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Should I get a Lochinvar boiler or an HTP? cannot decide

guest1 Member Posts: 2
I am need of a new boiler...mine is over 30 yrs old. I have had a number of estimates. I have it narrowed down to
the Lochinvar Knight WHN085 and the HTP ELite FT 80. I am trying to make the best decision. Has anyone had problems with these 2 boilers? thx


  • Heat_n_CT
    Heat_n_CT Member Posts: 64
    I've got the WHN055, little brother to the 085. Be sure you need the 085, don't let them talk you into the bigger size 'just to be sure". It was like pulling teeth to get my 055 installed. They removed a 58K, but their excuse was the water tank was 30K. Moral of the story, get a handle on your heat loss before you do anything.

    I am just a homeowner and I have no experience with the HTP, but I love the Loch...many hours of entertainment the lat two seasons. And the house is toasty warm with very low bills.
  • Steve Minnich
    Steve Minnich Member Posts: 2,674
    I've installed both and you can't go wrong with either. You're safe either way you go. Now, find a contractor to match the quality of the equipment.
    Steve Minnich
    Minnich Hydronic Consulting & Design, LLC
    [email protected]
  • Paul48
    Paul48 Member Posts: 4,470
    How many sq/ft is the house, and what year was it built? I'll second the sizing caution, and warn you about micro-zoning.
  • Chester
    Chester Member Posts: 83
    edited February 2016
    Same as above...Don't make the mistake of focusing on the quality of the boiler instead of proper sizing, installation and using a contractor you can count on for warranty and service. Personally I think the latter is the most important -- choose the contractor and then go with the boiler they like the best.

    Also make sure whichever unit you choose gets properly dialed in with respect to outdoor reset, etc. Even if they do a beautiful installation, if they walk away leaving everything at factory default settings chances are you will never see anything close to the boiler's AFUE rating. And even if they do adjust the defaults, there's almost no way to really know whether you're dialed in until you've experimented with it for awhile under a range of outdoor temperature conditions.

    Example: I went with a contractor I who installs Bosch. Bosch wasn't even on my radar until I talked with this particular contractor and decided they were the ones to put my trust in. Like Heat-in-CT above, I also had to work hard to convince them to install a smaller unit than they were used to. The installation was picture perfect and by the book but they left everything at the default settings, which in my case was a design day supply water temperature (SWT) of 157F (in other words, the outdoor reset curve was set based on supplying 157 degree water when it's 5 degrees outside). Based on my research here and elsewhere I knew that you want your water temps to be as low as possible-- just warm enough to satisfy the thermostat. But in reality there's no way the manufacturer can know what that is for every installation (so they set conservative defaults), and there's no way for the installer to know for sure when they program the boiler -- best they can do is make an educated guess. Then it's up to you to play with it until you find the sweet spot.

    In my case, with cast iron radiators, I was able to drop the curve down to 114F on the design day. I waited until it finally got cold this winter and then I kept my t-stat at 68 and dialed down the curve 2 degrees at a time until I woke up one morning and the house was 66. So I dialed it up a notch and now I know I've found the sweet spot for my particular situation.

    I think it's very sad that a lot of modcons get sold to people (and by people) who just assume you get 95% efficiency because there's a government label on it that says so. The fact is that modcons only start to become more efficient than a regular boiler with return water temps of around 130F. You only get into the high efficiency range (i.e. close to AFUE) when 1) return water temps are in the low-100s and 2) when the boiler is modulating at low- to mid-fire.

  • guest1
    guest1 Member Posts: 2
    the house is 1700 sq ft built in 1985
  • Paul48
    Paul48 Member Posts: 4,470
    edited February 2016
    And probably has a heat loss of about 25000 btus. You have to get a handle on that before you purchase. Slant/Fin has a free heat loss calculator online. You can do it yourself. It's not that hard.
  • Gordy
    Gordy Member Posts: 9,514
    What type of emitters?

    Look into the Lochinvar KHN, or the HTP UFT.

    These two manufactors, and respective lines offer higher turn down ratios than the standard 5:1. With a higher TDR, and lower low end modulation. Oversizing becomes less critical. Example the KHN line offers the 55, and the 85. Both low ends are with in 300 btus of each other 8.2 k and 8.5 k respectively, and 7:1, 10:1 tdr respectively.

    The uft line the smallest one is the uft 80 with a low end of 8k. Next step up is the uft 110 with a low end of 11k.

    Both good companies.

    If your present system is zoned, and the zones have small loads low TDR is what you need to keep from short cycling, and losing efficiency plus wear, and tear on components.
  • HeatingQc
    HeatingQc Member Posts: 10
    Same as above. A 80 or 85 would be too big. I would go with the KHN055 (best modulation ratio) since I have no experience with HTP.
  • ced48
    ced48 Member Posts: 468
    A WH55 is more than enough boiler for your house-