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Replace low hanging black steel pipes with Pex tubing in homerun config to radiators?

Input anybody? We are trying to make the "right decision". 1936 home. just removed original converted coal to natural gas boiler and expansion tank. The radiator heat system has been awesome for34 years we have lived here. We will be installing a high efficiency gas fired condensing boiler plus a few heat pumps for some a/c next year. 100% asbestos abatement just done. The basement pipes are freshly painted with all asbestos removed. Hubby wants the small gain of ceiling space with a spaghetti dinner of Pex. Wife is conservative and old fashioned, energy conscious. Worried that this might compromise the formerly perfect radiator system. Pex or original piping to the radiators above? Save a marriage!


  • Steamhead
    Steamhead Member Posts: 16,234
    Not to mention the cost. Leave the pipes as they are, and insulate them with fiberglass.
    All Steamed Up, Inc.
    Towson, MD, USA
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
  • hot_rod
    hot_rod Member Posts: 19,854
    If you are talking a pex system homerun, 3/8 & 1/2" pex is workable. Possibly several radiators on one set of pex.

    If you are up for it, the tubes could be drilled thru the joists and be covered with a ceiling

    Refer to a joist drilling schedule for spacing of holes.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
    Project42dayAlan (California Radiant) Forbes
  • leonz
    leonz Member Posts: 840
    Please show us a picture of the boiler and piping at the boiler.

    What Jamie and Steamhead said, leave it as is and insulate the pipes or just leave them exposed as the basement and floor above the piping will be warmer.
    If you have standing column radiators as it appears from the basement view using pex to replace the existing pipe will be a waste of time and your good money.

  • hot_rod
    hot_rod Member Posts: 19,854
    I suppose if one goal is to finish the basement for additional living space, which increases the value and resale value, it may be worth moving pex lines into joist space. Walls are insulated and furred, you are part way there :)

    Looks to me you gain at least 6" in some areas?

    Have you priced fiberglass insulation for all those lines$? Insulation boots for the ells and tees?
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • Project42day
    Project42day Member Posts: 3
    Update, the wife won! We are keeping the black steel pipe for the new installation. That also gives us $ 12,000.00 for other projects and warm floors on the main floor. We will determine what (or if) to wrap them with during this first heating season. The pipes will remain as a quirky old house feature in the basement family viewing room we envision. I will report back to this thread when the cold weather arrives and the new boiler system is installed. Had there been any problems with the original system we might have been more open to further change with PEX. Imagine for 34 years, annual inspection and not a single problem with a cosy, totally silent, balanced, gravity fed system! Fingers crossed the new boiler will live up to the original. We are in Niagara Region in Canada and tried all summer to secure an LG trained technician to install an LG Multi VS with Hydro Kit so we could say goodbye to Natural Gas. We worked with the main LG supplier for our area (O'Dell Associates) to find a qualified tech to do the job, to no avail. We had technicians not even show up, "ghost" us, or back away (due to so many lucrative new multiunit residential and commercial projects). Winter is coming, We gave up and will remain with a new IBC SL 14-115G3NG natural gas boiler with an indirect hot water tank. We'll do the ductless heat pump/minisplits for a/c next year. That will give us some "shoulder season" heating flexibility as well. Thanks to all who posted replies.
  • SuperJ
    SuperJ Member Posts: 606
    edited September 18
    IMHO you made a good call. Good heat pump technology does exist (popular in Europe). But in NA equipment and contractor options are limited. In another 5-10years I suspect the landscape will have changed. Residential mech systems are too much of an investment to be an early adopter and be plagued with long standing issues.
    Re the LG HP, you could contact GPA in Toronto https://gpainc.ca/ (Distributor not dealer for LG). They may recommend a dealer. I've worked with them commercially (I work for a commercial controls contractor). But, I think you'll have a better heat pump experience in a couple years.
  • Teemok
    Teemok Member, Email Confirmation Posts: 52
    Good boiler choice. A secondary reason to re-pipe would be new zoning. I might have considered running individual radiator supply and returns or group zoned reverse return branches of pex-al-pex (not floppy and expands similar to copper) routed above the ceiling back to a manifold circulated by an ecm secondary pump. If sized correctly you would never know the difference performance wise and if flows were balanced right with outdoor reset and start boost used you might get better efficiency and responds times. I do like to see the old pipes still doing their thing though.
  • hot_rod
    hot_rod Member Posts: 19,854
    In addition to picking up more user friendly basement space.
    A home run system could provide room by room zoning with TRV or actuators on the manifold. A 37W ECM circ would cut power and probably heating costs by zoning the system.

    With a mod con you could ship the mix valve shown in this example.
    Just saying.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream