Silence the Thunder! Step-by-Step Guide to Eliminate Water Heater Knocking

Water heaters are essential appliances in our homes, providing us with hot water for showers, baths, and various household tasks. However, when a water heater starts knocking, it can be a nuisance and a sign of underlying issues. In this blog post, we will delve into the causes of water heater knocking and provide step-by-step instructions on how to fix it.

Causes of Water Heater Knocking

Water heater knocking is typically caused by one of the following reasons:

• Sediment Buildup: Minerals and sediment can accumulate at the bottom of the water heater tank, creating knocking sounds as the water flows through.
• Loose Heating Element: The heating element is responsible for heating the water in the tank. If it becomes loose, it can rattle against the tank walls, causing knocking.
• Faulty Pressure Relief Valve: The pressure relief valve releases excess water pressure from the tank. A faulty valve may not open properly, leading to pressure buildup and knocking.
• Air Pockets: Air pockets can form in the water heater tank, causing water to bubble and create knocking sounds.
• Water Hammer: When a water valve is suddenly closed, it can create pressure surges in the pipes, which can cause knocking in the water heater.

How to Fix Water Heater Knocking

1. Flush the Water Heater Tank

Sediment buildup is a common cause of water heater knocking. To flush the tank and remove sediment:

• Turn off the water supply to the water heater.
• Attach a garden hose to the drain valve at the bottom of the tank.
• Open the drain valve and allow the water to flow out until it runs clear.
• Close the drain valve and turn on the water supply.

2. Check the Heating Element

A loose heating element can cause knocking. To check it:

• Turn off the power to the water heater.
• Remove the access panel on the side or top of the water heater.
• Locate the heating element and check if it is loose.
• If it is loose, tighten it using a wrench.

3. Replace the Pressure Relief Valve

A faulty pressure relief valve can cause knocking. To replace it:

• Turn off the water supply to the water heater.
• Close the cold water inlet valve.
• Open a hot water faucet to release pressure.
• Unscrew the old pressure relief valve and install the new one.
• Open the cold water inlet valve and turn on the water heater.

4. Remove Air Pockets

Air pockets can cause knocking. To remove them:

• Turn off the water supply to the water heater.
• Open a hot water faucet to release pressure.
• Close the hot water faucet.
• Open the water supply to the water heater.

5. Install Water Hammer Arrestors

Water hammer can cause knocking. To install water hammer arrestors:

• Turn off the water supply to the water heater.
• Install water hammer arrestors on the hot and cold water pipes near the water heater.
• Turn on the water supply to the water heater.

Troubleshooting Water Heater Knocking

If the above steps do not resolve the knocking, try the following troubleshooting tips:

• Check the water heater thermostat: A high thermostat setting can cause excessive heat buildup and knocking.
• Inspect the anode rod: The anode rod protects the water heater tank from corrosion. If it is worn out, it can cause knocking.
• Call a plumber: If you are unable to fix the knocking yourself, contact a qualified plumber for assistance.

Final Thoughts

Water heater knocking can be a frustrating issue, but it can be resolved by addressing its underlying causes. By following the steps outlined in this guide, you can diagnose and fix the problem effectively. Remember, if you encounter any difficulties or safety concerns, do not hesitate to seek professional help.

What You Need to Know

Q: Why does my water heater make a knocking sound when I turn on the hot water?

A: Knocking sounds can be caused by sediment buildup, a loose heating element, or a faulty pressure relief valve.

Q: How often should I flush my water heater tank?

A: It is recommended to flush the water heater tank every 6-12 months to prevent sediment buildup.

Q: Can I replace the heating element myself?

A: Replacing the heating element requires electrical knowledge and should only be attempted by experienced DIYers. It is generally recommended to call a plumber for this task.