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New Apt Owner - Bad Combi Heater - Suggestions Please!!!

BKCOMBI
BKCOMBI Member Posts: 6
Hello! I am a new apartment owner in a coop in Brooklyn. It's only a single bedroom with a bathroom/kitchen (about 900 square feet), and I inherited a very dodgy Laars Endurance 175 EBP (old blue style) combi heater that runs on natural gas and supplies the hot water for my unit as well as the hot water for the radiator system (hence the combi, as I've learned). It's experiencing major problems (which I will not go into here), and I am in no way interested in investing money to keep it patching it up.

So: I NEED TO BUY A NEW COMBI BOILER. Digesting so much information out there, but this is a big investment. Does anybody have any solid recommendations for a combi boiler given my situation? I've been looking at the LAARS Mascot Sytem again (like the wall mounted FT or LX), but I don't completely understand the real differences between some of the systems. Some neighbors have a Baxi system, but I see horrible reviews online. Looking for something that will be consistent for the next 10/15 years and easily available parts/servicing in the NYC area.

I also want to potentially use the new Nest thermostat! Many things to consider. Trying to figure it all out. I would love any recommendations or advice. I have a great plumber, but need to make a final decision about what unit to actually purchase

Comments

  • Jamie Hall
    Jamie Hall Member Posts: 23,164
    The first step is to figure out how much heat you need -- probably not much, but you need to know anyway -- and what your hot water demand will be. Then you can begin to decide which unit might work best. There's no point in getting one which is too big -- although I expect, when you come up with the heat loss for your apartment and your hot water demands, you'll find that the hot water demand is what will govern the size of the unit, and the heating side will be wildly oversized. Can't be helped with a combi.

    I would pay very little attention to on-line reviews; they are heavily biased to the negative. What is important in choosing a unit is to choose one which your preferred installer likes to work with and is willing to maintain.

    On the Nest. Well... with a fair amount of patience and trial and error, they can be made to work reasonably well with hot water heating systems. Not great, and there are a number of other thermostats which are a good deal cheaper and work a lot better, but that's your choice.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
    CanuckerSuperTech
  • Many boiler problems are caused by a bad installation, and the online reviews usually come from unhappy people whose installation went wrong, rather than people who are happy with the outcome.
    Make sure your plumber is well versed in hydronics, and let him be the guide, as he will be giving it the annual service for the next 15 years! You can find other experts here by using the find a contractor button.—NBC
  • BKCOMBI
    BKCOMBI Member Posts: 6
    edited December 2018
    Thanks, I have a feeling I should be fine with a ~100,00 BTU unit. Just hoping to get some feedback from folks with deeper knowledge of COMBI units. Got a great plumber lined up, just want to buy the most reliable system out there!
  • nibs
    nibs Member Posts: 511
    Am a newbie here, have learned through reading here and studying, that in lay terms, you need to get the smallest (lowest powered) unit that will heat your home on the coldest day you are likely to get. That calculation is very important for efficiency and longevity of the new unit.
  • Le John
    Le John Member Posts: 226
    @BKCOMBI - I recently installed a Lochinvar Noble Combi and love it. It works very well and provides more than enough hot water. The heating side can be lowered to 10% of its maximum output helping to reducing and minimize short cycling. The control is simple to program.
  • HVACNUT
    HVACNUT Member Posts: 5,804
    Your installer needs to be a licensed dealer but you could look into the Energy Kinetics System 2000.
    IMO (space providing) much better than a combi.
    A Carlin EZ gas burner can be setup to provide much lower BTU's than a combi would need for DHW.
    Properly installed and with the Energy Manager, it's quite the boiler.
    Very easily to install and service. No clogging flue or water passages. No yearly vinegar flush. Just smooth sailing.
    They offer a stackable if space is limited.
    SuperTech
  • BKCOMBI
    BKCOMBI Member Posts: 6
    Thanks! I'm also considering these if I stay with the combi boiler route:

    Laars Mascot FT Combination MFTCW140, 133,000 BTU
    Laars Mascot LX Combination 125 Combi
    Bosch Greenstar 100 Combi Wall Mounted Boiler Model ZWB28-3
    Westinghouse WBRCNG140W 140K BTU Natural Gas Wall Comb
    Noritz CB180 - Condensing Boiler 180,000 BTU Propane Direct Vent Indoor
    Rinnai M Series NG Condensing Boiler/Tankless, 90,000 BTU Input
  • Jamie Hall
    Jamie Hall Member Posts: 23,164
    You have quite a range of heat output there. Do your arithmetic on heat and domestic hot water loads first. Then pick a good installer. Then pick a boiler he or she likes to work with.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
    kcoppCanucker
  • HVACNUT
    HVACNUT Member Posts: 5,804
    You say you have a great plumber, and I'm sure you do.
    Have you asked him/her their recommendation? Its been said over and over again here newbie, so you're forgiven just this once.
    The installer is just as, if not more important than the equipment. They must be experienced with installation and service of YOUR system.
    Your plumber might be great with a Lochinvar, but never even heard of Laars or Bosch. You dont want that.
    CanuckerDZoro
  • BKCOMBI
    BKCOMBI Member Posts: 6
    I do have a great plumber, and he works with a large number of different units. There is a lot of variety here in NYC. He said that the LAARS Mascots are still popular (especially in the northeast), and also mentioned the Westinghouse units. I am a newbie, so I am looking for SECOND OPINIONS on the equipment itself. In almost any industry, there is often knowledge that some hardware/equipment could be more reliable than others, provided a clean install.

