What We Do | Tankless Pros Az | Phoenix, Az

​Navien Gas Tankless Installation​

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What We Do:

Professional Upgrade from Existing Gas Tank-Type Water Heater to a New Navien NPE-2 Series Gas Tankless Water Heater.

 

At Tankless Pros AZ, every upgrade from a conventional gas tank water heater to a Navien NPE-2 series tankless unit is performed as a complete, code-compliant, manufacturer-specified installation by one or two of our own Navien-trained and certified technicians. We do not subcontract this work. The process is engineered for long-term reliability in Arizona conditions, proper performance, safety, and ease of future service.

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Pre-Installation Evaluation

Before any work begins, our technicians measure the home’s static water pressure and verify flow rates and pressure at key hot and cold fixtures throughout the house. This confirms the system can support the tankless unit (Navien NPE-2 series operates between 15–150 psi) and identifies any existing restrictions, low-flow issues, or pressure problems that should be addressed.

 

We also evaluate gas supply capacity, electrical availability, vent path, and condensate disposal options. Any necessary adjustments or upgrades are identified and discussed up front.

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Safe Removal of the Existing Tank Water Heater

Gas, water, and power are shut off. The old tank is drained, disconnected, and removed. The space is cleaned and prepared. We retain the existing location whenever practical so the new unit occupies the same footprint while converting to a clean wall-mounted installation.

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Solid Wall Mounting

A quality sanded plywood backing board is securely fastened to the wall structure in the original location. The Navien NPE-2 is then wall-mounted to this solid substrate. This provides a stable, vibration-resistant, serviceable installation that protects the unit and the wall while allowing proper clearances for air flow, service access, and future maintenance.

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Venting – Using the Existing Vent as a Sleeve

We reuse the customer’s existing vent (after thorough inspection for integrity, cracks, or blockages) as a protective sleeve/chase. A new 2-inch Schedule 40 solid-core PVC exhaust vent is installed inside the existing vent and extended all the way to the roof.

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At the roof penetration we install a proper rubber weather-transition flashing/boot to create a weather-tight seal. A termination tee (or approved dual-pipe/concentric termination configuration as required by the specific run and local code) is installed so exhaust is properly directed and combustion air is correctly managed. All joints are primed and cemented with approved PVC cement.

 

Horizontal runs are pitched back toward the unit at a minimum of ¼ inch per foot so condensate drains properly. The entire vent system is supported per manufacturer and code requirements.

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Note: For all two-story homes, a side (sidewall) vent termination must be installed.

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Water Connections – All Brass Service Valve Kit + PEX-A

An all-brass service valve kit (isolation valves with integrated purge/drain ports) is installed on both the hot and cold water lines. These valves allow the unit to be isolated and flushed without disturbing the rest of the home’s plumbing.

All water connections from the service valves to the Navien unit and into the home’s piping are made with PEX-A tubing and quality expansion-style fittings. PEX-A provides excellent freeze resistance, flexibility, and long-term reliability. Connections are made cleanly and securely so future service (descaling, filter cleaning, etc.) is straightforward.

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Expansion Tank Installation (When Required)

​An expansion tank is typically installed on a gas tankless water heater only when required by local plumbing code or when a hot water recirculation system is present. Because tankless units heat water on demand rather than storing it, they produce less thermal expansion than traditional tank heaters; however, in a closed plumbing system (common when a pressure-reducing valve, check valve, or backflow preventer is installed), the small volume of water that is heated can still raise system pressure enough to stress pipes, fittings, and the heater itself. Local codes in many Arizona jurisdictions therefore mandate an expansion tank on the cold-water supply whenever the system is closed.

 

When a recirculation loop is added, continuous or frequent reheating of water in the loop can create ongoing expansion cycles, so an expansion tank is recommended (and often required) to absorb the excess volume, maintain stable pressure, and protect the equipment and plumbing. The tank is sized according to system volume and pressure, installed on the cold-water inlet side with the proper air pre-charge, and must remain accessible for inspection and service.

 

Pressure Safety Valve and Discharge Piping

A properly rated pressure relief (or temperature-and-pressure) valve is installed or verified, and full discharge piping is run in accordance with code—typically to within a few inches of the floor or to an approved drain—with no restrictions, reductions, or shut-off valves in the discharge path.

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Condensate Drain

A new ½-inch PVC condensate line is installed from the unit’s condensate outlet, properly trapped and pitched, and terminated to a suitable outdoor location or approved drain. This handles the acidic condensate produced by the high-efficiency condensing Navien NPE-2. Local code and best practices determine whether a neutralizer is also incorporated.

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Gas and Electrical

Gas piping is sized and connected to meet the NPE-2’s input requirements (typically requiring verification or upsizing from a standard tank heater’s line). A dedicated shut-off and sediment trap are provided.

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Electrical note: A new 110-volt GFCI-protected power receptacle, if required, is not included in our scope of work and is performed by others.

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Full System Purge, Calibration, and Startup

Once all mechanical connections are complete and leak-tested:

• The entire hot-water system is purged of air.

• The unit is filled and the condensate trap is primed.

• Gas pressure is verified at the inlet and manifold.

• The Navien is powered up and calibrated exactly according to the manufacturer’s specifications (temperature setpoints, combustion parameters, flow parameters, etc.).

• A complete operational test is performed under load—multiple fixtures are opened to confirm proper ignition, modulation, temperature stability, and flow performance.

• All hot and cold lines throughout the home are re-checked for pressure and flow.

 

Final Steps and Professional Standards

Our technicians clean the work area thoroughly, dispose of the old tank properly, register the unit for warranty when applicable, and walk the homeowner through basic operation, the service valves, filter access, and recommended maintenance (especially important with Arizona hard water).

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Everything is performed to Navien’s installation requirements, the National Fuel Gas Code, applicable Arizona and local plumbing/mechanical codes, and our own internal quality standards. The result is a clean, reliable, high-efficiency tankless system that delivers endless hot water, lower operating costs, and a professional installation built to last.

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This is the complete process Tankless Pros AZ follows on every Navien NPE-2 series upgrade.