Welcome! Here are the website rules, as well as some tips for using this forum.
Need to contact us? Visit https://heatinghelp.com/contact-us/.
Click here to Find a Contractor in your area.

what size boiler?

Options
maybemark
maybemark Member Posts: 1,131
I live in a house that is about 2600 square feet, over 90 years old. 3 layers of brick, no insulation on the walls. i took a heat loss calculator and got 76000 loss, I did not include the basement. i do not have any radiators down there, but the old, way over size boiler keeps the basement at about 55 degrees.
I have new windows and new entry doors.
I just don't know if i am making a mistake on not including the basement for my heat loss, and if I should be getting a larger boiler than i want to purchase.
I am thinking of the Lochnivar whn85.
What do people think?
Any questions you have for me to answer to give you a better understanding of my house?
«1

Comments

  • Gordy
    Gordy Member Posts: 9,546
    Options
    What is your emitter end of the system?

    That boiler will not add much heat to the basement.
  • maybemark
    maybemark Member Posts: 1,131
    Options
    Gordy
    I'm sorry, but I don't know what is an emitter end. i am a carpenter, not a plumber.
    And i know your right, that i probably won't be 50 degrees downstairs with the new boiler. The only heat transfer i will be getting will be from the 2 sets of 2" horizontal pipes i have running for the feeds to my radiators. At one time my system was a gravity fed system. Now i have a 35 year old boiler that is much too large
  • maybemark
    maybemark Member Posts: 1,131
    Options
    Hat
    I'm not sure if my heat loos is correct, because i did not enter my basement, not sure if i am suppose too.
    I have a huge loss because of my walls. 2 layers of brick, 1 layer of clay tile ( 12" total, and plaster directly on the clay tile, no room to put in insulation, unless i build a wall in front of the existing walls and drywall it.
    I live in chicago, I put in 0, for the outside temp and 68 inside
  • maybemark
    maybemark Member Posts: 1,131
    Options
    gordy
    do you mean cast iorn radiators. is this considered the emmitter end?
  • Gordy
    Gordy Member Posts: 9,546
    edited December 2014
    Options
    Emitter would be the radiators, or any other type of heat emitting fixture on the system.

    If your worried just enter the basement in your heat loss at the 50-55* setpoint for indoor temp. It won't add much.

    The only thing about a cold basement unless the floor is insulated it does create a heatloss to the upper floor. Did you enter that in your calcs for the main floor heat loss?

    What calculator are you using?
  • Gordy
    Gordy Member Posts: 9,546
    Options
    Your brick wall detail is a bit better than if it were solid concrete. Much less conductive.
  • maybemark
    maybemark Member Posts: 1,131
    Options
    Gordy
    Thank you for helping.
    i am using the slant fin heat loss calculator.
    When i entered the 1st floor, i considered it as unheated below
    I did try to include the basement, and put in 55 degrees, but when I tried to get the total for the whole house, it made my inside temp as 55 degrees. i don't know if i did something wrong, or if there is a glitch in the calculator
    mark
  • Gordy
    Gordy Member Posts: 9,546
    Options
    In the slant fin I pad version you should be able to enter each room set point independently.
  • maybemark
    maybemark Member Posts: 1,131
    Options
    maybe my brick is better than concrete, but it shows a huge loss on the calculator.
    The biggest thing is, i did not include the basement, and am I making a mistake but not including it, and then really need a larger boiler than an 85,000?
  • maybemark
    maybemark Member Posts: 1,131
    Options
    I don't have i pad, i have a samsung, but your right, each room is individuale. Still, at the end, after putting in all the information, and asking you to calculate, on top, the number i got for an indoor number was 55 degrees. i don't understand it. I chose not to include the basement instead. But by doing this, am I making a mistake, and should i be getting a larger unit instead of the one i am thinking of getting, i only want to do this 1 time
  • maybemark
    maybemark Member Posts: 1,131
    Options
    yes, Chicago is called the windy city, but it does not have strong winds for the most part. The windy city is refering to the politics of the city.
    most people think like you.
    Still, am i getting the proper size unit?
  • Gordy
    Gordy Member Posts: 9,546
    edited December 2014
    Options
    Even if you use the IBR rating it's 69k instead of the doe rating of 79k I think you will be fine. IBR rating is used if boiler, and piping are in unconditioned space. You have a converted gravity system those large pipes will act like a buffer to the system.

