Boiler selection

j a_2

What combi boiler makes most sense for a now high mass gravity system and single bath home? House I'm Boston, will be reattaching to existing system c/I radiators...sidewall vented..

Ironman

It's kinda a matter of preference.

The Bosch GreenStar is the quietest I've installed. With the FW200 module you get ODR and intuitive learning where the control learns how often you need heat. The aluminum HX is durable but will require periodic cleaning.

TriangleTube Prestigue Excellence has a fire tube HX with an internal indirect. As far as I remember, it's only available in one size, but with the high mass of your system, that may not be an issue.

The Navien is probably the lowest in initial cost with a good control system, but I wouldn't expect it to last as long as the Bosch or TT.

If you're hiring a contractor to do it, he's the most important part of the equation. Make sure you do your home work on him.

You should also have the old piping thoroughly flushed and install a magnetic dirt separator to protect the new boiler.

RobG

If it's not a financial issue I would go with the TT.

EzzyT

The HTP EFT is also great combi unit just as well as the TT. I've installed hundreds of Navien combi and I've had tons of issues with them.

jonny88

@EzzyT why do you continue to use Navien if you still do if you know they are giving you trouble.All the big guns are coming out with combis now to challenge the Navien market.I believe Baxi have been making them for a long time,a lot to choose from and all competitive with Navien.

EzzyT

I stop using the Navien's a a few years ago once I kept having all those issues with them. I've even swapped out a bunch of them that i originally put in with other manufactures combi units and not have had any issues.

NYplumber

For a quality no frills easy to use combi, look no further then the Viessman 100 series.
For a conventional mod con, the NTI, TT, Viessman, Lochinvar are very good. Worked on them all and theyre all real good. Viessmann has a new CU3A that is new and very well made with good options and perfect for a gravity system that likes slow flow.

Rich_49

Versa Flame and call it a day . PHR130-55c . Have a good day Ja

Xmytruck

@EzzyT what kind of issues ? And was it with the ch model or ncb model?
Thx

Aaron_in_Maine

The key is sizing to the heat loss. Also measure the rads to see how low you can run the water temp. Check the story on my find a contractor page it was a gravity conversion and it condenses all the time the highest temp it runs is 150.