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boiler replacement in 90 unit apartment building

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ari
ari Member Posts: 9
in Strictly Steam
I manage an apartment building in NYC which needs a new boiler. The building has 90 apartments totaling approximately 103,000 sf, has a FST-200 boiler with an ICI DEG-84 burner (Heat Input: 8.2 Million BTU/Hr.) The boiler has a coil which provides domestic hot water and therefore runs all year round.
I was wondering if it is economical to replace this boiler with multiple smaller boilers. This would provide some measure of redundancy for steam, as well as the ability to make hot water half the year without heating up a massive boiler.
Finally, the existing equipment can fire on #2 oil in case of a gas emergency, and we would prefer to retain this ability if possible.

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  • Steamhead
    Steamhead Member Posts: 16,856
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    I've worked on those FST boilers. You could cremate someone in there and no one would know >:)

    What caused the present boiler to fail?
    All Steamed Up, Inc.
    Towson, MD, USA
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
    Consulting
  • ari
    ari Member Posts: 9
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    Its almost 30 years old and has been leaking. We have been welding plates in there for a while, and now we need to replace one tube sheet and its tubes.
  • Steamhead
    Steamhead Member Posts: 16,856
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    Sounds like the system has been losing a lot of water. Fresh water being fed all the time will drastically shorten the life of a boiler. The water feed line to the system should have a water meter on it to keep track of this.

    How much radiation is in the building?
    All Steamed Up, Inc.
    Towson, MD, USA
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
    Consulting
  • ari
    ari Member Posts: 9
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    The system has been losing much water. Return lines are all repaired now but the damage has been done.

    We have not yet measured the amount of radiation in the building, this is more of a ballpark does it make sense question, before we head down the more obvious road.
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 15,546
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    The IC model "D" burner Is in some configurations capable of burning heavy oil. I am assuming you no longer need that capability is this correct? Your staying with gas/#2 oil?

    yes you could certainly install say (2) 100hp boilers which would be capable of 4,200mbh each (your existing boiler is 200hp) HB Smith 28HE is what I would use Weil McLain has a similar boiler. For burners you could go with Webster or PowerFlame gas/oil burners I prefer the Webster

    I would strongly recommend 2 things. Absolutely by the burners with "full modulation" do nor accept LO-HIGH-OFF or LO-HIGH-LOW operation your IC burner I am sure is full modulation.

    Take the time to size the boiler(s) properly by doing a take off of the existing radiation.

    Most important is the right contractor
  • Mike_Sheppard
    Mike_Sheppard Member Posts: 696
    edited February 2018
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    EBEBRATT-Ed said:

    The IC model "D" burner Is in some configurations capable of burning heavy oil. I am assuming you no longer need that capability is this correct? Your staying with gas/#2 oil?

    yes you could certainly install say (2) 100hp boilers which would be capable of 4,200mbh each (your existing boiler is 200hp) HB Smith 28HE is what I would use Weil McLain has a similar boiler. For burners you could go with Webster or PowerFlame gas/oil burners I prefer the Webster

    I would strongly recommend 2 things. Absolutely by the burners with "full modulation" do nor accept LO-HIGH-OFF or LO-HIGH-LOW operation your IC burner I am sure is full modulation.

    Take the time to size the boiler(s) properly by doing a take off of the existing radiation.

    Most important is the right contractor

    Just curious as to what your reasoning is for full modulation only. 99% of what I deal with as a service tech is full modulation burners, but I have read quite a bit about low/high/low being more efficient than full modulation in some cases. Ray Wohlfarth mentions this a lot in his books as well as some ASHRAE studies if I am not mistaken. I'll try to dig that up.

    Edit: This wasn't what I was searching for but it's from one of his books.

    https://heatinghelp.com/systems-help-center/are-modulating-burners-really-worthwhile/
    Never stop learning.
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 15,546
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    Nope, Cant happen

    Low high lo can never be more efficient than full modulation. Full modulation modulates the burner to maintain a set point either hot water temp or steam pressure. The burner flame is positioned between lo and hi fire at any position required to maintain that set point.

    Some burner manufacturers call two position or lo-hi firing "modulation" i's not the same at all. LO-hi-lo only has 2 different firing rates lo and high.

    Full mod has an almost infinite number of firing rates.....anywhere between lo & hi
  • Mike_Sheppard
    Mike_Sheppard Member Posts: 696
    edited February 2018
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    https://www.pmmag.com/ext/resources/PM/2013/August/080-082-0813_Wohlfarth.pdf

    I am fully aware of the difference. I'm not saying that's wrong at all. But studies have shown that in some situations, taking into account ALL efficiency concerns of a boiler, such as jacket loss, combustion efficiency, short cycling, etc, a low/high/low can actually be more efficient. I'm sure this is situational, but interesting to read about.
    Never stop learning.
  • the_donut
    the_donut Member Posts: 374
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    A lot less to troubleshoot on Weil McLain low hi low fire compared to full modulating board. I am pretty pleased with our 1500 mbtu unit for a 26 unit apartment building which is massively oversized.
  • scott22nyc
    scott22nyc Member Posts: 7
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    I have had a similar question in the past, but never knew where to go for an answer. The NYC steam companies I use just want to replace what was there with the same. Can anyone recommend a true expert commercial steam consultant in NY?
  • Mike_Sheppard
    Mike_Sheppard Member Posts: 696
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    scott22nyc said:

    I have had a similar question in the past, but never knew where to go for an answer. The NYC steam companies I use just want to replace what was there with the same. Can anyone recommend a true expert commercial steam consultant in NY?

