How to Flush a Tankless Water Heater

flush water heater sediment-a-tankless-water-heater-">How to Flush a Tankless Water Heater

Introduction

Tankless water heaters are an excellent choice for efficiency and convenience, providing hot water on demand without the need for a storage tank. However, like traditional water heaters, they are not immune to issues caused by hard water and mineral buildup. Over time, scale can form inside the heat exchanger, reducing efficiency and potentially damaging the system. Flushing your tankless water heater is a critical maintenance step to keep it running smoothly. In this guide, we’ll walk you through why it’s necessary, how often to do it, and step-by-step instructions to flush your tankless water heater.

Why Flushing is Essential for Tankless Water Heaters

Hard water deposits minerals such as calcium and magnesium inside your water heater’s heat exchanger. This buildup:

Reduces efficiency: Scale acts as an insulating barrier, making it harder to heat water.
Increases energy costs: Your unit uses more energy to maintain water temperature.
Shortens lifespan: Excessive scale can damage the heat exchanger, leading to costly repairs or replacements.

How Often Should You Flush a Tankless Water Heater?

The flushing frequency depends on factors such as water hardness and usage:

Hard Water Areas: Flush every 6 months if you live in an area with hard water.
Soft Water Areas: Flush every 12 months if a water softener is installed.
High Usage: Homes with heavy hot water usage should flush more frequently.

Use our Sediment Calculator to estimate how hard water affects your system and determine the ideal maintenance schedule.

What You’ll Need

Before you start, gather the following tools and supplies:

Submersible pump: Helps circulate the cleaning solution through the system.
Bucket: To hold the cleaning solution.
Vinegar or descaling solution: Removes scale effectively.
Hose set: Connects to the unit’s service ports.
Adjustable wrench: For opening and closing connections.
Safety gloves and goggles: Protect yourself during the process.

Step-by-Step Guide to Flushing Your Tankless Water Heater

Follow these steps to safely flush your tankless water heater:

1. Turn Off the Power and Water Supply

Switch off the water heater’s power source (electricity or gas).
Close the cold water inlet and hot water outlet valves to isolate the unit from your home’s plumbing.

2. Connect the Hoses

Attach the hoses to the service ports of your tankless water heater. These ports are typically located at the bottom of the unit.
Ensure the connections are secure to prevent leaks.

3. Prepare the Cleaning Solution

Fill a bucket with 4 gallons of white vinegar or a commercial descaling solution.
Place the submersible pump in the bucket and attach the hose to it.

4. Circulate the Solution

Open the service valves on the unit.
Turn on the pump to circulate the cleaning solution through the system.
Let the solution run for 45 minutes to 1 hour to dissolve scale deposits.

5. Flush with Clean Water

Turn off the pump and dispose of the used solution safely.
Refill the bucket with clean water and circulate it through the system for 5-10 minutes to rinse out any remaining descaling solution.

6. Reconnect and Restart

Close the service valves and disconnect the hoses.
Open the cold water inlet and hot water outlet valves.
Turn the power back on and test your unit for proper operation.

Additional Tips for Maintaining Your Tankless Water Heater

Install a Water Softener:
- Reduces the mineral content in water, minimizing scale buildup.
Use a Sediment Filter:
- Prevents debris and particles from entering the system.
Schedule Annual Inspections:
- A professional can check for issues and ensure optimal performance.

What Happens If You Don’t Flush Your Unit?

Neglecting to flush your tankless water heater can lead to:

Reduced efficiency: Your unit may struggle to heat water effectively.
Increased energy bills: More energy is required to overcome scale buildup.
Costly repairs: Heat exchanger damage from scale can require expensive fixes.
Premature replacement: A neglected system may need replacing years earlier than expected.

Conclusion: Keep Your Tankless Water Heater Running Smoothly

Flushing your tankless water heater is a simple yet essential task that ensures efficiency, lowers energy costs, and extends the life of your system. With regular maintenance, you can enjoy reliable hot water and avoid costly repairs. Not sure how much scale is building up in your water heater? Use our Sediment Calculator to find out and get personalized recommendations for your system.