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Replacing old modulating valves

SeanBeans Member Posts: 520
edited November 2019 in Strictly Steam
I have a system where a number of the B&B valves are leaking from the stem.

I read the article in the library on the Bishop & Babcock system and it states that they are a packless valve.

What are my replacement options? Would like to stay with a modulating valve like what is there now but I know that may not be possible.

Attached a photo of the valve. I’m not sure I have a full photo


  • Jamie Hall
    Jamie Hall Member Posts: 23,272
    I suspect that a Hoffman 185C might be a decent replacement if you can't get those to stop leaking. Trouble is, they aren't cheap.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • SeanBeans
    SeanBeans Member Posts: 520
    I would like them to to stop leaking, problem is I don’t know how. Never ran into a packless valve.

    Looks like the 185c is what I need, thanks.
  • Steamhead
    Steamhead Member Posts: 16,823
    All Steamed Up, Inc.
    Towson, MD, USA
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
  • Jolly Bodger
    Jolly Bodger Member Posts: 209
    Reading the Lit it looks like they used a bellows to seal the stem. my guess is this is cracked. Parts probably not available. You would have to take one apart but I wonder if a machine shop could grove it for an o-ring on the stem.
  • Gordo
    Gordo Member Posts: 857
    @SeanBeans : You might want to consider getting a "MAC-RSBB 75-VA" Bishop & Babcock valve rebuild kit from Tunstall. You essentially remove the guts of the valve and thread in their kit. No, it might not have that early 20th century charm, but it will fix the leak and allow a TRV actuator to be installed should you so chose. It will also allow you to fix the leak without disconnecting the radiator and removing the old spud, which can be a plus.
    All Steamed Up, Inc.
    "Reducing our country's energy consumption, one system at a time"
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
    Baltimore, MD (USA) and consulting anywhere.
  • Dave in QCA
    Dave in QCA Member Posts: 1,785
    I have successfully cleaned up an old packless valve several years ago. It worked very roughly, bound up, got stuck, etc. All I did was remove the top of the valve body and disassemble the parts. I cleaned lime residue with Limeaway and 0000 steal wool. After thoroughly rinsing and drying, I put a small amount of high temperature grease on the mating seal parts and the stem threads. When I reassemble it, it worked great. I installed it on a hot water system and had no leaks whatsoever.
    Dave in Quad Cities, America
    Weil-McLain 680 with Riello 2-stage burner, December 2012. Firing rate=375MBH Low, 690MBH Hi.
    System = Early Dunham 2-pipe Vacuo-Vapor (inlet and outlet both at bottom of radiators) Traps are Dunham #2 rebuilt w. Barnes-Jones Cage Units, Dunham-Bush 1E, Mepco 1E, and Armstrong TS-2. All valves haveTunstall orifices sized at 8 oz.
    Current connected load EDR= 1,259 sq ft, Original system EDR = 2,100 sq ft Vaporstat, 13 oz cutout, 4 oz cutin - Temp. control Tekmar 279.