    An example I live west of you east of rockford I used -4 for a design temp in my heat loss and I have yet to see the kind of heat loss slant fin showed in my calculations, even at -20'last year in my home. If you knock 10%'off the 76k your still in the IBR output range.

    One thing your wall detail has is mass so even that will buffer you through really cold swings in outdoor temps.
  • Gordy
    Gordy Member Posts: 9,546
    Options
    Also remember the calculator is giving you worst case scenario. How often in our area is it really that cold, and for long durations?

    Your system is going to be poised for some good efficiency out of that boiler. With outdoor reset, and I would slap trvs on all your rads with constant circulation. The whn will percolate in the condensing range most of the season.
  • maybemark
    maybemark Member Posts: 1,131
    Options
    I acually have a few feet of 4" pipe that branch off to 2 sets of 2" pipes.
    I have alot of volume of water in my system. It sounds like a good thing for me.
    So, you feel, not adding the basement to my calculations is ok, and an 85k boiler should be good?
  • Gordy
    Gordy Member Posts: 9,546
    edited December 2014
    Options
    I do. A mod/con would much rather claw its way at heating than coast its way through to get the most out of what it has to offer in efficiency. Now how to control it..... Got a plan?
  • maybemark
    maybemark Member Posts: 1,131
    Options
    Gordy
    I'm not sure when you ask, do i have a plan on how to control it?
    I'm a great carpenter, and i know alot about many other trades, being a general contractor, but hydrnics i know very little about
  • Gordy
    Gordy Member Posts: 9,546
    edited December 2014
    Options
    As I touched on in an earlier post. Controling the emitters(rads) and your boiler piping. Your piping will have very low head loss being a converted gravity system.

    You need to think about sizing circulator for the system.

    You need to calculate the btu output of your existing radiators for each room, and correlate this to the heat loss calculated for that room. If the rad is over sized that is a wonderful thing because it allows lower average water temps which gets you down in condensing range. The lower the return temp to boiler the more it condenses sub 130*.

    That boiler has a lot to offer to optimize efficiency. Utilize it.
  • maybemark
    maybemark Member Posts: 1,131
    Options
    I was just planning on the suggested pumps in the manual. i am wrong to think this?
  • maybemark
    maybemark Member Posts: 1,131
    Options
    and yes, i have large radiators, and have 14 of them in my house, well, the 3 bathrooms and front all are small
  • icesailor
    icesailor Member Posts: 7,265
    Options
    Heat Loss Differences:

    Maybe this will help.

    IBR uses "Factors" to make their computations. They tested and measured different types of surfaces for heat loss. Where I lived and worked, 99% of all buildings were wood framed. Insulated or not. The two factors we always used (from IBR) are for a uninsulated wood framed 2"x4" wall with wall board (gypsum) on the inside, and 1/2" plywood, tar paper and shingles on the outside. The loss factor was ".25".Which meant that for each ONE (1) Sq. Ft of that uninsulated wall space, would loose .25 BTU's per hour per degree difference between the inside and the outside temperature. If the inside temperature was 70 degrees, and the outside was -0 (zero), the 1 Sq. Ft. of wall space , that space would be loosing 17.5 BTU's per hour, Compute the area of the wall and multiply it by 17.5 and you have the heat loss for a bare wall that size. The different types of windows have their areas computed and are given a weighted factor in relation to the heat loss of that wall.

    If you add 3.5 inches of fiberglass insulation, the factor for that same wall drops to ".07" or .07 BTU's per hour per sq. ft. of wall space. Which corrected to the same amount as the above (.27) will be 4.9 BTU's per foot. Almost 3 times less heat loss for just insulating the wall.

    So, a uninsulated wall, 8' X 12' (96 Sq. Ft) will loose 14,000 BTU's on a zero design day but the same insulated wall will loose 3920 BTU's. Baseboard figured at 600 BTU's per foot will be 23.3' of baseboard, while the insulated wall needs only 6'5'. There are other correction factors that come in to play. A uninsulated masonry wall, exposed to the outside has a loss factor of .56. The same 800 Sq. Ft. wall looses 39,300 BTU's per hour and needs 65' of 600 BTU baseboard. I used the program for over 30 years. It NEVER left me in a spot.

