Navien Water Heater Installation & Repair

5.0 Rating (15 Reviews)
Licensed & Insured
Serving Sonoma & Marin County
Same-Day Service Available

CNTRline Plumbing installs and repairs Navien tankless water heaters across Sonoma and Marin County, including the NPE-2 series (up to 11.2 GPM, 0.96 UEF) and NCB combi boilers. We handle new installs, tank to tankless conversions, annual descaling, and error code diagnostics. Navien covers residential heat exchangers for 15 years. Our local water runs 7 to 10 grains hard, so regular service matters here. Call (707) 308-5599.

The CNTRline Plumbing Team

Licensed Plumbers, Rohnert Park, CA. Licensed and insured. Updated July 3, 2026.

CNTRline Plumbing has installed and serviced Navien tankless water heaters in Sonoma and Marin County since 2017. We are licensed and insured, and we work on every NPE and NCB unit in the field, from first generation models to the current NPE-2 line.

Why Navien fits North Bay homes

Navien's condensing design pulls extra heat out of the exhaust. That is how the NPE-2 series reaches 0.95 to 0.96 UEF against about 0.62 for a standard gas tank. Condensing also means cool exhaust, so most units can vent in 2 inch PVC instead of metal flue, which keeps conversion costs down in older homes.

The A2 models carry a built-in recirculation pump and buffer tank. That ends the cold water sandwich and cuts the long wait for hot water in the single story ranch layouts common in Rohnert Park and Santa Rosa. Every NPE unit is field convertible between natural gas and propane, which matters on rural properties in west Sonoma County. Built-in freeze protection covers our occasional frost nights.

Navien repair near you

We diagnose and repair Navien units in Rohnert Park, Santa Rosa, Petaluma, Cotati, Novato, San Rafael, and the surrounding North Bay. If your unit is flashing an error code or the shower keeps going cold, call (707) 308-5599. If the unit is past saving, read our replacement cost guide before you decide.

Models we install and service

NPE-A2 series (NPE-180A2, NPE-210A2, NPE-240A2): condensing tankless with built-in recirculation pump and buffer tank, 0.95 UEF
NPE-S2 series (NPE-150S2, NPE-180S2, NPE-210S2, NPE-240S2): standard condensing tankless, up to 0.96 UEF and 11.2 GPM
First generation NPE-A and NPE-S units (2012 to 2021): still common in North Bay homes, parts remain available
NCB-H combi boilers (NCB-190/080H, NCB-240/130H and other H sizes): space heating and hot water from one wall-hung unit
NCB-E combi boilers: the earlier combi line, which we still service and repair

Common Navien problems

Hard water scaleWater in Sonoma and Marin County runs about 7 to 10 grains per gallon. That is hard enough to coat a Navien heat exchanger in mineral scale within a year or two. You will notice temperature swings, weaker hot water flow, and eventually overheat or exhaust errors. We recommend a descaling flush every 12 months on city water, and every 6 to 9 months on well water or homes that run recirculation all day. Navien's warranty does not cover scale damage, so skipped flushes get expensive.
E003 ignition failureThe unit tries to light three times, fails, and locks out. Common causes are a partly closed gas valve, low gas pressure from an undersized line, a dirty flame rod, or a blocked intake. Check that your gas is on and other gas appliances work. If the code comes back after a reset, it needs a proper diagnosis.
E012 flame lossThe burner lights, then the flame drops out while the unit runs. We usually trace E012 to a gas supply problem, a dirty intake air filter, or a wiring and ground fault. Wind hitting a bad vent termination can also blow the flame out.
E110 exhaust blockageE110 means the unit cannot push exhaust out or pull combustion air in. We find plugged vent terminations, bird and wasp nests, crushed intake screens, and vent runs that sag and pool condensate. Clearing the blockage and correcting the vent slope usually fixes it.
Flow sensor problemsIf the unit will not fire on small draws, or the temperature hunts up and down, the flow sensor is a prime suspect. Scale and grit jam the small turbine that measures water flow. Cleaning the inlet filter screen fixes many cases. A worn sensor or o-ring gets replaced.
Condensate drain clogsCondensing units produce acidic condensate that has to drain. A clogged condensate line backs water into the unit, triggers safety shutdowns, and drips where you do not want it. We clear the line, check the trap, and add a neutralizer where code requires one.

What we do

New Navien tankless water heater installation, sized to your fixtures, gas supply, and winter water temperature
Tank to tankless conversions, including gas line upsizing from 1/2 inch to 3/4 inch or 1 inch
Annual descaling and full service flush through isolation valves, about an hour on site
Error code diagnostics for E003, E012, E110, flow sensor faults, and the rest of the fault list
Warranty-aware repairs with genuine Navien parts, plus unit registration on new installs
Recirculation setups: A2 built-in pumps, NaviCirc crossover valves, and HotButton on-demand kits

Frequently asked questions

How long do Navien tankless units last?

Plan on 15 to 20 years, sometimes more. The heat exchanger carries a 15 year residential warranty, which tells you what Navien expects from it. The catch is maintenance. In our hard water, a unit that never gets descaled can scale up badly in 3 to 5 years.

How often should I descale my Navien in Sonoma County?

Every 12 months on municipal water. Go to every 6 to 9 months if you are on a well, run a recirculation loop all day, or notice temperature swings before the year is up. Local water carries roughly 7 to 10 grains per gallon of hardness, and the flush takes about an hour through the isolation valves.

What does Navien error code E003 mean?

Ignition failure. The unit tried to light three times and gave up. Check that the gas valve is open and your other gas appliances work. If gas is flowing, the usual suspects are a dirty flame rod, low gas pressure, or a blocked vent. A reset may clear it once, but a repeat code needs a diagnosis.

Do you install recirculation for faster hot water?

Yes. NPE-A2 models have the pump and buffer tank built in. For homes without a dedicated return line, we install Navien's NaviCirc crossover valve at the far fixture. HotButton kits run the pump on demand, so you are not heating pipes all day.

What warranty comes with a new Navien?

Residential NPE units carry a 15 year heat exchanger warranty, 5 years on other parts, and 1 year on labor. We register the unit for you and use genuine Navien parts on repairs. Keep up the annual descaling, because scale damage is not covered.

Free Homeowner's Guide

The Sonoma & Marin Homeowner’s Plumbing Guide

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5 signs to call before it floods
Where your three shutoffs are
Real 2026 cost ranges for the big jobs

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