Click here to Find a Contractor in your area.
Welcome! Here are the website rules, as well as some tips for using this forum.

If you've found help here, check back in to let us know how everything worked out.
It's a great way to thank those who helped you.
Need to contact us? Visit https://heatinghelp.com/contact-us/.

New Boiler with indirect

3zht3zht Posts: 3Member
Good morning all, I've been reading as much information online such as this website and getting great information. My situation is a little different as I have a 1978 tri-level house that has a furnace on the second floor only so we can remove that from the equation, I believe. I know how many therms I used per month but it's difficult for me to guess if the therm's are being used by the boiler or my gas furnace (see my dilemma?).

The first floor (1st zone) (900sq ft with 1 bed, 1 bath, and a living room. 100 feet of baseboard)
Third floor (2nd zone) (900 sq ft with 3 bed, 2 baths. 80 feet of baseboard)
Garage (3rd zone) 2.5 car with 45k btu modine hydronic heater running off boiler (heated to 45-50F only)

Gas bill was over $500 in January so I insulated the attic (previously had R19 in attic) and now it's R39. All windows and doors have been replaced with updated efficient models. My current boiler is original to the house and is 200k BTU input, 160k BTU output which seems VERY overkill. If I'm not mistaken I have my house needing just under 80k BTU to heat.

I have had a few contractors come in and they all seem to want to install the Navien 240E combi. After doing all my research and calculations I'm looking more at a mod con boiler with a direct fired 50 gal as we have two small children who need baths.

I was looking at the Lochinvar knight boilers and didn't know if the wall mount/floor mount made a difference. Also I'm thinking the 110N may be better than the 80N because the 110N has a net BTU of 89. Am on I base to make the correct decision here? I'd hate to have a boiler that can't warm my house during these -10 nights.

Comments

  • Intplm.Intplm. Posts: 434Member
    The contractors that you have had over and have made suggestions? Gave you their expert advice? Are they the same people who will be servicing your system. If so, and I hope that they are.
    Keep in mind that you are buying a product and service that goes along with that product. The company, and product that they install should be integral with each other.
  • EBEBRATT-EdEBEBRATT-Ed Posts: 5,271Member
    @3zht
    #1 you need an accurate heat loss...no guessing or measuring baseboard heaters that doesn't work. You can down load the Slantfin app and do it yourself if need be. Then you will have the right size boiler.

    200k input is way too large to heat two floors
  • ZmanZman Posts: 4,688Member
    You want to be focusing on the minimum turndown, not the maximum. After all, it is the typical days consumption that will save you money.
    Your house has plenty of radiation so a mod con will be able to run at low temps and efficiently. The 80 is obviously plenty for your load. It has a very similar minimum to the smaller models, so no harm if you over size it a bit.
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • 3zht3zht Posts: 3Member
    Thank you all very much for the time and the expertise. I downloaded that slantfin app and it was wonderful. I believe I filled it all out properly and I'm showing a heat loss of just under 50k. The lochinvar knight 110 goes down to 10,450btu while the 85 goes down to 8,075k btu.

    My issue is this. Contractor wanted to install 150 which is way oversized obviously. I had to talk them into the 110 because they refused the 80k btu model. Now, if I convince them to install the 80k model I can easily see something going wrong in the future and them saying "This is why we wanted to install the 110". Is the small amount of extra BTU's worth that argument or should I just go for the 110?
  • EBEBRATT-EdEBEBRATT-Ed Posts: 5,271Member
    @3zht ,
    This is like bypass surgery. If your contractor won't cooperate get a second opinion.

    How your contractor selects the size of the boiler tells a LOT about his qualifications. A heat loss is the only way ...for hot water heat.

    Basing the size on the old boiler wrong!
    on square footage wrong!
    on measuring baseboard wrong!
  • 3zht3zht Posts: 3Member
    I'm at least leaning toward the 80k btu model now. Thank you! I'll stay up to date with how it goes.
  • ZmanZman Posts: 4,688Member
    The 110 is oversized but not grossly oversized. I don't think you will have any issues going with it. The 80 would be the correct choice.
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • CrawlerHeroCrawlerHero Posts: 5Member
    The Lochinvar Noble Combi 199 could be a great solution for you. Depending on the ground temperature of water where you're at, it will handle the domestic HW load no problem and is more than enough for heating. 10:1 turndown.
  • STEVEusaPASTEVEusaPA Posts: 2,710Member
    edited March 20

    The Lochinvar Noble Combi 199 could be a great solution for you. Depending on the ground temperature of water where you're at, it will handle the domestic HW load no problem and is more than enough for heating. 10:1 turndown.

    Why almost 3x oversized? Just for domestic? Are they filling a 4 person hot tub every night?
    And what does ground water temp have to do with it?
    steve
  • JellisJellis Posts: 91Member
    @STEVEusaPA
    The original post states they have baseboard and a modine heater so no it would not just be for domestic water.
    Ground water temp would affect the amount of GPM of hot water that can be produced, and the OP mentioned having children that took baths. Certainly a valid thought.

Sign In or Register to comment.

Welcome

It looks like you're new here. If you want to get involved, click one of these buttons!