Maintaining the efficiency and longevity of your tankless water heater requires regular flushing. Unlike traditional water heaters with large tanks that collect sediment, tankless models heat water on demand. As a result, mineral deposits can accumulate within the unit’s internal components, potentially impairing its performance. Flushing helps remove these deposits, ensuring optimal operation and extending the life of your water heater.
The frequency of flushing depends on water hardness and usage patterns. In areas with hard water, sediment buildup occurs more rapidly. Heavy water consumption also increases the need for flushing. As a general guideline, it’s recommended to flush your tankless water heater annually or whenever a drop in water pressure or temperature is noticed. Additionally, if you have recently installed a new water softener, flushing is advisable to remove any residual sediment that may have entered the water heater.
Flushing a tankless water heater is a straightforward process that can be easily completed by most homeowners. By understanding the importance of flushing and following proper procedures, you can maintain the efficiency and reliability of your water heater for many years to come. The steps involved in flushing a tankless water heater are as follows:
Inspecting the Water Heater
Before flushing your tankless water heater, it’s crucial to inspect it thoroughly to ensure its overall condition. Here are a few essential steps to follow during the inspection:
1. Check the Power Source
| Electrical Water Heaters | Gas Water Heaters |
|---|---|
| Inspect the electrical wiring and connections for any loose or damaged wires. | Check the gas line and connections for any leaks or damage. Ensure the gas valve is fully open. |
If you notice any irregularities with the power source, it’s advisable to consult a qualified electrician or gas technician to address the issue before proceeding with the flushing process.
2. Examine the Exterior
Inspect the exterior of the water heater for any visible signs of damage, such as dents, cracks, or rust. Look for any leaks or water dripping from the unit. If you notice any concerning signs, it’s essential to investigate further and resolve any underlying issues before flushing.
3. Check the Inlet and Outlet Pipes
Inspect the inlet and outlet pipes connected to the water heater. Ensure there are no obstructions, kinks, or leaks. Check the condition of the hoses or pipes and replace any worn or damaged ones. Tighten any loose connections to prevent potential water leaks.
4. Verify the Pressure Relief Valve
Locate the pressure relief valve, typically a small red or blue lever or knob on the side of the water heater. Lift and release the lever several times to ensure it’s functioning correctly and releasing any excess pressure buildup.
Shutting Off the Water Supply
Before beginning any maintenance or flushing procedures on your tankless water heater, it is essential to shut off the water supply. Follow these steps to safely isolate your water heater from the mains:
1. Locate the Water Shut-Off Valves
First, identify the two water shut-off valves connected to your tankless water heater. These valves are typically located near the unit itself or on the water supply lines leading into the heater. Valves may be labeled as “hot” and “cold” or may have handles colored red (hot) and blue (cold).
2. Turn Off the Water Supply Valves
Once you have found the shut-off valves, proceed to close them completely. Turn both handles clockwise until they stop turning. If the valves are particularly difficult to turn, you may need to use a wrench for assistance. Avoid excessive force, as this can damage the valves.
Additional Tips:
– If your water shut-off valves are not working properly, they may need to be replaced. Contact a licensed plumber for assistance.
– If your water heater has a gas supply line, you will also need to shut off the gas supply before performing any maintenance or flushing procedures.
Locating the Flush Valve
The flush valve is typically located at the bottom of the tankless water heater. It may be covered by a small panel or cap. To locate the flush valve:
- Turn off the water supply to the water heater.
- Disconnect the power supply to the water heater.
- Remove the access panel or cap covering the flush valve.
In some cases, the flush valve may not be visible from the front of the water heater. You may need to remove a side panel or access the flush valve from the back of the water heater. Consult the manufacturer’s instructions for specific instructions on how to locate the flush valve for your particular model.
| Brand | Flush Valve Location |
|---|---|
| Rheem | Bottom of the water heater, behind a small panel. |
| Rinnai | Bottom of the water heater, accessible from the front. |
| Navien | Back of the water heater, behind a side panel. |
Flushing the Tankless Water Heater
1. Safety Precautions
Before starting, ensure your water heater is turned off at the main power source. Also, if the water heater has been recently in use, allow it to cool down to prevent burns.
2. Open the Hot Water Faucet
Open a hot water faucet furthest from the water heater to release pressure in the system.
