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  1. #1
    Join Date
    Apr 2005
    Posts
    104
    Hey Gang, A friend of mine was wanting to purchase an thermo-stat with Auto-changeover. Can this type of stat be purchased off the shelf from local retail stores (e.g. Home Depot)?
    Thanks.

  2. #2
    Join Date
    Jun 2004
    Location
    Clayton,NC
    Posts
    407
    Ummm we really don't have a lot of info on what home depot has in stock. I dont think they have anyone quialified to tell you what will work with your system and what won't. I think an auot change over is a good idea. Here in the NC we need heat in the mornings and cooling in the afternoon several months a year. I would like to warn you that many T-stats are made for specific systems ( heatpump,electric,gas) and the wrong type stat can cause larger problems.

    Please take a look here.

    http://hvac-talk.com/vbb/showthread.php?threadid=76850

  3. #3
    Join Date
    Mar 2005
    Location
    Indianapolis, IN
    Posts
    241
    Get VisionPro 8320 or 8321.


  4. #4
    Join Date
    Apr 2005
    Location
    Tampa, Florida
    Posts
    1,634
    I can't think of any consumer-grade stats which have auto-changeover. That feature used to be strictly found on commercial thermostats but now has found its way onto the stats sold by contractors. I guess they consider it to be a "premium" feature and save it for the pro stats. Very worthwhile feature in climates with huge temp swings on in moderate climates where both heating and cooling are needed in the same day.

  5. #5
    Join Date
    Aug 2003
    Location
    Fort Worth, TX
    Posts
    11,289
    Main advantage of auto changeover stats in resi applications is, if the deadband is set right, homeowner doesn't have to worry about manually shifting between heating or cooling. In my own climate at certain times of the year it can be warm and humid during the day, requiring a/c, and a "blue norther" blows through in the evening, dropping temperatures overnight to where the house would be chilly if the heat didn't come on. I've also lived in arid climates where in winter the night temps were in the thirties and the day temps pushed into the eighties, perfect for auto changeover.

    Far as I know, auto changeover stats have been available at parts houses for years, meaning any contractor could've bought one and stuck it into a resi app at any time if he so desired. I think with the advent of everything going digital, and the concurrent feature-laden approach taken to sell this stuff, more homeowners are wanting to see this kind of control at home.

    I also don't think you'll find auto changeover stats at Home Depot. Thank goodness...hard enough for DIY'ers to change a stat without blowing a fuse or xformer...sure would hate to see a handsome stat like the 8321 go up in smoke.
    • Electricity makes refrigeration happen.
    • Refrigeration makes the HVAC psychrometric process happen.
    • HVAC pyschrometrics is what makes indoor human comfort happen...IF the ducts AND the building envelope cooperate.


    A building is NOT beautiful unless it is also comfortable.

  6. #6
    Join Date
    Apr 2005
    Posts
    104
    Excellent info! Thank you!

    Yes, the wide temperature swings is exactly the case for the where the house is located: cool in the morning, hot in the afternoon.

    The furnace/a-c system is a Lennox system. I will ask a local Lennox rep for a stat.

    Thanks again.

  7. #7
    Join Date
    Oct 2001
    Posts
    6,942
    all solid state stats are auto changeover...off/heat/cool/ auto,fan would be on/auto...put "thermostat" in http://www.homedepot.com search

    [Edited by maxster on 05-28-2005 at 01:20 PM]
    "when in doubt...jump it out" http://www.youtube.com/watch?v=U1qEZHhJubY

  8. #8
    Join Date
    Apr 2005
    Location
    Tampa, Florida
    Posts
    1,634
    Shophound: Yep, they've been around forever, seen (and replaced) plenty of the old mechanical Honeywell auto-changeover stats. (guessing they came out in the 60's? well before my time) It's much simpler now with the better digital stats where a few extra lines of software code can handle it. As to why it's taken so long for it to show up in residential settings, I think primarily is because consumers don't want to spend $$$ for a thermostat when they're used to a cheap old mercury stat on the wall. I also think contractors are a bit worried that some of their customers wouldn't understand the idea of two setpoints. To those who think this isn't that common or think I'm just consumer-bashing, I had a no-cooling call this week from my own parents. The system was fine, but you're never going to get the AC on by adjusting the heat setpoint (WR 1F95-371 stat)


    Originally posted by maxster
    all solid state stats are auto changeover...off/heat/cool/ auto,fan would be on/auto...


