(206) 949-5683, Top Rated Plumber, Seattle
Results 1 to 14 of 14

Thread: Screwed by Sandy: Need a new boiler/domestic hot water heater, might as well upgrade?

Hybrid View

  1. #1
    DIY Junior Member Sean Jacobs's Avatar
    Join Date
    Nov 2012
    Location
    NY
    Posts
    5

    Default Screwed by Sandy: Need a new boiler/domestic hot water heater, might as well upgrade?

    Hi Forum!
    I'm excited to be posting here for a first time but sad it's under such circumstances.

    I'm looking for advice from a range of professionals as to what to do. Our boiler (63k BTU New Yorker) was completely submerged as were all the controls. Also our 40 gallon hot water heater was submerged (both with salt water). Both were natural gas fired. We also had to tear up carpet (a good time to remodel to hardwood floors) in two of the rooms. The upstairs previously was on one zone and the basement on a separate zone. While we install new floors I figured it would be good to do radiant heating (I'm sure I can install that part myself). Since the whole thing needs to be replaced, should we go high efficiency? Combo unit? Indirect hot water heating? Other? Sky's the limit I suppose? I had one plumber tell us we should upgrade the size to 96k BTU for better performance but the more I read about these systems I'm not so sure that's a good idea. We have 1000 sq ft on main floor with three sides (~95 linear feet of exterior walls and one party wall with a total of ~100 sq ft of windows. In basement we have about 600 sq ft with 16" thick concrete foundation. He justified the bigger boiler by telling me (and 14 other condo owners) that it should be about 50 BTU/sq foot which would give us a need for around 80k BTU. I feel like this might be high based on what I've read here. Thoughts?

    Exhaust venting shouldn't be a problem since it's close to an exterior wall if needed. Also, would love to get units off ground as much as possible in case of another 'incident'. There are two bedrooms that I'm putting the radiant in and the living room still has the baseboard (will upgrade living room to radiant when the floor starts to buckle and needs to be replaced/kitchen remodel) so in total it'd be 4 zones (2 radiant + 2 baseboard) (eventually 3 radiant + 1 baseboard). I was planning on using 1/2" PEX in loops of around 300 ft for the bedrooms. Strips of 3/4" plywood over 1/4" foam insulation with concrete filling in around the PEX.

    If somebody could help me design a system I'd be willing to pay for that service if it's from somebody I trust but it needs to happen sooner than later as currently we have no heat and hot water up here in NYC and winters'a'comin.

    I appreciate the help!

    -Sandy Survivor
    Last edited by Sean Jacobs; 11-22-2012 at 12:41 PM.

  2. #2
    In the Trades Tom Sawyer's Avatar
    Join Date
    Nov 2010
    Location
    Maine
    Posts
    2,942

    Default

    Definitely high efficiency. Take a look at buderus,lochnivar,triangle tube and others.
    [B]No, plumbing ain't rocket science. Unlike rocket science, plumbing requires a license[B]

  3. #3
    Master Hot Water Mpls,MN BadgerBoilerMN's Avatar
    Join Date
    Mar 2011
    Location
    Minneapolis
    Posts
    285

    Default

    Sorry to hear about the flood. We design hydronic heating systems and specialize in condensing boilers.

    chrome://newtabhttp//www.badgerboile.../products.html

  4. #4
    Retired Defense Industry Engineer jadnashua's Avatar
    Join Date
    Sep 2004
    Location
    New England
    Posts
    21,412