3. Drain the Sediment
Locate the drain valve on the water heater and connect a garden hose to it. Open the drain valve and let the water run until it becomes clear, indicating that the sediment has been flushed out.
4. Flushing the System
Run vinegar or a descaling solution through the water heater to remove any remaining mineral deposits. Here’s a detailed step-by-step guide:
Materials:
| Item | Quantity |
|---|---|
| White vinegar or descaling solution | 1 gallon |
| Funnel | 1 |
| Bucket | 1 |
| Location | Potential Cause |
|---|---|
| Pipe connections | Loose or damaged connections |
| Drain valve | Failed or worn-out seals |
| Relief valve | Malfunctioning or blocked valve |
| Heat exchanger | Cracks or corrosion due to high temperatures or water quality |
| Expansion tank | Failed or ruptured diaphragm |
Reopening the Water Supply
Once you have successfully flushed the tankless water heater, it is time to reopen the water supply.
6. Turn on the Water Supply
Locate the main water shut-off valve, typically found near the water heater or under a sink. Slowly open the valve by turning it counterclockwise.
Wait a few minutes for the water to refill the system. Check for any leaks around the water heater or fixtures.
Once the system is refilled, turn on the individual faucets and showers to purge any remaining air or sediment from the lines.
Let the water run for a few minutes to ensure that hot water is being produced consistently.
Usage Tips for Tankless Water Heaters
- Avoid excessive flushing: Flushing your tankless water heater too often can remove scale buildup, which can actually improve efficiency.
- Consider a descaling solution: If you have hard water, consider using a descaling solution specifically designed for tankless water heaters.
- Monitor water pressure: Low water pressure can reduce the performance of your tankless water heater. If you experience low pressure, contact a licensed plumber to investigate.
- Regular maintenance: Schedule regular maintenance with a qualified technician to ensure optimal performance and longevity of your tankless water heater.
How To Flush Tankless Water Heater
Running Hot Water
Run the hot water from a faucet for 15-20 minutes. This will help to flush out any sediment or debris that may have built up in the unit.
If you have a multiple-faucet system, open each faucet one at a time and let the water run for a few minutes from each one. This will help to flush out any sediment or debris that may have built up in each faucet.
Once you have run the hot water for 15-20 minutes, check the water temperature. If the water is still not hot enough, repeat the process until the water reaches the desired temperature.
Tips for Running Hot Water
To prevent sediment and debris from building up in your tankless water heater, it is important to flush the unit regularly. You should also check the water temperature regularly and adjust the thermostat as needed. Additionally, you should inspect the unit for any leaks or damage on a regular basis.
Troubleshooting Common Issues
1. No Hot Water
First, check the power supply to the water heater. If the power is out, reset the circuit breaker or fuse. If the power is on, check the water pressure. Low water pressure can cause the water heater to shut off. Increase the water pressure by opening the main water valve.
2. Water Temperature is Too Low
If the water temperature is too low, adjust the temperature setting on the water heater. The temperature setting is usually located on the front of the water heater.
3. Water Temperature is Too High
If the water temperature is too high, adjust the temperature setting on the water heater. The temperature setting is usually located on the front of the water heater.
4. Water Heater is Making Noise
If the water heater is making noise, it could be a sign of a problem. The most common cause of noise in a water heater is sediment buildup. Sediment can cause the water heater to make a rumbling or banging noise.
5. Water Heater is Leaking
If the water heater is leaking, it is important to turn off the water supply and call a plumber. A leak can be caused by a number of things, including a cracked tank, a faulty valve, or a loose connection.
6. Water Heater is Not Turning On
If the water heater is not turning on, check the power supply to the water heater. If the power is out, reset the circuit breaker or fuse. If the power is on, check the water pressure. Low water pressure can cause the water heater to shut off.
7. Water Heater is Not Heating Evenly
If the water heater is not heating evenly, it could be a sign of a problem. The most common cause of uneven heating in a water heater is sediment buildup. Sediment can clog the water heater’s heating element, causing it to heat unevenly.
