Condensing Boiler versus Navien

SpeyFitter

I'm curious if any of you who have worked on these units extensively, feel about the "worthyness" of a Navien Tankless Unit in comparison to some of the better Condensing Boilers out there e.g. Viessmann, TT, Lochinvar, etc.. Navien seems to be trying to "edge" their way into the heating market with the "heating box," thing. But somehow this just does not sit right with me as I don't think they are built as stoutly from what I have heard, as  your typical boiler. They are also going after the "combi" market, if there is really one, with a gas combi heater that they now offer.

While both of these types of units need servicing, I have this feeling in the back of my head that even a decent condensing boiler is built in a more robust fashion in general as it is purpose built. I also question the reliability due to the some of the growing pains I've heard they have had, of the Navien units. One guy who I see post every now and then suggests some of the Noritz, Takagi, etc, more inefficienct non-condensing models from a tankless model are built like brick you know whats, but Navien I think is the first one to go after the Condensing edge.

Not to strictly bash Navien - I believe they are one of the first, if not the first, to try and go for the condensing edge in tankless heaters. And tankless heaters do have a time and place (athough I find it hard to find that exact time and place in a lo of scenarios). But call me old fashioned, but I really like a condensing boiler matched perfectly to the heating load, with a nice, reliable, no-nonsense stainless steel indirect tank.

CMadatMe

It's a water heater

Wasn't to familar with the tankless heater you spoke about so I went to the web site to check it out. My first thought is that it is not listed as a boiler its a water heater. I would be curious to what grade of stainless the heat exchanger is made of.

I couldn't open the installation manual on their web site but I would be curious as to see the piping arrangement for a domestic/heating system.

TonyS

Navien heat box

I have been installing Naviens for over a year now, at first they had a little trouble with the flow switch but since then have fixed the problem. Every one I sell loves them including me in my own home and I have had no trouble. I am looking for the right job to experiment with the heat box. The warranty on the Navien is 15 years on the exchanger and even if the unit has to be replaced every ten years its still a good buy. I would like to Know more on the Heatbox beyond the basics like outdoor reset controls. If and when I get a chance to use one I will post it. If anyone else has expeirience please post.