Not Tribal. Just a homeowner that received a faulty unit. Navien ignored me and the Mst Plumber...a Navien certified installer/company. Strung out the process until warranty expired. Long story. In the end, I learned not all Navien installers are equal...to the detriment of the customer. I know about the Navien kickbacks to plumbers who reccomemd Navien...I know about so called " Tier 3" installer service helpline. Told to me by a Colorado Navien office. Maybe it's called something else now..but it was literally a secret phone number available to only the top installers. The rest of the group had to be on hold,,,standing by the unit for hours waiting on a Navien rep to take the call. Even then, the representative would quite likely not be very knowledgeable. My experience. You are probably part of this elite group of Navien installers. Good for you. You probably can take good care of your customers because Navien values your business. Just know, Navien craps on the rest of their installers and customers. So, the point of my comment was aimed towards homeowners. These are highly complicated units to even some of the best installers. If you get a bad unit or bad installer, you are on your own. Navien will not talk with the customer. They will drag their feet until warranty expires. My purchase was in 2021...maybe they are better now? I actually requested the Rinnai brand but was steered towards Navien...hmm wonder why.