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  1. #27
    Join Date
    Mar 2013
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    Treasure coast, FL
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    Quote Originally Posted by Poodle Head Mikey View Post
    I would use the method you mention to do the stage cycling. But I would also want to alter the lead/lag order as well / switch the stages: one for the other.

    Because if the 33% was always stage one - at some point the larger 66% would be cycling on and off to maintain the set point.

    So, to minimize that, above some 'to be determined' outdoor ambient, I would want the 66% to lead - with the 33% cycling to maintain the setpoint.

    PHM
    ----------
    How about:

    3 stage cooling.

    1st stage is the smaller, 33 percent compressor.

    2nd stage activates larger 66 percent compressor as well as a relay where the small compressor contactor control voltage is run through the N/C contacts of it, meaning on a call for second stage cooling only the 66 percent compressor will run.

    3rd stage will activate both compressors by using a relay that bypasses the 2nd stage " lockout" relay, which would still be

    You'd have to get a Honeywell T350 or some other more-than-two-cooling-stages thermostat but it sounds potentially simpler than involving an outdoor reset that swaps your lead/lag stages.

    Sent from my Moto Z (2) using Tapatalk

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  3. #28
    Join Date
    Sep 2002
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    27,400
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    That's a good idea - I hadn't considered using a three stage thermostat.

    I used to set up boilers the way I described. On larger houses where there was enough load to make two boilers worthwhile.

    Although, on anything above a very basic level I expect that 'the next guy' just jumps everything out to make it all run together anyway.

    PHM
    --------


    Quote Originally Posted by shellkamp View Post
    How about:

    3 stage cooling.

    1st stage is the smaller, 33 percent compressor.

    2nd stage activates larger 66 percent compressor as well as a relay where the small compressor contactor control voltage is run through the N/C contacts of it, meaning on a call for second stage cooling only the 66 percent compressor will run.

    3rd stage will activate both compressors by using a relay that bypasses the 2nd stage " lockout" relay, which would still be

    You'd have to get a Honeywell T350 or some other more-than-two-cooling-stages thermostat but it sounds potentially simpler than involving an outdoor reset that swaps your lead/lag stages.

    Sent from my Moto Z (2) using Tapatalk
    PHM
    --------
    The conventional view serves to protect us from the painful job of thinking.

  4. #29
    Join Date
    Apr 2020
    Location
    Garner NC
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    534
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    i did work for a place that used the 2 stage but has the refrigerant solar panels coming off the condenser then into the AH coil... very expensive. it was supposed to run making it have a seer rating of 45. the math was never provided to me. i never saw it run in 2nd stage..but thats what they said made it efficient..
    i was not at a tech level yet...only install

  5. #30
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    Apr 2020
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    Garner NC
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    i remember as a child, a relatives home had a huge 3' fan in the attic, if it got too hot you open the bottom floor windows opened the attic door and hit the switch...that was "real" air conditioning...i still remember the roar of it...massive airflow, lol

  6. #31
    Join Date
    Sep 2005
    Location
    Atlanta GA area
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    44,275
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    Quote Originally Posted by Unlimited1 View Post
    i remember as a child, a relatives home had a huge 3' fan in the attic, if it got too hot you open the bottom floor windows opened the attic door and hit the switch...that was "real" air conditioning...i still remember the roar of it...massive airflow, lol
    Yeah... those were called 'attic fans' when I was a kid (back in the dark ages)...
    Ran it in the early morning and as the sun went down.

    Now they are called 'whole house fans'... are 24-30" dia... move about 1/3 to 1/2 the air... and builders do not include them in a house.

    I have taken many an old fan, built a box around it, and used it to keep the air stirred up where I was working.

    Picked up one from the side of the road a month ago... gonna build that one for my shop...
    GA-HVAC-Tech

    Your comfort, Your way, Everyday!

    GA's basic rules of home heating and AC upgrades:
    *Installation is more important than the brand of equipment
    *The duct system keeps the house comfortable; the equipment only heats and cools (and dehumidifies)
    *Cheap is not good, good is not cheap; however expensive is not a guarantee of quality!
    Choose your contractor wisely!

