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#1 Hoffman differential loop

gerry gill
gerry gill Member Posts: 3,078
above the waterline should be at least 24'' measured from the top of the differential loop down to the waterline..not sure if the old installation actually had that.. sounds like you'll be fine as long as your still covering all your wet returns appropriately..the info is from page 203 of the 1935 hoffman data book..i think the 1928 edition is in Dan's library section..post some pictures when your done..i don't get to see to many hoffman systems in my neck of the woods.

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  • FRANK_24
    FRANK_24 Member Posts: 80
    #1 hoffman differential loop

    I sold a Peerless gas steam boiler which has a water line @ 25 7/8" . The old boiler, an origionally coal fired snowman has a water line of 50 1/2", with a #1 Hoffman differential loop installed with the bottom part of the assembly at 50 1/2". Do I need to maintain the origional water line, i.e. raise up the boiler or what???
  • Jamie Hall
    Jamie Hall Member Posts: 23,286
    You should be fine

    provided, as Gerry says, you make sure all your wet returns are covered, particularly at the far ends of the lines. You may find the odd drip at a remarkably high elevation...

    The differential loop itself works dandy, provided it is high enough.

    Oh yeah. Also -- the differential loop works dandy, provided the pressure is low enough. Use a vaporstat.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
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