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Question on etc and 0-10 Vdc

clammyclammy Posts: 2,422Member
I see some posts concerning 0 -10 control signal . I have not dug into to deep and most I know could care less but here it goes . Can u use say a ranco etc w a 0 -10 signal out put to control say a variable speed pump or a control valve which would have a fixed set point . Not talking about any type of temp reset just for controlling a set point . I use these instead of aquastat on indirects usually for service and installs and always think what other good can be accomplished w this little device and its control sign hum . Just wondering if anybody out there has looked in other possibilities for applications utilizing its signal output . I always had great luck w etc in refrigeration where they are used a lot but not much on the heating side especially when it’s hydro air .i ve of course seen it used commercial but mostly as on off and not much more . Any thoughts peace and good luck clammy
R.A. Calmbacher L.L.C. HVAC
NJ Master HVAC Lic.
Mahwah, NJ
Specializing in steam and hydronic heating


  • EBEBRATT-EdEBEBRATT-Ed Posts: 6,556Member
    I like the Johnson 350 series. Price isn't bad. The A350P you can get a 0-10 volt signal or a 4-20ma signal or both at the same time.

    You can use them for heating or cooling direct or reverse acting. They have a minimum position set point if you need it. Sensor can be strapped on or put in air or in water with a well. You can also use the A350P to drive other stage modules that have spdt switches and they have a display module to show temp if you want that.

    I have used them to send a signal to drive:
    variable speed drives
    control valves
    damper motors etc

    Don't know if this is what your looking for
  • ratioratio Posts: 2,213Member
    Yes, pretty much anything that puts out a 0-10 (or 4-20 mA) signal can control one. I have had good success with the Honeywell T775 series, albeit not for pump control.
  • EBEBRATT-EdEBEBRATT-Ed Posts: 6,556Member

    I have installed equipment that came with the MH T775. I am not the sharpest knife in the drawer but I just never liked those controls. Just me I guess.
  • ratioratio Posts: 2,213Member
    edited February 2019
    I like 'em a lot. They're programmable enough to do clever things, yet simple enough that it only takes a few times through the manual to figure them out.

    Fer'instance, I used one to stage in a 50 ton condenser & modulate a 1500 MBH burner with room temp reset. I'm pretty sure I could make that system auto changeover too, but I never got the green light from the office.

  • ZmanZman Posts: 5,532Member
    I also find the T775 intuitive and simple. I just finished a hot tub project using a modulating zone valve off of a big boiler system.

    Regardless of brand, 0-10/4-20 mod controlling is with carefully sized valves is the way to go.
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
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