  7. #32
    Join Date
    Sep 2002
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    One time I was doing some work for the US Navy in a gigantic (former) airplane hanger / test area. While on site another company was tearing down some offices in the same space. The offices had been heated with a large steam coil up hear the ceiling with a 12" turbo-axial fan blowing air down to the offices.

    The fan was laying in a pile pf debris and they said I would have it. I only wanted because it was so industrial-cool looking. <g>

    My house had no AC at the time and one hot day I happened to see that axial fan and thought: Whole House Fan!

    It had come home with a short piece of really heavy gauge round duct flanged onto it. I hauled it up to the attic and hung it up under the ridge beam - slung from ropes. <g> The discharge end of the round duct was flush against the screen on the gable-end-vent.

    It vaguely strikes me now that it was 460V or maybe 3 phase and I had to install a 120V motor but I'm not sure. Anyway; I get it hung and set the belt tension and so forth. Then I start it going. It's like a friggin Wind Tunnel in the attic and when I get downstairs it is making a pretty stiff breeze though the house. It was loud in the attic but can only hear the slightest hum from it running downstairs.

    It's been a hot sweaty bastard in the attic so I go outside - the sun is setting and it's cooling off outside. That house is on a corner. Out front I see my oil burner guy neighbor Mike - he smoked a pipe and would often walk around with it.

    Hey Mike! Just trying to wear those shoes out or what?

    Yeah I guess so. Can you hear that noise?

    No; what noise?

    So Mike comes across the street and in front of my house we listen. He says; Damn - I don't hear it now.

    What did it sound like? I've been here all day - I didn't hear anything.

    I don't know . . . maybe like a helicopter or something? Like a weird howling noise almost? I can't describe it. At first I thought it Was a helicopter hovering - that's why I came out to look.

    So Mike and I walk down to the corner and he says: Now I hear it - where the hell is that coming from?

    I have already heard the weird noise and I'm trying to get a bearing on it. Mike and I walk around and listen and the sound seems to be coming from everywhere - from every direction. The neighbor from right across the street from the end of the house comes out: What are you guys doing?

    Can't you hear that noise? Where is that coming from?

    I hear it now - what is it?

    Damn if I know; we're trying to figure it out - I never heard it before.

    In a minute or so his wife comes out to see what we're all doing. And then joins us: "What is That???"

    After several minutes the light goes on in my tired head. "I'm thirsty - I'll be right back . . . you all want anything?" and I head inside. I race upstairs and pull the plug. Downstairs, grab some iced tea, and head back out.

    Figure it out yet?

    No; but we can't hear it now. It just stopped.

    Stopped? How can that be? Where was it coming from anyway?

    Of course nobody knows, we all puzzle over it for a bit, and then each wander away.

    So the 'whole house' fan worked great - just couldn't use it. <g> Inside the house it was fine - but it kind of 'projected' it's operating noise out with the airflow. I resolved to change the sheaves (the blade ran at motor speed or maybe slightly higher - I forget which sheave was slightly larger than the other) to reduce the noise but pretty soon after that I got pissed off at the oil furnace clogging nozzles every three days and ripped it all out to install new Coleman 'super high efficiency' (13.1 SEER <g>) cooling and a 'super high efficiency' (91% <g>) gas furnace.

    And that was the end of my Whole House Fan use. <g>

    PHM
    ----------


    Quote Originally Posted by ga-hvac-tech View Post
    Yeah... those were called 'attic fans' when I was a kid (back in the dark ages)...
    Ran it in the early morning and as the sun went down.

    Now they are called 'whole house fans'... are 24-30" dia... move about 1/3 to 1/2 the air... and builders do not include them in a house.

    I have taken many an old fan, built a box around it, and used it to keep the air stirred up where I was working.

    Picked up one from the side of the road a month ago... gonna build that one for my shop...
    PHM
    --------
    The conventional view serves to protect us from the painful job of thinking.

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