    As for the units I listed above, those were the combi boilers from each manufacturer that best match my heat and domestic water needs. Don't need anything more than 100K BTU, so those are the least powerful from each. Just trying to get some feedback on the dependability of these units, or maybe get pointed in a new direction. These are the ones I am considering the most:

    Laars Mascot LX Combination 125 Combi
    Bosch Greenstar 100 Combi Wall Mounted Boiler ZWB28-3
    Westinghouse WBRCNG140W - 140K BTU Natural Gas

    Thanks again for your help!
  • HVACNUT
    HVACNUT Member Posts: 5,804
    edited December 2018
    > @BKCOMBI said:
    > I do have a great plumber, and he works with a large number of different units. There is a lot of variety here in NYC. He said that the LAARS Mascots are still popular (especially in the northeast), and also mentioned the Westinghouse units.

    Ok, that's awesome you have a reliable guy ready to go.

    Sorry I cant help any with the mod cons.
    Can I talk you into converting to oil?🤪
  • Alan (California Radiant) Forbes
    Alan (California Radiant) Forbes Member Posts: 3,979
    edited December 2018
    900 square feet? And you're looking at boilers in the 100,000 BTU range? That's 100 BTU's per square foot when you consider 90% efficiency which is crazy when you probably only need ~25 BTU's per square foot. Your boiler will be short-cycling like crazy.

    Don't get a Baxi - they are troublesome.

    I've had very good luck with the Rinnai e50c combi boiler since we do a lot of small jobs. But you have to be OK with a reduced domestic hot water output; only about 2 gallons per minute which means you can use no more than one or two normal plumbing fixtures at a time.

    https://s3.amazonaws.com/s3.supplyhouse.com/product_files/Rinnai-E50CN-Product-Overview.pdf

    https://forum.heatinghelp.com/discussion/comment/1541292#Comment_1541292
    8.33 lbs./gal. x 60 min./hr. x 20°ΔT = 10,000 BTU's/hour

    Two btu per sq ft for degree difference for a slab
    SuperTech
  • sallaberry
    sallaberry Member Posts: 19
    Why not a navien or viessmann 100.
  • BKCOMBI
    BKCOMBI Member Posts: 6
    I agree that the 100K BTU appears to be overkill, but I really can’t seem to find a combi boiler unit below that right now. Wouldn’t a high efficiency unit also like the Lars Mascot FT also keep down the cycling? Still open to ideas and new directions.
  • Canucker
    Canucker Member Posts: 722
    @BKCOMBI don't take this the wrong way but we're trying to offer you a new direction, that you yourself said you'd be open to. The heat loss calculation is a good idea, if for no other reason than to put an upper limit on the equipment size. I have a feeling that a 900 sq ft apartment with attached neighbors is going to have a heat loss smaller than the smallest Combi will provide, and that's a recipe for a very short life for the boiler. It's a little troubling that your plumber hasn't explained how this works to you. It sounds like you've got your heart set on a Combi and while that may be the best choice, there are questions that need to be answered before you decide that.
    You can have it good, fast or cheap. Pick two
    SuperTech
  • kcopp
    kcopp Member Posts: 4,418
    How much room in the boiler/ mechanical room is there? A properly sized wall hung boiler w/ a small indirect water heater would be the best way to go... Again use the boiler that your installer knows the best, can easily get parts for & can fix it when and if there is an issue.
    Canucker
  • eddo
    eddo Member Posts: 12
    As others have said, 100,000 BTUs for 900 square feet? wow! My house in cold Vermont, with average insulation, is 1,200 sf, is heated just fine with a 13,000-50,000BTU Rinnai E50c. And, again, as someone else said, the only thing to be aware of is that the DHW rate is only 2.1 gallons per minute, fine for our 2 person house. One thing I learned in my research to install my own boiler is that old-school HVAC guys often suggested boilers that are waaaayy bigger than necessary, which might have something to do with old leaky houses not having insulation way back when.
    SuperTech
  • pecmsg
    pecmsg Member Posts: 4,775
    How many outside walls in this 900 sq ft coop?