8. Gas Water Heater is Not Igniting
If a gas water heater is not igniting, it could be a sign of a problem. The most common causes of ignition failure in a gas water heater are a faulty igniter, a clogged gas line, or a problem with the gas valve.
| Possible Cause | Solution |
|---|---|
| Faulty igniter | Replace the igniter. |
| Clogged gas line | Clean the gas line. |
| Problem with the gas valve | Call a plumber. |
Professional Flushing Services
Hiring a professional plumbing service to flush your tankless water heater is highly recommended. They possess the expertise, tools, and experience to ensure a thorough and efficient cleaning process. Professional services typically include:
Comprehensive Inspection:
Before flushing, plumbers will inspect your heater for any potential issues or blockages. They’ll examine the inlet and outlet pipes, verifying that there are no obstacles hindering water flow.
Expert Cleaning:
Using specialized equipment, professionals flush the heat exchanger using a combination of water and chemical solutions. This process removes scale, sediment, and debris, restoring optimal heat transfer and preventing premature breakdowns.
Descaling and Dezincification:
Depending on the specific model and the water conditions in your area, plumbers may perform descaling (to remove calcium and magnesium buildup) or dezincification (to remove zinc corrosion) as part of the flushing process.
Preventive Maintenance:
Professional flushing services often include additional preventive maintenance tasks, such as checking anode rods (which protect against corrosion), replacing filters, and inspecting other components for proper functioning. These steps help extend the lifespan and efficiency of your tankless water heater.
Cost Considerations:
The cost of professional flushing services can vary depending on the complexity of the job, the location, and the reputation of the plumbing company. However, it’s generally a worthwhile investment that can save you money in the long run by preventing costly repairs and replacements.
Maintenance Tips for Optimal Performance
1. Regular Flushing
Flushing your tankless water heater annually is crucial to remove sediment buildup and maintain its efficiency. Here’s a detailed step-by-step guide:
- Turn off the water supply to the heater.
- Open the hot water faucets throughout your home to release pressure.
- Connect a garden hose to the flush valve on the heater.
- Open the flush valve and run water through the hose for about 30 minutes.
- Close the flush valve and the hot water faucets.
- Turn on the water supply to the heater.
2. Inspect the Anode Rod
The anode rod sacrificially corrodes to protect the tank from rust. Inspect it every year and replace it if it’s worn out.
3. Descale the Unit
Hard water can cause mineral buildup, which can reduce the heater’s efficiency. Descaling removes this buildup using a descaling solution.
4. Check Gas Pressure
Gas-powered tankless water heaters rely on a steady gas supply. Check the gas pressure annually to ensure it’s within the manufacturer’s specified range.
5. Monitor Temperature Settings
Adjust the temperature settings of the heater to your desired level and monitor them over time. If the temperature fluctuates or doesn’t reach the desired level, it may indicate a problem.
6. Clean the Burner
The burner is responsible for heating the water. Clean it regularly to ensure it’s functioning properly and free of debris.
7. Check for Leaks
Inspect the unit for leaks around connections and pipes. If you notice any leaks, call a qualified plumber for repairs.
8. Winterizing
In cold climates, it’s important to winterize the tankless water heater to prevent it from freezing and damage.
9. Troubleshooting Common Issues
Become familiar with common issues that can affect your tankless water heater and learn some troubleshooting tips to address them.
10. Professional Maintenance
For optimal performance and longevity, it’s recommended to schedule professional maintenance every 2-3 years, where a qualified plumber can perform a thorough inspection, cleaning, and any necessary repairs. Doing so can extend the lifespan of your tankless water heater and ensure its efficient operation.
How to Flush a Tankless Water Heater
Tankless water heaters are a great way to save energy and money, but they do require a bit of maintenance to keep them running properly. One important task is to flush the tankless water heater annually. This process helps to remove sediment and scale buildup that can reduce the efficiency of the heater and cause premature failure.
Flushing a tankless water heater is a relatively simple process, but it is important to follow the manufacturer’s instructions carefully. Here are the general steps involved:
- Turn off the water supply to the tankless water heater.
- Open a hot water faucet to release any remaining water pressure.
- Attach a garden hose to the flush valve on the tankless water heater.
- Open the flush valve and allow the water to run for 15-20 minutes.
- Close the flush valve and disconnect the garden hose.
- Turn on the cold water supply to the tankless water heater.
- Open a hot water faucet to check for hot water.
