Welcome! Here are the website rules, as well as some tips for using this forum.
Need to contact us? Visit https://heatinghelp.com/contact-us/.
Click here to Find a Contractor in your area.

Uhhh....Which Vaporstat?

Steam_Starter
Steam_Starter Member Posts: 109
in Strictly Steam
Dialing in my single pipe system for the season....got pressuretrol set to 2 psi out, .5 psi in.  However, I want to sensitize the system even further.  Dialed in main venting to about 5.5 CFM on a 45 x 2" run (most I can fit in this joist bay on an antler) and want to keep the pressure low and accurate.



Any suggestions on a good Vaporstat for a Utica Starfire 3 boiler?



Thanks in advance...
"Hey, it looks good on you though..."

Comments

  • Steamhead
    Steamhead Member Posts: 17,314
    The one you want

    is the Honeywell L408J1025. Its range is 0-16 ounces.
    All Steamed Up, Inc.
    Towson, MD, USA
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
    Consulting
  • Steam_Starter
    Steam_Starter Member Posts: 109
    Thanks Steamhead!

    Coming thru for the board, as usual!



    Have a good one...
    "Hey, it looks good on you though..."
  • Alan (California Radiant) Forbes
    Alan (California Radiant) Forbes Member Posts: 4,208
    What's the difference

    between:



    Honeywell L408J1009 and

    Honeywell L408J1025 ??
    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
  • Enreynolds
    Enreynolds Member Posts: 119
    The Honeywell L408J1025 ...

    Makes the circuit on pressure rise only.  The Honeywell L408J1009  will make or break the circuit depending on how it is wired.  For Boiler control, you want to break the circuit on pressure rise to your setpoint.
  • Alan (California Radiant) Forbes
    Alan (California Radiant) Forbes Member Posts: 4,208
    Vaporstats

    So, how would you use the -1025 for boiler control if it makes on pressure rise?
    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
  • Enreynolds
    Enreynolds Member Posts: 119
    The Honeywell L408J1025 ...

    Is set up to be mis-wiring compliant- that is it can only be hooked up one way, which is make on pressure rise.  Honeywell does this by taking a L408J1009, removing the lower (B)  terminal screw and replacing it with epoxy.  I have personal experience with this, as I was offered a L408J1025 at a can't pass up price, when I really needed a L408J1009.  I carefully removed the epoxy from the terminal, ran a tap in it to clean it up, and moved the W terminal screw to the B position.  But I digress.  A L408J1009 is needed for controlling a steam boiler.

    Here is the link to the literature on the L408J series

    https://customer.honeywell.com/resources/Techlit/TechLitDocuments/65-0000s/65-0287.pdf
  • Steamhead
    Steamhead Member Posts: 17,314
    oops..............

    .....................
    All Steamed Up, Inc.
    Towson, MD, USA
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
    Consulting
  • Hap_Hazzard
    Hap_Hazzard Member Posts: 2,846
    Interesting

    Very resourceful solution. I wouldn't have thought that was possible. On the pressuretrols I think they actually remove the terminal from the microswitch.
    Just another DIYer | King of Prussia, PA
    1983(?) Peerless G-561-W-S | 3" drop header, CG400-1090, VXT-24
  • Steam_Starter
    Steam_Starter Member Posts: 109
    Oh Superman...

    Is a Vaporstat Kryptonite for Steamhead?!



    Just kidding...
    "Hey, it looks good on you though..."
  • Steamhead
    Steamhead Member Posts: 17,314
    Nope-

    getting old and working too hard..........
    All Steamed Up, Inc.
    Towson, MD, USA
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
    Consulting
  • Hap_Hazzard
    Hap_Hazzard Member Posts: 2,846
    Better than the alternatives.

    ;-)
    Just another DIYer | King of Prussia, PA
    1983(?) Peerless G-561-W-S | 3" drop header, CG400-1090, VXT-24
  • voice3
    voice3 Member Posts: 2
    Follow-up two-wire vaporstat question

    I'm also looking to replace a Honeywell 404a pressuretrol on a one-pipe steam system with a vaporstat. However, I can't find a two-wire vaporstat for steam. Does one exist?
  • Enreynolds
    Enreynolds Member Posts: 119
    Vaporstat

     The Honeywell L408J1009  will make or break the circuit depending on how it is wired.  For Boiler control, you want to break the circuit on pressure rise to your setpoint. You would wire this with one wire to the top terminal and one to the bottom terminal.  The vaporstat acts as a simple switch in the circuit, either allowing current to pass or not, depending  on the pressure.

    Eric
  • voice3
    voice3 Member Posts: 2
    edited November 2012
    Two-wire setup

    Thanks Eric. That's exactly what I needed to know.
This discussion has been closed.

Categories