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Boiler piping opinions

OhioboilerOhioboiler Member Posts: 3
edited December 3 in THE MAIN WALL
Hi, does this look right? I think the pump should be moved to between the air separator and the manifold (does it matter if vertical or horizontal?). The installer originally put it between the dirt magnet and boiler, but I told them I designed it to pump away. It’s a Noble 110, with alpha2 pump to cast iron rads, each equipped with TRV. Any other things I should look at? They had never put a home run system with TRV before. I designed this with help from many of you, so thanks


  • hot_rodhot_rod Member Posts: 12,020
    It’s a combi? If so it has a Circ inside. Primary secondary is what the manual recommends
    Full flow piping is an option in some cases where you can assure adequate flow
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    The magic is in hydronics, and hydronics is in me
  • SnowmeltSnowmelt Member Posts: 1,131
    is that a aqua pure descaling filter or a sediment filter
  • GroundUpGroundUp Member Posts: 669
    He obviously did not read the manual. As mentioned above, the Noble has an onboard circ and needs to be P/S according to Lochinvar. I'd make him fix it. You'll have problems regardless of circ placement without P/S, as there may be instances where only one or two TRV are open which will not provide adequate flow through the boiler
  • hot_rodhot_rod Member Posts: 12,020
    With a pump in the boiler and if the other is in the supply I think you have two in series pumping at the expansion tank? Not the best piping if this is correct?
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    The magic is in hydronics, and hydronics is in me
  • OhioboilerOhioboiler Member Posts: 3
    Thanks for the reply’s. I am confused. I used the Caleffi Hydronics manual as the model for this, where they show a “home run” system. Although I’m sure most of you know this book backwards and forwards, I’ve included a screenshot for reference.

    The filter is from Caleffi. I am on a private well With hard water and thought it was worth a try.

    I’ve also included a pic of where they originally installed the pump. I thought pumping away was preferred.

    Can anyone point me to a better piping diagram?

    I have cast iron rads each with a TRV, Lochinvar combi unit (it does have an pump in the boiler), Alpha2 pump and manifold. Thank you

  • rick in Alaskarick in Alaska Member Posts: 906
    Unfortunately, you will need to re-do the piping. The picture in the Caleffi manual is for a boiler different then what you have, and can use that piping configuration. Your boiler can't. You need to pull out the manual for the Lochinvar boiler you have and pipe it the way they show it.
  • STEVEusaPASTEVEusaPA Member Posts: 3,481
    edited December 7
    You can also install the manifolds upside down so all your loops can go into the top and you wouldn't need that big down and up loop into the manifolds for the tubing.
  • ZmanZman Member Posts: 5,334
    What model is it?
    Have you looked in the manual?
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • hot_rodhot_rod Member Posts: 12,020
    The icon used in the schematics is also intended to indicate the type of boiler, the pic you show is a cast iron, low or no pressure drop boiler.

    Circulators should always have the motor horizontal.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    The magic is in hydronics, and hydronics is in me
  • mikeg2015mikeg2015 Member Posts: 1,041

    Yup, circulator motor must be horizontal per the manual. You know, tat piece of paper most all contractors throw away because they know it all.

    I double check manuals all the time. Mostly because I’m newer, but also because i can’t remember everything. Taking 5 minute to read and 10 minutes to stop and think and discuss the plan, saves hours of re-work all the time. Just don’t tell my boss that.
  • OhioboilerOhioboiler Member Posts: 3
    edited December 8
    Thank you for this help. Here is the piping diagram from The Lochinvar manual:

    First of all, do I need PRIMARY-SECONDAY PPIPING? I didn’t think it was necessary with a home run system. Am I wrong?

    Second issue is the pump placement. Original install

    I told them to move the pump to supply side, which they did:

    However, I thought the pump should be between the expansion tank and the manifold. Is this correct?

    This is the Noble Combi boiler (with onboard circulator) with Alpha2 pump, manifold and home runs to cast iron radiators each equipped with TRV.

    I will make the necessary corrections myself and have the installers do fill and start up.

    Also, I am so appreciative of this site. I went out of my way to purchase material from the advertisers from this site and Caleffi as a form of thank you

  • GroundUpGroundUp Member Posts: 669
    Yes, you need P/S and yes, the secondary circ should be between the expansion tank and supply manifold
  • DZoroDZoro Member Posts: 934
    Agree with all the above. On the domestic side you also need a T&P valve and a domestic mixing valve.
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