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HTP Versa Hydro 0-10v input

Turbo DaveTurbo Dave Member Posts: 66
Hello to all. Have any of you connected 0-10v control to an HTP Versa Hydro? If so, I need assistance with programming. The installation manual does not explain how to enable the external input. It does have a "Mod-bus" function, but I am simply connecting to a Tekmar control with EMS 0-10v output. Thanks.


  • mattmia2mattmia2 Member Posts: 2,297
    In a UFT it i always on, it just takes anything over 1.5 v as a heat call and modulates between the min and max water temp setting based on the voltage between 0 and 10. In the UFT manual it is explained in the fine print around where it explains step modulation.

    There is someone from HTP on here and if you e-mail HTP's support they are good with answering question like that.
    Turbo Dave
  • ZmanZman Member Posts: 6,315
    Have you looked at the instructions on page 30?
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
    mattmia2Turbo Dave
  • Turbo DaveTurbo Dave Member Posts: 66
    This an older unit. However, since this post I see that the printed installation manual is different than the downloaded version. On page 33, the instructions appear. They left those out of the original printing! Thanks for your quick response!
  • Turbo DaveTurbo Dave Member Posts: 66
    edited January 2020
    Update: The boiler control does not accept the input code in the manual. I called HTP tech support early last week. They said the unit doesn't offer 0-10v input capability. I pointed out the installation manual, wiring diagram, and terminal board all show 0-10v input. I received this in an email:

    "We will have to verify with engineering, there may be an issue with the installation manual. However receiving the correct information will not be fast. When we have received the answer we will respond back to you."

    My customer would love me to be completely finished with this job. Hopefully I can report back with the solution soon.
  • mattmia2mattmia2 Member Posts: 2,297
    So this is a change to a system that was installed over 3 years ago?
  • Turbo DaveTurbo Dave Member Posts: 66
    edited January 2020
    Yes. The installing contractor and homeowner have been in dispute since then, regarding cold rooms, excessive fuel consumption and PRV blow-off at the aux. heat source. Among piping, pumping and other changes, I installed Tekmar controls. When planning this job, I researched that the boiler accepted 0-10v input for external temperature control. It's in the installation instructions, shown in the wiring diagram, and on the terminal board of the boiler. All I need now is the correct code to enable the option. I am surprised that I seem to be the first contractor to ask HTP how to use this feature of a boiler that has been on the market for a long time.
  • Turbo DaveTurbo Dave Member Posts: 66
    Final word from HTP: Boiler does not have 0-10v input capability, even though the installation manual, terminal strip and wiring diagram all show it. Surprising news, to say the least. Bummer.

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