Navien NFC-H boiler vs their NCB-H boiler?

eurban

Hello,
Our 2007 con mod boiler needs to be replaced and I have two contractors providing estimates for a new Navien combi boiler. Our old boiler was a Burnham Freedom FCM120 and it provided more than enough heat for our home. I have one contractor recommending the Navien NCB 240/130H and the other the Navien NFC 250/175H. Both boilers produce the same amount of of hot water and both turn down to around 13k BTU's. I do think that the NFC boiler has significantly more capacity than we need but given the similar turn down amounts is there good reason to choose one over the other; Firetube vs whatever the system the NCB uses? Things like longevity, ease of maintenance etc etc. Either contractor is willing to install the NFC but the one feels it is oversized capacity wise, is a bit larger physical footprint, and about $ more expensive. Thanks, and please I am just specifically looking for thoughts on the choice between these two rather than other brands etc. Both contractors are experienced and both work with Navien.

GGross

Choose the boiler that is most correctly sized. Have either of these contractors performed a heat loss calculation or used any other method to actually determine what size boiler you need?

eurban

No recent heat loss calculation performed. Original 2007 120BTU boiler was chosen on calcs done by old contractor with their hands being held by Burnham techs. That said it was probably more BTU's than needed but it certainly didn't turn down to the levels that the Navien's do. We have since added a small kitchen addition that is tight construction with spray foam insulation and a hydronic radiant floor. The Burnham has continued to handle the heating duties just fine.

GGross

I would certainly start with the boiler closest in capacity to what you have then. Personally I would want a load calculation done on the house prior to changing equipment, I don't usually trust that this was done correctly on initial install, especially if the original said "probably more BTU than you need" This just tells me that they have all guessed, which seems ok since it works but it could be better.

As for your other questions

The firetube is generally going to be considered "better" I would imagine by most contractors

Longevity difference between the two is entirely dependant on the quality of the install, double points for the quality of the water in your heating system

ease of maintenance? Well here are some pics of the internals of both boilers, neither looks terribly easy to service, but if your contractors are both familiar with the product they likely have no trouble servicing them

Bschwarzh

Hey eurban, I'm in the exact same situation, with 2 contractors suggesting the 2 combi boilers that were suggested to you. Care to share which one did you end up going with and what factors made the decision for you?

psb75

"Can't mention"other brands...so the Navien "train" chuggs on. Whatever you do...DON'T read the Navien reviews.

GeneBA

NCB model does not have wifi link. NFB and NFC have wifi  ready-link. I have no idea what they are for.