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New circulator/REAL old system

GordonIsland Member Posts: 2
Hi all,

I’m working in my 130 yr old home, which is still using much of its original heating system; huge kewanee boiler (converted to gas,) hot water radiators on two floors (covering 3000 sq ft,) and B&G pump- I believe an old HV. 

Recently a leak at the circulator worsened, and seized the bearing. I called around to B&G and Taco, settled on a taco brg-b-101 bearing assembly. It fit the pump, but not the motor-I’m thinking now that taco bearing assembly should’ve been brg-b-100. 

I’m going to replace the motor now too, being the original has had water running through it the past few years...

Seems for $400 I can stick with taco, and get the motor meant for the 101 bearing assembly, mot-b-101s, which also appears to be a replacement for the B&G HV “new,” 111061, or go with the B&G motor, OR i can get an entire replacement pump, changing everything between the flanges for $800

Are any of these options better than another? Or is there a better option I’m not aware of. I’m hoping to sell the house next fall, I just want heat for my family right now. 

Not 100% sure what pump it currently is, but it’s 8-1/2” flange to flange, 4-bolt flanges, attaching to 2” pipes. 

Thanks ahead of time. 


  • Steamhead
    Steamhead Member Posts: 16,823
    That's probably what B&G calls a 2-inch circulator. Info on your current circ is here, along with a list of replacement parts:


    If it were my house, I'd go with a more-modern wet-rotor circulator that has similar flanges. This Grundfos model looks like a good replacement. It does not have the mechanical seal that failed on yours:

    All Steamed Up, Inc.
    Towson, MD, USA
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
  • Robert_25
    Robert_25 Member Posts: 527
    edited January 2021
    That seems like a huge circulator for a 3000 sq ft house.  I would want to know more about the heating system before choosing a replacement.  You may be able to use a smaller and less expensive wet rotor circulator.
  • hot_rod
    hot_rod Member Posts: 22,105
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • mattmia2
    mattmia2 Member Posts: 9,622
    well, the fact that they spray painted it gold...
  • GordonIsland
    GordonIsland Member Posts: 2
    Steamhead, the B&G pump you listed is the “modern” equivalent of what’s in there. My only reservation (aside from cost) is removing what seems to be a perfectly functional pump; I don’t know how the flange bolts will react, there’s old pipes on either side of the flanges, and if I don’t have to open a potential can of worms, then I’d rather not. Which is why I’m leaning toward just replacing the motor. 

    Robert_25, the house is actually 4500, not counting the basement, but a separate pump takes care of the 3rd floor loop. 

    The circulator in question serves 17 cast iron radiators between the first two floors, and one on the 3rd. There were a few others up there, but they were removed and the lines capped off before we got the house. I think the lines are 3/4” between them (the ones I redid in the kitchen a few years ago definitely are.)
  • Ironman
    Ironman Member Posts: 7,373
    If the 3,000 sq. ft. portion of your house envelope is old and very leaky, you may need 35 btus per square foot to heat it on the coldest night of the year. That’s 105k btus or slightly over 10 gpm. With old large gravity piping, the system would have 5 feet of head maximum. A small wet rotor circ like a Grundfos ups15-58 would be more than capable of handling that.

    Of course, that would require replacing the pump flanges (preferably with iso flanges) and draining and refilling the system. Something that may be better suited to do when the heating season is over.
    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.