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Selecting a Thermostat

Empire_2
Empire_2 Member Posts: 2,343
I was thinking along the lines of a Heat Pump stat. Usually "O" would be energised with a switch to the cool mode. Instead of the rev. solenoid, add a relay to the lo speed fan circuit. Now I don't know if this would be practical but it would work. Just thought I'd throw that out there.

Mike T.

Comments

  • Steve Wilson_3
    Steve Wilson_3 Member Posts: 2
    Selecting a Thermostat

    I have a gas-fired steam boiler in the basement and a air-handler for a/c in the attic. Is there one thermostat that will: a. controll both uses
    b. offer a programable set-back feature
    and as a bonus:
    c. have a low/high blower switch
    Thanks for your help.
  • Empire_2
    Empire_2 Member Posts: 2,343
    Steve, if I may....

    Most digital stats will do exactly as you described with exception on the fan Hi/Lo. Generally when calling for A/C the fan circuit switches into the higher speed mode. This is user selectable in the air handler. I can also add that there are a few more expensive models that will switch your fan circuit to lo when the selector switch is in the cool mode, then switch to hi speed when there is a call for cooling.

    Mike T.
  • carol_3
    carol_3 Member Posts: 397


    I agree with Mike except that I can't think of any stat that lets you select high/lo on the fan. Mike, do you have any specifics?
  • Techman
    Techman Member Posts: 2,144
    Hi Low fan speed

    Hello All .I've had good results by changing the fan rely over to a SPDT style.When FAN switch is in "auto" position andthe t'stat is satisfied than the indoor blower will be on LOW .[fan relay is de-energized].Once the t'stat calls for cooling,than the fan relay is now energized,switching it's contact,and bringing on HI speed
  • Empire_2
    Empire_2 Member Posts: 2,343
    Techman

    I like your thinking, but.......The lo speed would always be on no matter what. I was suggesting that the system switch to cool would energise 1 relay then on a call for A/C the other relay would kick in. This way if the selector switch or system switch is in the off position, the customer can shut down the fan if desired.

    My .02

    Mike T.
  • Techman
    Techman Member Posts: 2,144
    Hi/ Lo Fan Speed.

    HI Mike T. Good thinking to you ,too.Your way requirers that the Lo speed wire [from "o"] , go thru a N.C. contacts of the #2 relay to keep 2 speeds from energizing at the same time. Is that correct ? If so,I like it.
  • Empire_2
    Empire_2 Member Posts: 2,343
    CHeck it out

    This will make more sense.....
  • Empire_2
    Empire_2 Member Posts: 2,343


  • Empire_2
    Empire_2 Member Posts: 2,343
    Check it out

    This is what I was thinking. "O" is energised when the system is set to cooling. "G" will make on a call for cooling giving you hi speed. What's nice is the owner can turn the fan off if he wants by turning system switch to off.
  • Techman
    Techman Member Posts: 2,144
    T'stat

    Mike T. Good idea.Thank's.
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