    Units above or below?
  • Alan (California Radiant) Forbes
    Alan (California Radiant) Forbes Member Posts: 3,979
    edited December 2018
    The Laars FT combi starts at 140,000 BTU's. Not a good choice in my opinion because of the high input.

    The Rinnai e50c is 50,000 BTU's and will modulate down to 13,000 BTU's which is where you will be running most of the time; steady-state efficiency.

    You could also go with a small IBC combi:
    http://usa.ibcboiler.com/wp-content/themes/ibc/pdf/DC-Series-Sales-USA.pdf

    or the small Viessmann combi:
    https://www.viessmann-us.com/en/residential/gas-boilers/condensing-boilers/vitodens-222-f.html

    The Viessmann model modulates down to 12,000 BTU's and has a 26 gallon DHW storage tank which is great for buffering peak demand.

    All three are excellent choices and they are all below 100,000 BTU's.

    Whoever installs it, make sure they are familiar with both plumbing and hydronic heating and whatever boiler you finally choose.

    8.33 lbs./gal. x 60 min./hr. x 20°ΔT = 10,000 BTU's/hour

    Two btu per sq ft for degree difference for a slab
    SuperTechCanucker
  • JohnNY
    JohnNY Member Posts: 3,226
    Something doesn't seem right here. You've got a great plumber yet you're online asking for boiler recommendations.
    Who in Brooklyn is recommending Westinghouse boilers?
    I don't know a single wholesaler in NY or NJ that carries the line.

    Are you sure you don't just have a cheap plumber and maybe not such a great one?
    Contact John "JohnNY" Cataneo, NYC Master Plumber, Lic 1784
    Consulting & Troubleshooting
    Heating in NYC or NJ.
    Classes
    pecmsgAlan (California Radiant) ForbesSuperTechCanucker
  • pecmsg
    pecmsg Member Posts: 4,775
    JohnNY said:

    Something doesn't seem right here. You've got a great plumber yet you're online asking for boiler recommendations.
    Who in Brooklyn is recommending Westinghouse boilers?
    I don't know a single wholesaler in NY or NJ that carries the line.

    Are you sure you don't just have a cheap plumber and maybe not such a great one?

    100K BTU's for 900 Sq Ft Coop

    Great Plumber!!!
    Alan (California Radiant) ForbesSuperTechCanucker
  • Alan (California Radiant) Forbes
    Alan (California Radiant) Forbes Member Posts: 3,979
    edited December 2018
    Yeah, I was trying to be nice, but tough love here is totally appropriate : )
    8.33 lbs./gal. x 60 min./hr. x 20°ΔT = 10,000 BTU's/hour

    Two btu per sq ft for degree difference for a slab
  • HVACNUT
    HVACNUT Member Posts: 5,804
    edited January 2019
    Um, excuse me boys. I believe we were told by Mom to type as if our friends are here. Which I why I'll keep my mouth shut. I dont want to be sent to bed before the ball drops.
    Who am I kidding, I'll be snoring by 10 after a bucket o wings.

    I still vote for a stackable EK Gas Frontier as long as proper venting is achievable.
  • SuperTech
    SuperTech Member Posts: 2,139
    edited January 2019
    I'll add my two cents.

    Please listen to everyone here regarding boiler sizing. I see boilers and furnaces fail prematurely all the time with my job as a service technician. The most common factor is that the equipment is grossly oversized for the load on it which causes them to short cycle to death. It's already a problem because the design of any combi boiler usually makes them too large for the load due to the fact that they have to heat DHW on demand. An indirect tank or separate water heater is a better way to go.

    I really like Energy Kinetics boilers with the EZ gas burners, very reliable and they seem to last forever but I'm not sure how low of a firing rate you can get out of them for that small application.
  • Alan (California Radiant) Forbes
    Alan (California Radiant) Forbes Member Posts: 3,979
    edited January 2019
    I think BKCOMBI abandoned us for whatever reason I can't fathom.

    Happy New Year everyone!
    8.33 lbs./gal. x 60 min./hr. x 20°ΔT = 10,000 BTU's/hour

    Two btu per sq ft for degree difference for a slab
    JohnNY
  • BKCOMBI
    BKCOMBI Member Posts: 6
    Hey guys! I didn't abandon this discussion yet. Got distracted with the New Year. I am digesting all of this today. That being said, happy New Year everyone! Also, my plumber did not recommend those units specifically. They were rather the smallest combi boilers for those brands I could find online at that moment, and I now understand the importance of getting a unit that is properly sized for my apartment. I did a heat loss calculation, and I would need something in the ~40K range. I will probably have more questions later. Thanks again for all the help!
  • DZoro
    DZoro Member Posts: 1,048
    Lochinvar Noble would be a good choice if your contractor handles and services them.
    D