    Oh really? I think it's safe to say that most digital stats are not auto-changeover, especially at the lower-end of things (HD/Lowes/etc). After looking over at HD's site, I see why I end up replacing so many Hunter,Lux,RiteTemp stats -- the price. If those stats were priced at what a decent digital stat (WR/Honeywell/Robertshaw..well maybe scratch that last one) is, people wouldn't be so eager to install a thermostat on their own. The low prices also explain the high failure rates as well.

  9. #9
    Join Date
    Aug 2003
    Location
    Fort Worth, TX
    Posts
    11,289
    Originally posted by tpa-fl
    Shophound: Yep, they've been around forever, seen (and replaced) plenty of the old mechanical Honeywell auto-changeover stats. (guessing they came out in the 60's? well before my time) It's much simpler now with the better digital stats where a few extra lines of software code can handle it. As to why it's taken so long for it to show up in residential settings, I think primarily is because consumers don't want to spend $$$ for a thermostat when they're used to a cheap old mercury stat on the wall. I also think contractors are a bit worried that some of their customers wouldn't understand the idea of two setpoints. To those who think this isn't that common or think I'm just consumer-bashing, I had a no-cooling call this week from my own parents. The system was fine, but you're never going to get the AC on by adjusting the heat setpoint (WR 1F95-371 stat)
    I got a box full of the mechanical Honeywell auto changeover stats at work. They were replaced by VisionPro 8320's. The old stats got mercury bulbs in them and I just can't bring myself to chunk them into the dumpster, addding mercury hazardous waste to the landfill. Anybody want some mechanical auto changeover stats?

    I do think there's a growing market for feature hungry homeowners who aren't afraid of technology and would like auto changeover features on a thermostat such as the VisionPro. Neat thing about that stat is the installer can set the temperature parameters and deadband to minimize chances the occupant might run the temp up too high or too low, resulting in a nuisance service call. Also has the optional outdoor sensor or remote indoor sensor and humidistat.

    In my own home I run a VP with auto changeover enabled and we never worry about "did we forget to turn the furnace on" when a norther blows through or arriving home to a hot house after a day that got much warmer than expected. With the setback features I wake up to a warm house in winter and come home from work to a cool house in summer, but when we're asleep or not there, the stat is saving us money.

    Since installing it and upgrading our insulation last fall, our winter nat. gas bills were almost half of the previous heating season, which was very similar to this past winter's demands. We're just getting into cooling season here but already I can see the system doesn't work as hard on hot days and the humidity control is much better since I tweaked the system.
    • Electricity makes refrigeration happen.
    • Refrigeration makes the HVAC psychrometric process happen.
    • HVAC pyschrometrics is what makes indoor human comfort happen...IF the ducts AND the building envelope cooperate.


    A building is NOT beautiful unless it is also comfortable.

  10. #10
    Join Date
    Apr 2005
    Posts
    104
    Thanks again for the info...I did check out HD, and unfortunately, the t'stats offered do not have auto-changeover. So, to get a VP stat, I would need to go online, or go to a local rep to pick one up.
    Cheers.

  11. #11
    Join Date
    Apr 2005
    Posts
    104
    ...I take that back I think the HW stat offered at HD is HEAT-OFF-COOL-AUTO, with FAN ON/AUTO switch as well...going to check it out. Thanks gang.

  12. #12
    Join Date
    Jan 2005
    Posts
    340
    Originally posted by shophound
    I got a box full of the mechanical Honeywell auto changeover stats at work. They were replaced by VisionPro 8320's. The old stats got mercury bulbs in them and I just can't bring myself to chunk them into the dumpster, addding mercury hazardous waste to the landfill. Anybody want some mechanical auto changeover stats?
    Check and see if you've got a local distributor that participates in the TRC program.

    http://www.nema.org/gov/ehs/trc/

  13. #13
    Join Date
    Aug 2003
    Location
    Fort Worth, TX
    Posts
    11,289
    Good info, travis, thanks!

    • Electricity makes refrigeration happen.
    • Refrigeration makes the HVAC psychrometric process happen.
    • HVAC pyschrometrics is what makes indoor human comfort happen...IF the ducts AND the building envelope cooperate.


    A building is NOT beautiful unless it is also comfortable.

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