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Mod/con choice

Robert O'Brien
Robert O'Brien Member Posts: 3,541
Vitodens by a mile.Compare a Viessmann heat exchanger to anyone else's.It's not even close.Quality of materials and construction are incomparable.

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  • Jack
    Jack Member Posts: 1,047
    Mod/con choice

    If you were to pick a new gas fired, boiler for your home for a combination baseboard/radiant system, heat only, 80kbtu load, what would you pick? Why?
  • Al Corelli
    Al Corelli Member Posts: 454
    My Choice

    Availability of parts around here, dictates what I install.
    I have to be able to get parts or have parts in stock. The only people who have a great network around here is HTP.

    All these fancy boilers are great. Judging from the quality of the Viessmann Boilers I've installed, I'm sure the quality of their modcons is outstanding, but parts availability from them has been spotty at best. To be fair, though, my Mother's house has a Vitola Biferral, and the Viessmann chassis gas burner has operated flawlessly. But my attempt to get spares for "just-in-case" use has proven difficult.

    Modcons, in general will need more maintenance than a "regular" boiler. They operate at the cutting edge of combustion. There are more sensors and proprietary parts that are going to need to be changed. SOMEONE has to carry all of these proprietary parts.

    The other day, I drove HOURS to get a board for another brand of boiler. HOURS. A boiler that the local power company is "giving away". They require the wholsaler to stock a certain percentage of these boilers to be "part of the program". They only allow the wholesaler to make a miniscule percentage on the boiler, while having to deal with homeowners, who (on average, not like anyone here)can monopolize a salesman's time with technical questions that he may or may not be able to answer. The worst ones are the ones who pretend to be contractors, and then they ask if they can put the ancillary material on a Diner's Club card.
    Why doesn't the local gas company require that the wholesaler carry the parts? Because they don't care about the servicing. They just want to be able to say, "Look at all the high efficiency boilers we are giving away".
  • [Deleted User]

    If budget is not a problem the Vitodens is a perfect choice. There is no comparison to the quality put into this unit. My second choice is the Lochinvar Knight. I have had great success with this boiler in both commercial and residential applications and had no problems. The other good thing about the Lochinvar is there are seven different sizes to choose from. I think the kbn 105 might fit your application.

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  • Kal Row
    Kal Row Member Posts: 1,520

    As modcons are simply not as reliable as the old boilers, one boiler is simply not an option, and the minute you put two in, the obvious choice is the Lochinvar-knight as it comes with the multiple boiler system (“cascade”) built-in

    A system I do, is, two knights, with two Williamson 60 indirects, which are identical to ultra plus 60 indirects – but are a lot less expensive, I pipe the tanks in parallel but stage the tank stats to each boiler with one at 160 and one at 140, so that the first one runs it’s boiler DHW pump into both tanks and drop’s it’s boiler out of the cascade and ramps it up to 180f, while the other boiler is still providing space heat at a much lower temp, and if the DHW load get big enough to drop both tanks to 140, the other boiler’s DHW pump kicks in parallel and drops it’s boiler also out of the cascade and ramps it up to 180, so that you now can handle the full DHW load with priority, but you don’t have to run both when the DHW load is light, this gives you redundancy, electrical load matching, and very efficient "lifetime" DHW that doesnt have to be replaced every 10years

    if you want cheap - use forced air heat and tankles hot water

    See pdf - this one was designed for a house with radiant but with lots of body sprays - needed almost steady hot water
  • hot_rod
    hot_rod Member Posts: 22,158
    Nice drawing, Kal

    and an interesting piping and control logic. I'm wondering if the drawing is conceptal or do you pipe all those bull heads on the circs like shown?

    I've had weird things happen when two flows pull or push against one another with the branch as the "header"?

    Perhaps with that 2" piping it is not a problem?

    hot rod
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • Kal Row
    Kal Row Member Posts: 1,520
    i spring check it to death..

    the pumps are ifc's and the other sides all have spring checks and i have large pipes, so far so good -

    the other way to do this would be to close tee each boiler's output into both a SpaceHeat loop and a DHW loop, which would have added another pair of loop pumps and inserted a single points of failure, though i might have to do heat traps beside the spring checks

    haven’t gotten a good load on it yet – but I will mind your warning – and let you know – thanks

    I’ve got to get me some of that Bavarian water that knows how to follow those arrows around ;)
This discussion has been closed.