Navien Tankless Water Heater With Recirculating Pump Installation

Let’s be honest: standing by the sink, shivering while you wait for the shower to warm up, is one of life’s little frustrations. You watch perfectly good water—and money—run straight down the drain. What if you could turn on the tap and get instant, endless hot water, every single time?

This isn’t a futuristic dream; it’s the reality offered by modern tankless water heaters. Specifically, a Navien unit with a built-in recirculating pump is a game-changer for home comfort and efficiency. It eliminates the wait and dramatically cuts down on water waste.

Imagine the convenience of immediate hot water for your morning coffee, the peace of mind knowing you’re conserving a precious resource, and the satisfaction of a lower water bill. That’s the transformation we’re talking about.

This comprehensive guide will walk you through everything you need to know about a successful navien tankless water heater with recirculating pump installation. We’ll cover the benefits, the essential planning steps, and the best practices to ensure you get it right, whether you’re a hands-on homeowner or vetting a professional for the job.

Why a Navien Tankless with Recirculation is a Smart Upgrade
Before we dive into the nuts and bolts, let’s clarify what makes this combination so powerful. A standard tankless water heater heats water on demand, which is already a huge leap in efficiency over a bulky tank that constantly reheats water. But you still have to wait for that hot water to travel from the heater to your faucet.
The recirculating pump solves that problem. It creates a loop, periodically or intelligently circulating a small amount of hot water through your pipes. This keeps the lines primed and ready, so the moment you turn on the tap, hot water is there. Here are the core benefits of navien tankless water heater with recirculating pump installation:
Instant Comfort: No more waiting. Hot water is available within seconds, transforming your daily routines.
Massive Water Savings: The average family can waste thousands of gallons of water per year waiting for it to heat up. Recirculation nearly eliminates this waste, making for a truly eco-friendly navien tankless water heater with recirculating pump installation.
Energy Efficiency: Navien’s condensing technology is incredibly efficient (often over 95%). While the pump uses a small amount of electricity, the on-demand heating and water savings lead to significant overall energy conservation compared to tank models.
Space-Saving Design: These compact, wall-mounted units free up valuable floor space where a traditional tank heater used to sit.
Endless Hot Water: Unlike a tank that can run out, a properly sized tankless unit will provide continuous hot water for as long as you need it.

Before You Begin: Essential Pre-Installation Planning
Proper planning is 90% of the battle. Rushing into an installation without doing your homework is a recipe for headaches and poor performance. As a technician, this is the phase I stress the most. Getting these details right ensures your new unit works flawlessly for years to come.

Sizing Your Navien Unit Correctly

The biggest mistake you can make is choosing the wrong size unit. It’s not about the size of your house; it’s about your hot water demand.

You need to consider two key factors: flow rate, measured in gallons per minute (GPM), and temperature rise. Temperature rise is the difference between the incoming cold water temperature and your desired hot water output (typically 120°F).

Add up the GPM of all the fixtures you might use simultaneously. For example, a shower (2.0 GPM) and a dishwasher (1.5 GPM) running together require a unit that can handle at least 3.5 GPM at your region’s specific temperature rise. Navien provides clear sizing charts to help with this.

Assessing Your Home’s Infrastructure

A tankless water heater is a high-performance appliance, and it needs the right support systems.

Gas Line: This is a critical safety check. Tankless units require a much larger gas volume (higher BTU) than tank heaters. You will likely need a 3/4″ or even 1″ gas line run directly to the unit. An undersized gas line will cause the unit to fail and produce error codes. Always have a licensed professional verify and, if necessary, upgrade your gas line.
Venting: Navien units are high-efficiency and require specific venting materials, typically PVC, CPVC, or polypropylene. You cannot use the old metal vent from your tank heater. The installation manual provides strict guidelines on vent length, diameter, and termination location that must be followed precisely to ensure safety and proper operation.
Plumbing: The ideal setup is a home with a dedicated recirculation return line. If you don’t have one, don’t worry! Navien’s NaviCirc™ valve is an ingenious accessory that allows you to create a recirculation loop using your existing cold water line.
Electrical: The unit needs a dedicated 120V electrical outlet nearby. It cannot be on a shared circuit.

Your Step-by-Step Navien Tankless Water Heater with Recirculating Pump Installation Guide
This section outlines the process of how to navien tankless water heater with recirculating pump installation. While this guide provides a clear overview, we strongly recommend hiring a licensed and certified technician. This ensures safety, code compliance, and protects your warranty.
Safety Disclaimer: This process involves gas, water, and electricity. If you are not 100% confident in your skills, please hire a professional. Improper installation can lead to gas leaks, water damage, or carbon monoxide exposure.
Safety First: Shut Down All Utilities
Before you touch anything, shut off the main water supply to the house, the gas valve leading to your old water heater, and the corresponding circuit breaker in your electrical panel.
Remove the Old Water Heater
Connect a hose to the drain valve at the bottom of the old tank and drain it completely. Once empty, carefully disconnect the hot, cold, and gas lines. These old units are heavy, so have a helper and a dolly ready.
Mount the New Navien Unit
Choose a suitable interior wall location with proper clearances as specified in the manual (typically 2 inches on the sides, 12 inches on top and bottom, and 6 inches in front). Secure the included mounting bracket to the wall studs and hang the unit.
Install the Venting System
This is one of the most critical steps. Cut and fit your PVC or other approved vent pipes for both the intake and exhaust. Ensure the horizontal runs have the correct slope (typically 1/4″ per foot) back toward the unit for proper drainage of condensation. Seal all joints with the appropriate primer and cement.
Make the Plumbing Connections
We highly recommend using a Navien isolation valve kit. These kits include service valves that make future maintenance, like descaling, incredibly easy. Connect the cold water inlet (right side), hot water outlet (left side), and the recirculation return line (center). Use proper plumbing techniques (e.g., solder for copper, PEX crimps) for all connections.
Connect the Gas Line
Connect your properly sized gas line to the unit’s gas inlet. Use pipe dope rated for gas and check every connection for leaks with a soapy water solution after the gas is turned back on. If you see bubbles, there is a leak. Turn the gas off immediately and correct the connection.
Install the Condensate Drain
High-efficiency units produce acidic condensation that must be drained. Run the provided tubing to a nearby floor drain or condensate pump. Never drain it directly into a metal pipe without a neutralizer.
Commission the System
This is the final and most important phase. Slowly turn the main water back on and open the hot and cold service valves. Open a hot water faucet somewhere in the house to purge all the air from the plumbing lines. Once you have a steady stream of water, you can plug in the unit and turn the gas valve back on. Power up the unit and follow the manufacturer’s startup sequence on the control panel to configure settings, including your recirculation mode.

