How to Drain a Tankless Water Heater: Step-by-Step Guide for Maintenance

raameen irfan • Nov 02, 2023

Tankless water heaters, known for their efficiency and continuous hot water supply, require regular maintenance to ensure they function optimally. One essential maintenance task for a tankless water heater is draining it to remove sediment buildup, ensuring it operates efficiently and prolongs its lifespan. Thus, this comprehensive guide will walk you through the step-by-step process of draining a tankless water heater, helping you maintain it effectively.


Understanding the Importance of Draining a Tankless Water Heater

Water heaters without tanks function differently from conventional water heaters in that they heat water as it passes through the unit instead of holding hot water in reserve. However, the system's functionality may be impacted over time by the accumulation of minerals, trash, and silt. Moreover, draining the tankless water heater helps flush out these sediments, preventing potential issues like reduced water flow, decreased efficiency, and even component damage.


Safety Precautions Before Draining

Before you start the draining process, it's crucial to ensure safety. Follow these precautions:

  • Turn Off Power: Switch off the power supply to the water heater. For electric units, disconnect the power at the breaker. For gas units, switch off the gas supply.
  • Allow Cooling: To prevent burns from hot water, let the water heater cool for at least an hour before starting the draining operation.


Step-by-Step Guide to Drain a Tankless Water Heater


Step 1: Gather Necessary Tools and Materials

To effectively drain a tankless water heater, gather the following tools and materials:

  • Garden hose
  • Screwdriver
  • Bucket or drainage area
  • Vinegar or a descaling solution (optional)

Step 2: Locate and Access the Service Valves

  • Locate the service valves on the tankless water heater. There are typically inlet and outlet valves used for maintenance.
  • Shut off both the hot and cold water supply valves. These are usually located near the water heater. Turn off the isolation valves, ensuring no water enters the unit during the draining process.

Step 3: Connect the Garden Hose

  • Connect one end of the garden hose to the drain valve on the tankless water heater. Ensure it's securely attached.



Step 4: Position the Other End of the Garden Hose

  • Position the other end of the garden hose to an appropriate drainage area, such as a floor drain, utility sink, or outdoor location.

Step 5: Open the Drain Valve

  • Open the drain valve on the tankless water heater. This allows the water to flow out through the garden hose into the drainage area.
  • Also, keep the hot water faucet open at a nearby sink to help with the draining process and release pressure.


Step 6: Flush and Drain the Tankless Water Heater

  • Let the water heater's water run out completely. This could require some time, depending on the sediment buildup.  Be patient and ensure the water drains entirely.


Step 7: Optional Step - Descale the Water Heater (If Required)

  • If there is significant mineral buildup, you might consider descaling the unit. This involves running a descaling solution or vinegar through the system to break down mineral deposits. Follow the manufacturer's instructions for this process.



Step 8: Close the Drain Valve

  • Once the water is fully drained, close the drain valve tightly to prevent leaks.

Step 9: Reopen the Service Valves

  • Turn on the hot and cold water supply valves that were previously closed to allow water to flow back into the unit.



Step 10: Check for Leaks

  • Check the connections and the drain valve to ensure there are no leaks.


Step 11: Restore Power Supply

  • Turn the power supply back on for the tankless water heater. For gas units, relight the pilot according to the manufacturer's instructions.

Maintenance Tips and Frequency

  • Regular Draining: It's recommended to drain a tankless water heater at least once a year to prevent sediment buildup.
  • Consult Manufacturer's Manual: Always refer to the manufacturer's manual for specific instructions regarding draining and maintenance of your unit.
  • Consider Professional Service: If you're uncomfortable or unsure about the process, consider hiring a professional for maintenance.

Ensuring Longevity

For your tankless water heater to last longer and function well, regular maintenance is necessary, which includes draining the unit. You may efficiently empty your tankless water heater and contribute to its continued operation by following these detailed instructions. Never forget that safety comes first. Therefore, take all necessary safety precautions, and for detailed instructions, see your manufacturer's manual. For many years to come, your tankless water heater will give you a consistent and effective supply of hot water with regular maintenance.

Specialized Maintenance Services

Are you looking to enhance the efficiency and longevity of your tankless water heater? At Sunshine Plumbers, we understand the importance of regular maintenance to keep your tankless water heater in top shape. Moreover, our experienced technicians specialize in providing comprehensive maintenance services, including the vital task of draining tankless water heaters. In addition, with our expertise, we ensure that your system operates at its best, preventing sediment buildup and potential issues. Thus, trust Sunshine Plumbers for meticulous and professional care, allowing you to enjoy continuous hot water without the worry of reduced efficiency.


Superior Maintenance Experience

Experience the difference with Sunshine Plumbers! Our commitment to ensuring your tankless water heater functions optimally sets us apart. Furthermore, from locating service valves to flushing and draining the system, our skilled team follows a meticulous step-by-step process to maintain your tankless water heater. We value your safety and the smooth operation of your unit. Whether it's a routine maintenance task or handling mineral buildup, our technicians go the extra mile to provide you with quality service. Hence, contact Sunshine Plumbers today for reliable, professional care for your tankless water heater, and enjoy long-lasting, efficient hot water solutions.

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