    Keep looking until you find someone willing to do it the right way. I don't know that area so I don't know any recommendations, but I do know it is WELL worth the money to have it done properly.
    Never stop learning.
  • nicholas bonham-carter
    nicholas bonham-carter Member Posts: 8,578
    edited February 2018
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    Have you tried the find a contractor button on the website here?
    I wonder if full modulation burners would be better for hot water boilers, instead of steam.—NBC
    Is this one-pipe or two-pipe steam?
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 15,546
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    @Mike_Sheppard , If you look at Rays article he describes "2 OVERSIZED BOILERS" with full modulation.

    What I suggested above on this job was to "Take the time to size the boiler(s) properly by doing a take off of the existing radiation"

    2 correctly sized boilers without unnecessary redundancy and with full modulation will match the load without short cycling. They will only need 1 boiler to run during most of the heating season

    Ray is correct in that in most large boilers the combustion efficiency falls off on low fire and that combustion efficiency is improved on high fire. It also falls off on lo-high fire burners. It's the same burner.

    There is also heat loss up the chimney when the boiler cycles off. So it is a trade off in my opinion.

    The most important thing is the right size equipment ....and the contractor
  • Dave0176
    Dave0176 Member Posts: 1,177
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    For boilers this I’d recommend Clever Brooks, you can run them dual fuel. Probably two 150 HP boilers and full modulation burners. Easco boiler is in NYC but I’m not much of fan of their boilers, to me Clever Brooks has them beat.
    DL Mechanical LLC Heating, Cooling and Plumbing 732-266-5386
    NJ Master HVACR Lic# 4630
    Specializing in Steam Heating, Serving the residents of New Jersey
    https://heatinghelp.com/find-a-contractor/detail/dl-mechanical-llc

    https://m.facebook.com/DL-Mechanical-LLC-315309995326627/?ref=content_filter

    I cannot force people to spend money, I can only suggest how to spend it wisely.......
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 15,546
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    @Dave0176
    just wondering why you would go with (2) 150s as he just has (1) 200 now which may be oversized? Until he checks the radiation who knows??

    Depends on access as well, Easco I think does site built boilers if need be.

    I have no problem with Cleaver except refractory issues. My choice for a scotch would be a wetback. I always liked those better.
  • leonz
    leonz Member Posts: 1,140
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    Before you spend any money you should look at the Hurst boilers as they make multifuel, hybrid and coal boilers as as well as scotch boilers.

    www.hurstboiler.com
  • jumper
    jumper Member Posts: 2,265
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    Eight million seems big? Is there any DHW storage at all? I presume there's a superintendent living on premises? If so multiple boilers is a good idea. Off line boilers can be isolated.
  • ari
    ari Member Posts: 9
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    There is no DHW storage, and yes there is a resident super.
  • lostinheating
    lostinheating Member Posts: 31
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    > @scott22nyc said:
    > I have had a similar question in the past, but never knew where to go for an answer. The NYC steam companies I use just want to replace what was there with the same. Can anyone recommend a true expert commercial steam consultant in NY?

    I know gs dunham does steam not 100% sure about boilers. They maybe able to spec what you need. Give them a call. Great guys and definitely do things right.

    And you could always hire a mechanical engineer,same to original poster.
  • leonz
    leonz Member Posts: 1,140
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    Check with the Hurst boiler folks they do everything from start to finish.
  • ari
    ari Member Posts: 9
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    Can anyone recommend a good steam-qualified mechanical engineer in the NYC area?
  • lostinheating
    lostinheating Member Posts: 31
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    Ralph Germaine is good. Don't have his number handy
  • jumper
    jumper Member Posts: 2,265
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    I remember a 28 suite building with HHW that used heating boiler for DHW. Seemed that 24/7 on boiler (steel fire tube) lasted forever. Eventually to conserve energy switched to separate water heaters. About ten years later that big bad heating boiler died. Does shutting off burner for summer kill the boiler?
  • leonz
    leonz Member Posts: 1,140
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    It will rust just like a coal stoker boiler or furnace. Its best to clean the firebox and tubes, disconnect the flue pipe cap the flue breech and chimney thimble and put in a couple of work lights with good shock load resistant incandescent bulbs to keep the boiler warm and check the work lights every week to be sure to replace the burned out bulbs as needed.
  • p0ncho
    p0ncho Member Posts: 1
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    ari said:

    Can anyone recommend a good steam-qualified mechanical engineer in the NYC area?

    I may be able to help, I sent you a private message.

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