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any HVAC people on here?

Discussion in 'General' started by DBConz, Jan 4, 2023.

  1. socalrider

    socalrider pathetic and rude

    by the way- to the beeb in general, @JBraun and @RonR are both probably way more knowledgeable and experienced in residential AC. I did 18 years in commercial before starting my own residential AC business last year and im learning new things every day.
     
  2. Once a Wanker..

    Once a Wanker.. Always a Wanker!

    socalrider likes this.
  3. Once a Wanker..

    Once a Wanker.. Always a Wanker!

    Add: This house is in Iowa-sota, but I am also needing two new complete heat/AC units at my 32 y.o. GA home, so different environments.
    Hoping insurance comes through for me at the northern house. My general & plumbing contractor found an almost new 65,000 btu Goodman furnace for $500. that he has connected and running in the basement, temporarily.
     
  4. RonR

    RonR Well-Known Member

    Talk to a lot of people in your area to find a highly recommended installer. That is just as important as brand.
    Trane or carrier is our normal go to but that’s like ford Chevy debate. Some love Lennox but it’s way down on my list. Don’t chase seer ratings too high. The payback on some systems is nonexistent. Natural gas is great so just get as high a % as possible on the furnace. As far as nest is concerned I’ve never met one that didn’t need replacing. Good luck
     
    socalrider likes this.
  5. notbostrom

    notbostrom DaveK broke the interwebs

    Unless you have a job. Those credits phase out at double the poverty level so unless you're on food stamps, don't count on any rebate
     
  6. DBConz

    DBConz Registered Idiot

    so i have an installer. i have a fellow racer friend that was suggesting i go for Bosch equipment. i'm sort of asking the forums if there is a recommended brand to request or avoid basically.
     
  7. RonR

    RonR Well-Known Member

    If you trust your installer your work is done.
     
    socalrider likes this.
  8. gt#179

    gt#179 Dirt Dork

    Anyone know a good installer in north GA?
     
    Once a Wanker.. likes this.
  9. Once a Wanker..

    Once a Wanker.. Always a Wanker!

    I have a pretty good Ruud shop that's kept my old stuff working, just south of the big lake. Owner's been in the business locally for a very long time. They may install other products also, I haven't discussed my new stuff with them yet.
     
  10. YamahaRick

    YamahaRick Yamaha Two Stroke Czar

  11. socalrider

    socalrider pathetic and rude

    I believe there could be. From what I have been taught (take with a grain of salt) on a home system your air handler, static pressure within the duct, and total flow volume is designed to run at a set CFM. So if you have 15 vents in your home, (supply diffusers is the trade term) your blower/furnace/air handler really isn't designed for you to have more than one or two of those fully closed and shut. It puts stress on the motor as well as duct seams and joints where transitions from metal to flex occur. So my understanding would be, in a hypothetical scenario you install 15 of those smart vents, and you and your wife spend most of your time in kitchen, TV room, and bedroom, and let's say it shurs of the remaining 10ish vents since no occupancy is noticed in those other rooms where you are not present. It was be stressing your system in the longer term and causing premature death of components. Again, take that with a grain of salt, I'd love to hear a real good answer to the question as well.
     
  12. tony 340

    tony 340 Well-Known Member

    Exact same story happened at my grandmother's old folks home

    Mix in 2 stories, baseboard heaters, and an elevator for the ultimate shitshow
     
    Once a Wanker.. likes this.
  13. pickled egg

    pickled egg Tell me more

    Isn’t that problem cured with variable speed blowers?
     
    YamahaRick likes this.
  14. YamahaRick

    YamahaRick Yamaha Two Stroke Czar

    Wasn't planning to install one - but is putting one in on an existing, older system viable?

    I had planned to only use a few of the "high tech" register covers, as most areas could be controlled by the main thermostat set at a higher temp (summertime). The main objective would be to force more cooled air into certain areas where I would spend most of my time, without having to condition the entire house.

    Granted, my primary objective is to lower bills. I think by switching to a Nights & Weekend rate, that in itself will suffice. Right now I pay about $0.13/kWh; N&W is $0.05. HOWEVER - with N&W, in Jun-Sep, M-F, 4-9PM, it is $0.20. My rough calculations tell me that my bills overall (12 mon period) would drop around 50%. I will study a bit more before making the change, as it is a 12 month commitment.
     
  15. socalrider

    socalrider pathetic and rude

    possibly, but thats not how I understand them to work. the variable speed blower is usually 2 speed, not like a true variable speed that could go up and down from say 10% to 100% in 5% increments. and the two speeds are low and high (again my understanding) so when the unit kicks on and its control board sees a call for 72 degrees, and its reading an indoor temp of 50, it kicks on low speed, calculates time to reach target temp, then kicks on high speed if the time to reach temp is outside of its programmed acceptable range. i could be way off on that. :beer:
     
    YamahaRick likes this.
  16. worthless

    worthless Well-Known Member

    Got it. Thanks!

    BTW, that response reminded me of the scene in Good Will Hunting when he was explaining why he wouldn’t take the job at the NSA.
     
  17. pickled egg

    pickled egg Tell me more

    I’m just spitballing here based on my own knowledge of PLCs and VFDs, but it doesn’t seem like a whole house system utilizing zone controls, multiple temperature sensors, motored supply louvers and stachiometric sensors feeding input to a VFD for the air handler would be *so* difficult to design and maintain.

    Hell, it still pisses me off that your off-the-shelf thermostat doesn’t automagically switch between heat and cool. Setting a delta isn’t fucking rocket surgery. :mad:
     
    YamahaRick likes this.
  18. socalrider

    socalrider pathetic and rude

    totally get you on this. in the commercial world a variable speed drive/PLC or BMS controller works exactly like you are thinking.
     
  19. JBraun

    JBraun Well-Known Member

    Unfortunately it isn't. The equipment isn't nearly as "smart" as it seems.

    The variable speed blower in a furnace is constructed exactly like a three phase motor. Rather than the sine waves creating a rotating field, there's a module connected to it that operates similar to a VFD. They do sense static pressure, but don't actually use static pressure sensors. Instead they cut power to the motor momentarily and record how quickly it slows.

    It's a rudimentary closed-loop system. If the blower wants to produce 1200 CFM, but the ductwork is undersized, the filter is dirty, or it has some goofy zoning system that closes registers, the blower won't get the message. It will keep trying to push 1200 CFM. If the feedback is outside the control's parameters it will default to "high static mode" and simply try to maintain RPM. When that happens, it puts a lot of stress on the module and it eventually fails.

    We change a lot of motor modules, and in every case there's a high static condition caused by dirty filters, a furnace that isn't sized properly for the ductwork, or a retrofit zoning system.

    The only way out is to install a zoning system, furnace, and thermostats that are designed to work together. The only one I have experience with is Bryant's evolution zoning, which gets around the issue by using a modulating or two-stage furnace, and limiting its output to what the open zone(s) can handle. They work but still have limitations. I've also Macguyvered my own versions of this by installing relays that won't allow high stage heat calls unless all zone dampers are open, but that's another can of worms...
     
  20. pickled egg

    pickled egg Tell me more

    Thanks.

    The logic seems simple enough to flowchart, if only I had any time to design or programming knowledge to build.
     

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