Navien NCB Boilers

Navien NCB Boiler Overview

The Navien NCB is a condensing gas combination boiler with an efficiency rating of 95.0% AFUE. It was named an Energy Star Most Efficient 2015 product and is available in three models — NCB-180, NCB-210, and NCB-240. It is designed to save space and occupies up to 80% less space than a traditional floor standing boiler with tank water heater. The NCB features dual corrosion-resistant stainless steel heat exchangers with a separate stainless steel flat plate heat exchanger for domestic hot water. The system can use 2″ PVC for venting up to 60 feet and can easily be converted from natural gas to propane operation. For situations with very high domestic hot water demands, the NCB can be cascaded with Navien’s NPE tankless water heaters.

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Consumer Reviews of Navien NCB


  • Very Satisfied
  • Somewhat Satisfied
  • Neutral
  • Somewhat Unsatisfied
  • Very Unsatisfied
  • #2 of 4 Navien Boiler
  • 32% of customers recommended

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Navien NCB Boiler Reviews

Showing 16-20 of 25 reviews

"Stay away from Navien"

2.0 rating
Somewhat Unsatisfied

My original Navien was installed in 2012. No problems for 5 years. In March of 2017, the heat exchanger started leaking. The unit had to be replaced. The good news; the unit had a 10-year heat exchanger warranty, so it would be replaced for free. The bad news; I had to pay my plumber $2,000 for the labor. Yesterday, three months after the unit was installed, no hot water. Called the plumber. He and Navien Tech determined the internal pump went bad — not covered by warranty — because it's a replacement unit, with a 30-day parts warranty. Wtf!! I'm not out $300 for the replacement part plus labor fees. Overall the unit is good, but heaven forbid anything goes wrong. I will never purchase a Navien product again.

Donald L.

Boston, MA

"The most important part is the proper installation"

5.0 rating
Very Satisfied

I have been installing these boilers professionally for over five years. In those five years I have over 100 of them installed in various applications from basic baseboard to huge mono flow systems requiring multiple boilers to work together. Of all the units I put in, I have had issues with two of them. One was a pump failure and the other was a bad board. The pump failed because of debris. I put a strainer on and never had the problem again. I started putting in special receptacles in to clean up the power and the board problems went away. Just like you plug your computer and TV into a surge protector, you need to protect the circuits on any of these high technology appliances. They are computers and susceptible to power fluctuations. The most important part of the installation is the installer. If the price is too good to be true, it usually is.


Hawthorne, NJ

"Great combi boiler"

1.0 rating
Very Unsatisfied

My ncb-240 has been great so far. No problems. These need to be installed correctly, and your water has to be good or tested. Most of these complaints are probably from bad installations. Great value.


Moorhead, MN


1.0 rating
Very Unsatisfied

"Garbage!" If you plumber recommended to you a Navien hot water boiler, hire new plumber, if you installed already- go to Home Depot and buy a couple of electric heaters as well because your going to need them when your unit continuously fails. I had a NCB 240 installed in couple different customer, each one have lot of problem, now I me ridge with this garbage. Every couple month it has failed, it was flame loss then two way valve quit working now my igniter switch is junk, in each boiler pressure sensor need to replace after 3-6 month. The idea of saving money because it's high efficiency goes right out the window when you use Navien product. Do your research before you buy and save yourself the headache.

Dan Kozyurak

West Babylon, NY

"Don't ever buy a Navien"

1.0 rating
Very Unsatisfied

Haven't had heat nor hot water since Sunday night 4/11. We've been having issues with our Navien combo boiler since installing it 1-1/2 years ago. Worst customers service! 3 different plumbers say it's a bad unit, but the rep for Navien, Repcor, said it's the install, Speaking to these people is like talking to AT&T…Ridiculous – no help! We just want our money back.

Chris Bradbury

Reno, NV

Other NCB Reviews

Online reviews of the NCB appear to be mixed. On, a post from a homeowner trying to choose between the NCB and a similar Lochinvar unit found most replies favoring the Lochinvar, although one member stated that he liked his NCB and had no problems with it. In another post on the site a member mentions that Navien has updated their boiler line three times in five years, and for that reason he cannot support the product.

NCB Warranty

The warranty for the Navien NCB boiler is comprised of the following:

  • 10-year heat exchanger warranty
  • 5-year parts and other components warranty
  • 1-year labor warranty

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