    Default

    There are lots of threads that can guide you on how to determine how much heat your old boiler was providing. I have no idea why, if your old boiler was heating the place, the guy thinks a bigger one is now necessary! Often, in a condo, you have some common walls, minimal exterior walls, and therefore a low heat load. An indirect should not be considered as part of the heating load, and you should NEVER upgrade the size of the boiler for its use unless you run something like a spa that is constantly using lots of hot water...the IWH is configured as a priority zone so that it gets ALL of the heat from the boiler when it needs it. Unless you live in a drafty barn, you'll never notice it's stopped heating the space while it rewarms the WH. Once the WH has come up to temp, things return to normal space heating. I wouldn't be surprised if you couldn't use a (probably much) smaller boiler. You'd need your last winter's gas bills along with those from the summer to figure out what part of that was water heating verses the old boiler. then, the heating degree day info and you can then figure out how much heat you were using. Try to find a boiler that is that size, which will almost certainly be still a little big - the closer you can get without going under, is what you really want.
    Jim DeBruycker
    Important note - I'm not a pro
    Retired Defense Industry Engineer; Schluter 2.5-day Workshop Completed 2013, 2014

  5. #5
    DIY Junior Member Sean Jacobs's Avatar
    Join Date
    Nov 2012
    Location
    NY
    Posts
    5

    Default

    Quote Originally Posted by jadnashua View Post
    There are lots of threads that can guide you on how to determine how much heat your old boiler was providing. I have no idea why, if your old boiler was heating the place, the guy thinks a bigger one is now necessary! Often, in a condo, you have some common walls, minimal exterior walls, and therefore a low heat load. An indirect should not be considered as part of the heating load, and you should NEVER upgrade the size of the boiler for its use unless you run something like a spa that is constantly using lots of hot water...the IWH is configured as a priority zone so that it gets ALL of the heat from the boiler when it needs it. Unless you live in a drafty barn, you'll never notice it's stopped heating the space while it rewarms the WH. Once the WH has come up to temp, things return to normal space heating. I wouldn't be surprised if you couldn't use a (probably much) smaller boiler. You'd need your last winter's gas bills along with those from the summer to figure out what part of that was water heating verses the old boiler. then, the heating degree day info and you can then figure out how much heat you were using. Try to find a boiler that is that size, which will almost certainly be still a little big - the closer you can get without going under, is what you really want.
    Thanks for the replies do far. We are in a condo yes but an end unit so more exterior/non-shared walls and a ground floor unit which is bigger than all others because of the basement and questionable insulation in ceiling to second (of 3) floor. All units in condo originally had the same size boilers and since we only closed and moved in in June we don't know what the winter is like yet...

  6. #6
    DIY Junior Member Sean Jacobs's Avatar
    Join Date
    Nov 2012
    Location
    NY
    Posts
    5

    Default

    You think combo unit or indirect or other for go water and why?

  7. #7
    Master Hot Water Mpls,MN BadgerBoilerMN's Avatar
    Join Date
    Mar 2011
    Location
    Minneapolis
    Posts
    285

    Default

    Every space heating job, be it renovation or new construction start with a Manual 'J' heat load analysis. If you don't know the load that the condo presents, you don't know anything. Once you have a proper heat load you then can make informed decisions about heating space and hot water with one combi appliance. When designing heating systems for condominiums we most often use condensing water heaters with radiant floors, walls and ceilings and occasionally even through in a fan coil if we have to. There are few condos that are big enough to justify the smallest gas-fired boilers made.

  8. #8
    Retired Defense Industry Engineer jadnashua's Avatar
    Join Date
    Sep 2004
    Location
    New England
    Posts
    21,412

    Default

    My personal experience with a combo was not good, but then that's one of millions that are in use. If you live there long enough, you'll probably live to curse a combo. They require more maintenance, and tend to cost more to run verses the use of an indirect.

    Your heat load is probably less than 25KBTU, but that's just a guess. The only way to tell is to analyze what you have...WAG based on square feet will always oversize unless you live in a drafty warehouse. Often, radically oversize.

    Condo builders like consistency - buy 50 units the same, get a great price, teach one guy to install them, and not worry about the efficiency as long as it works. As you've noted, not all of the units are the same in configuration, exposure, location or sizing...therefore, it is highly doubtful they each need the same sized unit. If what you have heated the unit for 6-years, there's no way you need a larger one. Larger both costs more to buy, but also to run. The most efficient is the one closest to what you need. Ideally, it would run 100% of the time when in the middle of a cold snap - heat that goes on and off is not anywhere as comfortable as that that is running all the time. Each on/off cycle wastes heat and hits efficiency. A larger unit than needed will cycle more, wear out sooner, and cost more to operate.

