Replacing boiler - too many choices

[RK2]

So I need to replace a failing boiler and I'm thinking it would be real nice to reclaim the chimney for the wood stove - both for emergency and makeup heat for the coldest days of winter. Did the heat loss calc with HE2 and I'm coming out to about 55 to 65Kbtu/hr using 70F inside 0F outside - which I'm hoping is a somewhat correct outside temp basis for southern Maine.

So the question then becomes what boiler? I've sort of narrowed it down to the Burnham MPO, Biasi B10, Buderus G115, or, if I can get a decent price, maybe the Viessmann Vitorond 100. Anyone have an opinion on these in a DV configuration? Other than AFUE and sizing I have little to go on.

[hvac1000]

I would go with the boiler brand that your heating company is going to install.
They know what is best for your situation. Wood stove in the existing chimney? I would call out a chimney sweep and have them inspect the chimney for compatibility with a wood burner. Missing tiles,cracked liners, are just a few of the problems you may be facing.

The new style boilers are not user/homeowner friendly as far a install goes or service unless you have a bunch of tools/meters and know how to use them.

[johnsp]

All are good. I would pick the Biasi, only because a Riello is available and it's lower volume then the Buderus.

Is your chimney large enough to support 2 liners? I would avoid DV in oil
fired anything. Just not worth the lock-outs and staining of the house siding.

[RK2]

Don't think the chimney will fit two liners - it's only 20x16 on the outside which - given that it's regular brick - leaves little space inside. Besides, relining is a couple thousand bucks in my experience, which is more than I'd like to spend on top of the replacement.

My main problem in heating the place is lack of baseboard. 38 ft downstairs and 8 upstairs in the bathroom. I can expand downstairs to about 62, which still only gives about 42Kbtu/hr total - at least 10Kbtu/hr short. Adding addtl. baseboard upstairs is not too hard since it's open beam ceiling in a post and beam, but it's going to be expensive nonetheless since it should really be a second zone and requires quite a bit of piping.

The only thing I'm not factoring in is the cost and install of the DV kit - don't know what that would be extra ... maybe enough for the second zone? Add o that moving a propane tank and oil tank cause it'd be too close to the DV ... probably going to cost about the same in the end?

So, let's assume chimney ... still the same boiler choices or can I go cheaper and get similar efficiency?

[RK2]

So, I think I've settled on going the chimney route, now I am wondering why I would spend the money on an expensive boiler - looking at the stats for the Burnham V83 it says 86% AFUE @ 91KBTU/hr. This is very close to what the more expensive boilers get, so the question is why would I pay so much more for a three-pass design? Are there other factors I'm not seeing that would allow the more expensive ones to use much less oil?

[RK2]

And - sorry to keep posting instead of thinking then posting one big message - how does the Burnham LE series fare? Not sure on the price, but given that I might be able to get a rebate from Burnham I'm not sure it'd be economically rational to not take that offer and go with someone else unless there are big advantages.

[johnsp]

If you're not doing radiant and you're gonna have to run the boiler @ 180 degrees because you're short baseboard/radiators, then no there's no need for the most efficent boiler. The LE is a low volume steel boiler (I got one in my house on copper fin tube). If you had big cast ron rads, I'd suggest a cast iron boiler with more water volume.

What are you doing for Domestic Hot water? You need an indirect for the LE,
no tankless coil.

[RK2]

Have a coil now - thinking of temporarily going electric tank until I either sell the house or decide to stay and get indirect.

Given the settings I'll be running the thing at, would a V8 series run sufficiently close to something like an LE or Biasi? On the Burnham side I'm not even sure which is considered a more desirable boiler - V8 or LE.

[johnsp]

I think the 2 Burnham boilers serve different needs. Only one size on the LE with different firings. Only the smaller firing rate is Energy Star rated.
With a 6 gal capacity, I wouldn't run it against a gravity converted system: too much cold water return. I have low volume copper fin tube zones with an indirect so I need the boiler running all year. I wanted quick heat up's and have limited space. The V8 is a better and only choice if you need larger the 140K BTU's and a coil.

If you're staying long term: get an indirect.

[RK2]

Planning on indirect. It's just that I have a fairly new unused electric tank in another property. Saves the $1,000+ investment for now.

So since I have up to 65KBTU heat loss, how does the following sound for possible choices: the Biasi at 58K (or 96K?) net, the V83 at 79K net, or the LE at 64K net? Slantfin's HE2 software tells me that I can possibly lower the loss to somewhere between 50K and 60K by better insulation, so does that put the 58K output of the Biasi in the right ballpark?

Money is going to be an issue here, so I'm thinking that whatever I save on boiler investment I can put into additional baseboard (and insulation).

[johnsp]

You have to think about your future hot water needs. If it's large, the recovery on a 58K output boiler is gonna be slow to an indirect. Remember you can always go with a boiler one size larger and down-fire it slightly.