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My Last Monitor MZ

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Alan (California Radiant) Forbes
Alan (California Radiant) Forbes Member Posts: 4,839
in THE MAIN WALL

Out of 6 we installed between 1999 and 2001, this was the last one that was still in use up until yesterday. They were one of the only decent condensing boilers that were available back then.
We are replacing it with a Viessmann B1HE.

IMG_2088.jpeg IMG_2089.jpeg IMG_2091.jpeg IMG_2095.jpeg
8.33 lbs./gal. x 60 min./hr. x 20°ΔT = 10,000 BTU's/hour

Two btu per sq ft for degree difference for a slab
HVACNUTGGrossHydronicMikePC7060

Comments

  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 20,825

    25 years is a good run for a mod con I guess. Some CI boilers won't do that now.

  • hot_rod
    hot_rod Member Posts: 28,075

    Original expansion tank also?

    Did it develop a leak in the hx?

    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • Alan (California Radiant) Forbes
    Alan (California Radiant) Forbes Member Posts: 4,839
    edited July 16

    Yes, same tank. I never tested the charge. It seems like a benefit to have an on-board x-tank, but you have to drain the boiler to test the charge on the tank. Also, it’s a proprietary part and not something I carry on the truck.

    The boiler was still sound, but the owners are getting older and thought it was time to upgrade.

    Commissioning the Viessmann was all through the app. Even the gas type - this one is propane - is selected on the app. No mechanical adjustment on the gas valve.

    8.33 lbs./gal. x 60 min./hr. x 20°ΔT = 10,000 BTU's/hour

    Two btu per sq ft for degree difference for a slab
    GGrossmattmia2PC7060
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 20,825

    @Alan (California Radiant) Forbes

    So, the owners are getting older and wanted it replaced but you are the same age you were when you installed the old boiler 26 years ago…….Right? LOL😊😊😊😊

    I keep thinking anything installed in the 80s is new equipment to me.

    PC7060
  • mattmia2
    mattmia2 Member Posts: 17,902

    the 70's was 30 years ago, right?

    GGrossPC7060
  • mattmia2
    mattmia2 Member Posts: 17,902
    https://forum.heatinghelp.com/discussion/comment/1900177#Comment_1900177

    but you can plug it and put another tank somewhere else…

  • hot_rod
    hot_rod Member Posts: 28,075

    Put that MZ on e-bay or FB marketplace. Could be a good parts boiler for someone.

    Search MZ here at HH, there have been a few folks looking for a door boiler over the years.

    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
    kcopp
  • Alan (California Radiant) Forbes
    Alan (California Radiant) Forbes Member Posts: 4,839
    edited July 19

    Finished product. We changed the pump to a Grundfos Alpha, added an air eliminator, the expansion tank and gave them a new fill valve. We kept the safety high limit aquastat even though placement is wrong.

    Years ago, the old Monitor MZ boiler was acting up with loss of flame and we found mud wasp nests had clogged the air intake.

    0-24.jpg 0-25.jpg
    8.33 lbs./gal. x 60 min./hr. x 20°ΔT = 10,000 BTU's/hour

    Two btu per sq ft for degree difference for a slab
    PC7060

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