    A 2"x 6" wall factor is .05. or 4.66' of baseboard. Install a 5' piece. Where the 2" x 4" wall needed 6.5', you use 7' of baseboard. You save 2'' of baseboard.

    The concept is there. I hope my dyscalculia/ADD math is correct.
  • Gordy
    Gordy Member Posts: 9,546
    Options
    https://heatinghelp.com/systems-help-center/sizing-circulators-for-old-gravity-hot-water-systems/

    Read this it will be helpful in deciding the water temps your system will use. And circulator.
  • maybemark
    maybemark Member Posts: 1,131
    Options
    Ice
    thank you for the lesson, but this is not helping me with my house.
    I have 12" of masonry, no insulation about 2600 sq ft, not including the basement. Though the basement averages 50 degrees or so on winter days, it is not heated with radiators. i imagine the 35 year old boiler that is way oversized and the 2" horizontal pipes help make the basement around 50 degrees.
    I used the slant fin heat loss calculator, but i did not include the basement in the calculations, I don't know if I made a mistake not including the basement. My heat loss, after going room by room, and figuring all the factors came to about 76000 heat loss.
    my wuestion is, will a lochinvar whn85 boiler be a proper size for me
  • maybemark
    maybemark Member Posts: 1,131
    Options
    gordy, that was very interesting
    right now my 35 year old boiler has been using a taco 007 pump.
    For the Lachonvar whn85, they call for a grundfos 15-58, which i was planning on using.
    what do you think?
  • Gordy
    Gordy Member Posts: 9,546
    edited December 2014
    Options
    Lets get the EDR of those rads you have. Got pics? I think the on board 15-58 may do the job that circ comes with the boiler.

    We need to determine type of radiator, the height, and the number of sections. Each radiator correlated to each room.
  • icesailor
    icesailor Member Posts: 7,265
    Options
    maybemark said:

    I acually have a few feet of 4" pipe that branch off to 2 sets of 2" pipes.
    I have alot of volume of water in my system. It sounds like a good thing for me.
    So, you feel, not adding the basement to my calculations is ok, and an 85k boiler should be good?

    You really have a very difficult situation to deal with. One can really drop off the earth in your situation. You've been given a lot of really good suggestions. If you choose to go with some type of Mod Con type boiler, that's your and the installers choice. I lived in a location that now has a rating that isn't listed with IBR/AHRI and the closest location is set as way warmer than it will get where I lived. I don't have my old grey IBR H-22 heat loss guide, but I am sure that Chicago was listed well near Zero or below. And it was U. Illinois, Urbana that did the testing to come up with the low temperatures for the calculations. ACCA Manual "J" doesn't give a rats about how cold it is, you don't need AC when it is cold.

    You really need to consider using a high mass boiler that will be adequate for your situation and not try to go out on any edge. You have no idea how much your house can or will lose if it is brick and can't be insulated. Infiltration is the biggest factor and can't be accurately "Guestimated". Because your house was once a gravity system with 4" mains still in place, I would highly recommend that you consider a Taco "I" Series 4 way valve to run your system. It will automatically adjust the system temperature inside the system by changing the water temperature in the system, but NOT the boiler. If you are running a converted/pumped former gravity system now, I guarantee that you have some radiators that are much hotter than others and those rooms are hotter than others. With the 4-way mixer, if the ODR/OAT control decides you need 130 degree water in your system, ALL the water going into the system, and all the radiators will be 130 degrees. The whole house will be one temperature. You can install TRV's if you want, but you will need the flexibility of controlled and mixed hot water. When I first started plumbing in 1964, the boss had a big job that used a Honeywell 3-way valve to provide even heat in a well designed system. I didn't know a lot, but I knew it worked well. I spent years looking for a similar valve but no one made them and what were made were for commercial applications and way to big for my use. One day, I found the "I" series 4-way and threw one in on a problem house just like yours. I was absolutely STUNNED at how well it worked. So was the owner. No more 90 degrees in the front hall over the boiler and the kitchen in the back of the house always had cold radiators unless you turned the heat up to 90 degrees.

    Be extremely careful about downsizing a house that is uninsulated and will be difficult to do so. Stop every bit of infiltration you can. All the new Federal Energy Regs, don't take your house into consideration. Those high heat loss numbers might be the real thing.

    Been there, done that.

  • Gordy
    Gordy Member Posts: 9,546
    Options
    ICE what exactly are you trying to say????
  • maybemark
    maybemark Member Posts: 1,131
    Options
    gordy
    i had all the rad and dimensions written down, but the paper is gone, after i was told that is used only for steam systems, and not hot water.
    if it would be help, i can measure and count the columns, or take photos.
  • Gordy
    Gordy Member Posts: 9,546
    edited December 2014
    Options
    You can use EDR for hot water also you need to determine how many btus the rads can put out correlate it to the heat loss for the room it serves, then you will know if the rad is oversized, or not. Oversized is good it allows you to use lower AWT.

    1square foot of EDR is equivalent to 150 btus at 170 AWT.
  • maybemark
    maybemark Member Posts: 1,131
    Options
    Ice, i'm sorry, but you lost me. i am want to know if people think in my size house and heat loss, not including the basement, will an 85k HE boiler work well for me
  • SWEI
    SWEI Member Posts: 7,356
    edited December 2014
    Options
    maybemark said:

    For the Lachonvar whn85, they call for a grundfos 15-58, which i was planning on using.
    what do you think?

    I would not use a fixed-speed circ for that purpose in this day and age. If there's just one or two zones, I would look at the Taco VT2218. If you have a lot of zones or are planning on using TRVs, one of the many ΔP options would be my choice.
  • Gordy
    Gordy Member Posts: 9,546
    Options
    I see from your other discussions you have gone through quite a gauntlet of back and forth decisions. I did notice from your other discussions you somehow determined 150 AWT how did you get that number.

    Swei also makes a good point on the Circ choice.
  • SWEI
    SWEI Member Posts: 7,356
    Options
    Left out the note that if you do use an ECM circ, a magnetic dirt separator will help ensure its continued survival in an old system full of cast iron. Flush well before and after you install as well.
  • maybemark
    maybemark Member Posts: 1,131
    Options
    Swei
    I only have 1 heating sone, and a priority zone will be for my indirect hot water. I already bought the 2 pumps, but, if you really feel i should have something different, maybe i should consider it.
    I also already bought a dirtmag
    thaks
    mark
  • maybemark
    maybemark Member Posts: 1,131
    Options
    gordy
    yes, i have gone back and forth on what i should put in my house, main reason is, my best friend, my plumber, is old school, and not well versed on HE boilers. He still thinks, but in a stadard boiler, as big as you think. i am learing different from this site, and he will install what is suggested. So, i do appreciate all the comments
    150 awt, to be honest, i don't even know what that means
    thanks
    Mark
  • Gordy
    Gordy Member Posts: 9,546
    Options
    Average water temperature to the radiators. So say 160 supply 140 return for an average across the radiator of 150
    maybemark
  • maybemark
    maybemark Member Posts: 1,131
    Options
    thank you, I did come up with this number. i might be wrong, but i thought somone from WM told me this number, i might be wrong , what i am seeing, 140 to 180 for DHW, does that sound right?
  • Gordy
    Gordy Member Posts: 9,546
    edited December 2014
    Options
    You have to look at the charts for your indirect selection. usually 180/190 is what they are based on with X gpm flow rate through the indirect heat exchanger.

    Those numbers are probably 140 DHW tank temp. !80 supply from the boiler to heat the indirect.
  • maybemark
    maybemark Member Posts: 1,131
    Options
    Like i said, i might be wrong, at times this becomes a bit overwheliming for me.
    do you think i should get thos other pumps?
    I just purchased 2 grundfos 15-58, but if the others are better, i will consider it. Will the grunds not work?
  • Gordy
    Gordy Member Posts: 9,546
    Options
    MArk its not that simple. This is a science. I gave you the tools related to sizing a circulator for gravity conversion systems. You need to know the EDR of the rads to use it. I can give you the EDR if I know the type of radiators, and how many sections each one has, and their height. you just dont buy a circulator, and hope it works.

    The WHN 85 comes with a 15-58 3 speed circ on board already. this will be what drives the primary loop.

    So you need one for the indirect, and one for the secondary loop for the heating end.

    I dont know what indirect you are using so I cant even answer if a 15-58 will work for that.
  • maybemark
    maybemark Member Posts: 1,131
    Options
    gordy
    i had all the radiators sized measured, how many sections, but the paper is gone, i can re-make it, if you can help me, would it be best i write it down and send it to an e-mail.
    I am going with a 40 gal lachivar