    It is important to size the thing, and a WAG doesn't cut it!
    Jim DeBruycker
    Important note - I'm not a pro
    Retired Defense Industry Engineer; Schluter 2.5-day Workshop Completed 2013, 2014

  9. #9
    DIY Junior Member Sean Jacobs's Avatar
    Join Date
    Nov 2012
    Location
    NY
    Posts
    5

    Default

    Quote Originally Posted by BadgerBoilerMN View Post
    Every space heating job, be it renovation or new construction start with a Manual 'J' heat load analysis. If you don't know the load that the condo presents, you don't know anything. Once you have a proper heat load you then can make informed decisions about heating space and hot water with one combi appliance. When designing heating systems for condominiums we most often use condensing water heaters with radiant floors, walls and ceilings and occasionally even through in a fan coil if we have to. There are few condos that are big enough to justify the smallest gas-fired boilers made.

    I called you guys and left a message last night. Hoping to talk to somebody sooner than later about some stuff.

  10. #10
    In the trades Dana's Avatar
    Join Date
    Jan 2009
    Location
    01609
    Posts
    2,720

    Default

    BadgerBoilerMN tells it true when he says, "There are few condos that are big enough to justify the smallest gas-fired boilers made.".

    The notion that you should bump it up to a 96KBTU unit is insane. If your heat load really adds up to 50 BTU/ft @ +15F (the 99% outside design temp for much of L.I. & NYC) it means you need to close the doors or put glass back in the windows (you were gonna do that anyway, right? :-) ) Even on older housing it's pretty common to see true heat loads under 15BTU/ft, or even under 10BTU/ft. But no "BTU/ft" rule of thumb has any accuracy- heat loss is about exterior surface area, U-factor/R-value, and air leakage, which varies quite a bit, and is not a ratio of the floor area of the conditioned space.

    Micro-zoning an already small heat load will cause modulating condensing boilers to short-cycle into low-efficiency and an early grave. A condensing HW heater based solution is self-buffering and can't short-cycle. It would usually work for radiant zones, but may prove a problem for baseboard zones without upgrading the heat emitters. This is not something suitable for a "design-by-web-forum" approach.

    It's also true that in a coastal NY/NJ climate heating one more more zones with an inverter-drive ductless mini-split heat pump can make sense (even with low-cost gas and high-priced electricity), and has the additional benefit of being able to air-condition with the same equipment. It's not as luxuriant-cushy as radiant floors, but more comfortable than heating with fin-tube baseboard or ducted hot air.

  11. #11
    Master Hot Water Mpls,MN BadgerBoilerMN's Avatar
    Join Date
    Mar 2011
    Location
    Minneapolis
    Posts
    285

    Default

    Quote Originally Posted by Sean Jacobs View Post
    I called you guys and left a message last night. Hoping to talk to somebody sooner than later about some stuff.
    Better to start with an email. I design and install for a living, this is my hobby...:-).

Similar Threads

  1. Replies: 5
    Last Post: 11-20-2012, 08:01 AM
  2. Replies: 3
    Last Post: 02-06-2011, 01:33 PM
  3. Indirect domestic HW from heating boiler
    By John in herndon in forum Boiler Forum
    Replies: 4
    Last Post: 01-23-2010, 09:48 AM
  4. Water heater capacity upgrade
    By export in forum Plumbing Forum, Professional & DIY Advice, Tips & Tricks
    Replies: 7
    Last Post: 05-28-2008, 12:50 PM
  5. State domestic electric water heater
    By mariner in forum Plumbing Forum, Professional & DIY Advice, Tips & Tricks
    Replies: 3
    Last Post: 03-10-2007, 03:55 PM

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •