How To Clean A Navien 150 Tankless Water Heater – Restore Flow &

ByDavid Clark

Is your morning shower starting to feel a little… lukewarm? Maybe you’ve noticed the water pressure isn’t what it used to be, or it takes forever for the kitchen sink to get hot. These are classic signs that your hard-working Navien tankless water heater is calling out for a little TLC.

I know what you might be thinking—another complicated home maintenance task. But don’t worry. We promise this is a job you can absolutely tackle yourself. Think of us as the friendly HVACR tech on your shoulder, guiding you through the process safely and effectively.

This comprehensive guide will show you exactly how to clean a navien 150 tankless water heater. We’ll cover the tools you’ll need, provide a step-by-step walkthrough, and share some pro tips to help you restore your unit’s performance, boost its efficiency, and extend its lifespan for years to come.

Why Cleaning Your Navien 150 is Non-Negotiable

Before we roll up our sleeves, let’s talk about why this annual maintenance is so critical. A tankless water heater works by flash-heating water as it passes through a complex component called a heat exchanger. Over time, minerals in your water—like calcium and magnesium—build up inside this exchanger, a process known as scaling.

This mineral buildup is the root cause of most performance issues. The benefits of how to clean a navien 150 tankless water heater go far beyond just getting hotter water. Regular descaling:

  • Restores Efficiency: Scale acts like an insulator, forcing your heater to work harder and use more energy to heat the water. Cleaning it away can significantly lower your utility bills.
  • Prevents Breakdowns: Left unchecked, scale can cause overheating, leading to sensor failures and costly repairs. It’s one of the most common problems we see in the field.
  • Improves Water Pressure: As mineral deposits narrow the passages within the heat exchanger, water flow is restricted. A good cleaning opens everything back up.
  • Extends Lifespan: A clean unit is a happy unit. Annual descaling is the single best thing you can do to ensure your Navien heater lasts for its full 15-20 year expected lifespan.
  • Maintains Your Warranty: Many manufacturer warranties require proof of regular maintenance. Keeping a record of your annual cleaning protects your investment.

Gathering Your Tools & Materials: The Pro’s Checklist

Having everything ready before you start makes the process smooth and stress-free. You don’t need a truck full of specialized equipment—just a few key items. Here’s your shopping and gathering list.

This is a great opportunity to practice sustainable how to clean a navien 150 tankless water heater maintenance by choosing reusable or biodegradable options where possible.

  1. Submersible Pump: A small 1/6 HP utility pump is perfect for circulating the cleaning solution.
  2. 5-Gallon Bucket: This will hold your descaling solution.
  3. Washing Machine Hoses (2): You’ll need two hoses with standard female hose connections on both ends. Make sure they are long enough to reach from your heater to the bucket on the floor.
  4. Descaling Solution: You can purchase a commercial descaler specifically designed for potable water systems, or you can use a simple solution of diluted white vinegar. We’ll cover that next.
  5. Channel-lock Pliers or an Adjustable Wrench: For tightening and loosening hose connections.
  6. Old Towels or Rags: To catch any minor drips and spills.

Choosing Your Descaling Solution: Vinegar vs. Commercial Products

You have two main options for your cleaning solution, and both work well.

Food-Grade White Vinegar: This is the most common, eco-friendly how to clean a navien 150 tankless water heater solution. It’s inexpensive, readily available, and non-toxic. The standard mixture is one gallon of vinegar mixed with one gallon of water in your bucket.

Commercial Descaler: Products like Flow-Aide or Hay-Maker are specifically formulated to dissolve mineral scale quickly. They often work faster than vinegar but can be more expensive. Always follow the manufacturer’s dilution instructions precisely.

The Complete Guide on How to Clean a Navien 150 Tankless Water Heater

Alright, you’ve got your tools and you’re ready to go. We’ve broken down this how to clean a navien 150 tankless water heater guide into simple, manageable steps. Just follow along, and you’ll be done in about an hour.

Step 1: Safety First – Prepping Your Workspace

Before you touch anything on the unit, we need to make sure it’s safe to work on. This is the most important step.

  1. Turn Off the Power: Go to your home’s electrical panel and flip the breaker that powers your Navien water heater. If it’s a plug-in model, simply unplug it from the wall.
  2. Shut Off the Gas: Locate the gas valve on the line leading to the heater (it usually has a yellow or red handle). Turn the handle a quarter-turn so it is perpendicular (at a 90-degree angle) to the pipe.
  3. Close the Water Valves: Your Navien unit has three valves on the bottom: a blue handle (cold water inlet), a red handle (hot water outlet), and a main water valve for the house line. Close all three by turning the handles perpendicular to the pipes.
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Step 2: Isolating the Unit and Connecting Hoses

Now we’ll connect our cleaning kit. The Navien isolation valves make this part easy.

  1. Relieve Pressure: Locate the small T-shaped pressure relief handles on the red and blue valves. Flip them open to release any trapped pressure. A little water might spurt out, so have a towel ready.
  2. Connect the Hoses: Unscrew the purge port caps from the red and blue valves.
    • Connect one hose to the cold water (blue) valve. Place the other end of this hose into your 5-gallon bucket.
    • Connect the second hose to the hot water (red) valve. Attach the other end of this hose to the outlet of your submersible pump.
  3. Prepare the Pump & Solution: Place the submersible pump inside the bucket. Mix your descaling solution (e.g., 1 gallon of vinegar and 1 gallon of water) and pour it into the bucket, making sure the pump is fully submerged.

Step 3: The Descaling Process – Circulating the Solution

This is where the magic happens. We’re going to create a closed loop to circulate the descaler through the heat exchanger.

  1. Open the Isolation Valves: Open the T-shaped handles on both the red and blue service valves. They should now be parallel with the pipes. This is crucial. This isolates the heater from your home’s plumbing and directs the flow through your hoses.
  2. Start the Pump: Plug in your submersible pump. You should see the solution get sucked up through the hose connected to the hot valve, circulate through the heater, and return to the bucket via the hose on the cold valve.
  3. Let it Run: Allow the pump to circulate the solution for at least 45-60 minutes. You might see the solution get cloudy or change color as it dissolves the mineral scale. This is a good sign!

Step 4: Flushing the System Clean

Once the descaling is done, we need to flush out the solution and any loosened debris.

  1. Turn Off the Pump: Unplug your submersible pump.
  2. Drain the Descaler: Remove the hose from the pump and drain the remaining solution from the heater into the bucket.
  3. Flush the Cold Side: Close the red (hot) isolation valve. Keep the blue (cold) valve open. Disconnect the hose from the cold valve and point it into the bucket or a nearby drain. Briefly open the main cold water inlet valve to the heater for about 30 seconds to flush fresh water through. Close the main valve again.
  4. Flush the Hot Side: Now, close the blue (cold) isolation valve and open the red (hot) one. Do the same thing: flush fresh water through the hot side for 30 seconds to clear any remaining debris.

Step 5: Restoring Service and Checking Your Work

We’re on the home stretch! It’s time to put everything back to normal.

  1. Disconnect Hoses: Remove both of your cleaning hoses and securely screw the purge port caps back on.
  2. Clean the Inlet Filter: This is a key pro tip! On the bottom of the cold water inlet pipe, there’s a small screen filter. Unscrew it, rinse it thoroughly under a faucet to remove any debris, and screw it back in. This prevents clogs.
  3. Restore Water Flow: Ensure both T-shaped pressure relief handles are closed. Then, slowly open the main cold water valve, the blue valve, and the red valve. Listen for the sound of water refilling the unit.
  4. Restore Power and Gas: Turn the gas handle back to the parallel (on) position. Then, go to your breaker panel and flip the power back on to the unit.
  5. Test: Turn on a hot water tap in your home. It might sputter for a moment as air escapes the line. Let it run until it’s clear and hot. Check the unit for any leaks.
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Pro Tips & Best Practices for a Flawless Flush

As a technician, I’ve picked up a few tricks over the years. This how to clean a navien 150 tankless water heater care guide wouldn’t be complete without them.

  • Annual Reminder: Set a calendar reminder on your phone for the same time next year. Consistency is key to preventing major buildup.
  • Hard Water Areas: If you know you have very hard water, consider descaling every 6-9 months instead of annually.
  • Never Run the Unit Dry: Double-check that water is fully restored to the unit before you turn the power back on. Running the heating element dry can damage it instantly.
  • Check for Leaks: After you’re done, take a dry paper towel and wipe around each connection you touched. This is the easiest way to spot a tiny drip.

Common Problems & When to Call a Professional

This DIY process covers 95% of maintenance needs. However, there are times when it’s best to call in a licensed professional. Here are some common problems with how to clean a navien 150 tankless water heater that signal you need an expert.

  • Persistent Error Codes: If your Navien is displaying an error code that doesn’t clear after the cleaning, it indicates a deeper issue with a sensor or component.
  • Leaks from the Unit Casing: If you see water dripping from anywhere other than the connections you’ve worked on, shut off the water and call for service immediately.
  • No Hot Water After Cleaning: If you’ve followed all the steps and still can’t get hot water, there might be an ignition or gas flow problem that requires a trained technician.
  • If You’re Uncomfortable: There’s no shame in it! If you feel overwhelmed by the process or aren’t comfortable working with gas and electricity, calling a pro is the safest bet.

Frequently Asked Questions About Cleaning a Navien 150

How often should I clean my Navien 150?

For most homes with average water hardness, cleaning your Navien 150 once a year is the recommended interval. If your area has particularly hard water, you may benefit from descaling every six to nine months.

Can I use regular household vinegar to descale my tankless water heater?

Yes, you can. A solution of 50% water and 50% plain white vinegar is a safe, effective, and non-toxic way to descale your unit. It’s one of the most popular eco-friendly methods.

What happens if I don’t clean my Navien tankless water heater?

Neglecting this maintenance will lead to a buildup of mineral scale. This causes reduced efficiency (higher bills), lower water pressure, fluctuating water temperatures, and can ultimately lead to premature component failure and a shorter lifespan for the unit.

Is this cleaning process eco-friendly?

Absolutely. By using a biodegradable solution like white vinegar, you’re performing a sustainable how to clean a navien 150 tankless water heater flush. The process also restores the unit’s energy efficiency, reducing its overall carbon footprint. Properly disposing of the used solution according to local guidelines completes the eco-friendly cycle.

Your Key to Long-Lasting Hot Water

Congratulations! You’ve just completed one of the most important maintenance tasks for your home’s plumbing system. By taking an hour each year to follow this guide, you’re not just ensuring a steady supply of hot water; you’re protecting your investment, saving money on energy bills, and preventing future headaches.

Regular maintenance is the cornerstone of a healthy, efficient home. Keep up the great work, and enjoy that perfectly hot, high-pressure shower—you’ve earned it! Stay safe and stay comfortable!

David Clark
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