Optimizing Your Recirculation Pump for Peak Performance
One of the best navien tankless water heater with recirculating pump installation tips is to configure the pump correctly. You have powerful options to balance convenience and efficiency.

Understanding Navien’s Recirculation Modes

Navien’s NPE-A2 series offers three modes:

Intelligent Pre-heating: This is the default and often the best mode. The unit learns your hot water usage patterns over a week and then activates the pump predictively, just before you typically need it. It’s smart, efficient, and provides a great balance.
Always-On Recirculation (Internal): This mode keeps the internal loop hot 24/7 for the absolute fastest response time. It uses more energy and is generally only needed for specific commercial applications.
Scheduled Recirculation: If your family has a very consistent schedule, you can program the pump to run only during specific times (e.g., 6-8 AM and 6-9 PM). This is a fantastic way to create a sustainable navien tankless water heater with recirculating pump installation.

Common Problems with Navien Tankless Water Heater with Recirculating Pump Installation
Even the best products can have issues if not installed correctly. Here are a few common pitfalls to watch out for, which fall under key navien tankless water heater with recirculating pump installation best practices.

Improper Gas Line Sizing

The Problem: The unit “starves” for fuel, leading to error codes, shutdowns, or failure to heat water to the set temperature. This is the #1 installation error we see.

The Fix: Do not guess. Have a professional calculate the total BTU load on your gas meter and ensure the pipe feeding the Navien is sized correctly for its length and the unit’s demand.

Incorrect Venting

The Problem: Improper slope, exceeding maximum length, or using the wrong materials can cause the unit to shut down due to pressure switch errors. More dangerously, it can lead to a risk of carbon monoxide leakage.

The Fix: Follow the installation manual to the letter. Every detail, from the type of cement to the termination cap, matters for safety and performance.

Air in the System

The Problem: After installation, the recirculation pump sounds noisy or struggles to move water.

The Fix: This usually means air is trapped in the lines. The system needs to be thoroughly purged during the commissioning step by running hot water at multiple fixtures until all sputtering stops.

Post-Installation: Your Navien Care Guide
Your installation is complete, but a little routine care will ensure decades of reliable service. This navien tankless water heater with recirculating pump installation care guide is simple to follow.

Annual Flushing and Descaling

If you live in an area with hard water, mineral scale (calcium and magnesium) will build up inside the heat exchanger, reducing efficiency. Once a year, use the isolation valves to flush the unit with a vinegar solution or a commercial descaler. This simple process can dramatically extend the life of your heater.

Clean the Inlet Filters

The cold water inlet and the recirculation inlet both have small filter screens. Check and clean them every six months to a year to prevent sediment from restricting flow and impacting performance.

Frequently Asked Questions About Navien Tankless Installation

Do I need a dedicated return line for the recirculating pump?

A dedicated return line is the gold standard for performance. However, if your home wasn’t plumbed with one, Navien’s NaviCirc™ valve is an excellent accessory. It gets installed under the sink farthest from the heater and uses the cold water line as the return path, allowing you to enjoy the benefits of recirculation without a major plumbing renovation.

How much does a professional installation cost?

The cost can vary widely based on your location, the complexity of the job, and what upgrades are needed. A straightforward replacement might be in the $1,500 – $3,000 range for labor and materials (not including the unit itself), but if you need significant gas line or venting work, the cost can be higher. Always get multiple quotes from certified installers.

Can I install a Navien tankless water heater myself?

While some highly skilled DIYers may tackle the project, it is generally not recommended. The risk associated with improper gas and vent installation is significant. Furthermore, most manufacturers, including Navien, may void the warranty if the unit is not installed by a licensed professional.

Investing in a professional ensures the job is done safely, correctly, and your investment is protected. It’s peace of mind that is well worth the cost.

Your Journey to Endless Hot Water Starts Here
A navien tankless water heater with recirculating pump installation is more than just a home improvement project; it’s an upgrade to your daily life. It brings a touch of luxury, a dose of eco-consciousness, and long-term financial savings.
By understanding the key components of a successful installation—from proper sizing and planning to meticulous execution and post-installation care—you are empowered to make the best decisions for your home. You now have the knowledge to ask the right questions and ensure your project is a resounding success.
Enjoy the endless hot water, and stay comfortable!

Author
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David Clark

Founder & Lead HVAC Specialist at HVACRLY

David Clark is the founder of HVACrly and a certified HVAC specialist with 10+ years working on residential and light-commercial systems. He turns complex heating, cooling, ventilation, and refrigeration topics into clear, actionable guides focused on safety and energy efficiency. When he’s not on a service call, he’s testing tools and writing step-by-step tutorials.