not Producing Enough Hot Water

A gas water heater not producing enough hot water is a common issue that often occurs when a component is broken or starts malfunctioning.

Common causes

Here are some common causes of a gas water heater not producing enough hot water:

The thermostat is faulty, or the temperature is set too low.
Minerals like magnesium and calcium have settled at the bottom of the tank, reducing its capacity.
The dip tube that directs cold water to the bottom of the tank is broken.
Your burner isn’t firing correctly due to pilot light or igniter issues.
The water heater’s anode rod is old or failing and needs replacement.
Pipes coming from the tank are not insulated properly, causing heat loss and insufficient hot water.

Troubleshooting steps

Follow these troubleshooting steps if your gas water heater stopped working and isn’t producing enough hot water:

Step one: Make sure the thermostat dial is set to at least 120 degrees or higher.
Step two: Confirm that the pilot light is lit and blue in color or reset it if it’s out.
Step three: Only bathe or shower when other appliances like the washing machine or dishwasher are not in use, as this could cause excess hot water usage.
Step four: Check to make sure the gas valve is open and there is gas going to the water heater.
Step five: Contact a professional to check other parts, like the anode rod, dip tube, and electrical components.

4. Water Heater Keeps Running or Cycling On and Off

If your gas water heater keeps running or keeps cycling on and off, there could be a major issue at play. This common problem also reduces the water heater’s performance and efficiency.

Common causes

Some of the most common causes of this issue include:

The thermostat is set too high, causing the water heater to shut off due to overheating.
Too much sediment is built up inside the tank, forcing the burner to work harder.
There is dust, lint, or other debris on the burner or air intake screen, causing the water heater to shut down.
The thermocouple or high-limit switch is tripping because the water is too hot.

What to do next?

Here’s what to do if your gas water heater keeps running or short-cycling:

Lower the thermostat to around 120 degrees.
Clean the air intake screen gently using a soft brush.
Make sure the vent pipe above the tank is free of obstructions.
Check the pilot light and gently clean the tube with a needle or fine sandpaper.

5. Strange Noises From Your Gas Water Heater

Strange noises from your gas water heater are certainly cause for concern. In some cases, these noises are a sign that it’s time to replace the water heater.

Common causes

These are some common causes of strange noises coming from your gas water heater:

Popping or rumbling is often caused by sediment buildup.
Hissing or sizzling noises may signal a leak or condensation on the burner.
Ticking or tapping sounds might be from loose components or expanding metal.
Screeching or whistling is often due to restricted water flow or high pressure.

What to do next?

Follow these tips if you notice strange noises from your gas water heater:

Perform a drain, flush, and refill to remove excess sediment.
Check and tighten any loose pipes and components if you hear a banging or knocking sound.
If you don’t know how to address the noise, contact an experienced plumber to troubleshoot and diagnose the issue.

6. Gas Smell, Leaks, or Visible Corrosion

The smell of gas, leaks, or visible corrosion are all signs of a serious problem. If you experience any of these issues, it’s important to know what to do next.

What to do next?

Do the following if you notice a gas smell, leak, or see corrosion on your gas water heater:

If you detect the odor of gas, turn off the gas supply, evacuate your home, and call a professional immediately.
Turn off the water supply and try to find the source if your water heater is leaking, then call a pro for help.
Visible corrosion is a major red flag of a serious underlying issue that requires professional attention.

When Should You Call a Professional for Gas Water Heater Issues?

While some issues may be repairable yourself, always call a professional if you smell the odor of gas or see a yellow pilot light. You should also call a professional if the water heater keeps making loud noises, is leaking, or is not working at all.

Contact Sanders & Johnson Today!

If you face any of these problems with your gas water heater, Sanders & Johnson Heating, Cooling, and Plumbing is available to help. Contact us to schedule your water heater service today at 720-358-1813!