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Hoffman Temperature Controller C-93

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nz
nz Member Posts: 125
Anyone know what this is? Is it a primitive aquastat? 

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  • pedmec
    pedmec Member Posts: 994
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    judging by the wiring diagram it looks like an outdoor air temperature sensor, its just pneumatic. outdoor air temperature drops below the target temperature and it kicks the circulator on to start heating the building. similar to a honeywell 4006 with 25' element. just an educated guess.
  • mattmia2
    mattmia2 Member Posts: 9,850
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    Where do the capillary tubes go? It looks like the right bellows first tips the big lever and starts the circulator on boiler temp rise and ans temp continues to rise cuts the burner on high limit and the left bellows cuts the circulator if return water temp falls too low.

    Whatever you do, dont adjust anything in there unless you find instructions.
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 15,767
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    Ther is no electrical input to start the control. The left hand capillary whatever it senses starts the circulator and powers the transformer which controls a valve depending on the temperature of the right hand capillary
  • pedmec
    pedmec Member Posts: 994
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    the right side looks like its connected to the lugs on top and the left side is connected to the microswitch on the left bottom.
  • nz
    nz Member Posts: 125
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    mattmia2 said:
    Where do the capillary tubes go? It looks like the right bellows first tips the big lever and starts the circulator on boiler temp rise and ans temp continues to rise cuts the burner on high limit and the left bellows cuts the circulator if return water temp falls too low. Whatever you do, dont adjust anything in there unless you find instructions.
    One of the capillary tubes connects to the hot water supply from the boiler, right before it branches into the four zones. 

    The other goes into the plaster, I can't see where it goes. I'm guessing it's not in use it doesn't work anymore, I've never heard it do anything or seen the lever move.

    Do you think I can rip it out? I am planning to install a tekmar 260 and a 305p in the near future. 

  • reggi
    reggi Member Posts: 522
    edited October 2022
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    This should answer all your questions...or at least someone should be able determine what if anything should be ripped out or modified. ..

    Right here all the time 👍 @DanHolohan @Erin Holohan Haskell (Maybe Erin can clean up the link ? )

    One way to get familiar something you know nothing about is to ask a really smart person a really stupid question
    mattmia2
  • Erin Holohan Haskell
    Erin Holohan Haskell Member, Moderator, Administrator Posts: 2,335
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    reggi said:

    @Erin Holohan Haskell (Maybe Erin can clean up the link ? )



    Yes, I cleaned up the links above. Thanks.

    President
    HeatingHelp.com

    reggi