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  1. #1

    Unhappy

    I just had a Amana AMV9 2 stage varible speed furnace installed today. All the work looks very well done except they installed a single stage thermostat. Doesn't this defeat the purpose of the 2 stage furance?? I wasn't here when the tech finish the installation and my wife had no idea was to look for. The salesman didn't give me any thermostat choices when I got the estimate. Should I request that they install a 2 stage thermostat??

  2. #2
    Join Date
    Nov 2005
    Location
    Charlotte, N.C.
    Posts
    964
    Yea I would say that probably defeat the purpose. Get a 2 stage stat.

    >>>edit... removed caps


    [Edited by jultzya on 11-09-2005 at 10:05 PM]

  3. #3
    Join Date
    Jun 2002
    Location
    Bemidji, Mn
    Posts
    3,573
    Some units go to second stage via the control board too, depends on what you have. What Im saying here is your 2 stage furnace will still work in many cases.Not sure on that brands specs.
    You picked a fine time to leave me loose wheel...

    http://rapalaguy.spaces.live.com/

  4. #4
    I read the owners manual and it states that you can use a single stage thermostat, It will will be on low stage for 5-10 min depending on the DIP switch settings. I think they should have at least offered or told me which type thermostat they were going to install. Do you have to add extra wiring for a 2 stage thermostat?? The old furnace was installed in the 70's...

  5. #5
    Join Date
    Nov 2005
    Location
    Charlotte, N.C.
    Posts
    964
    Yea some do go to second stage after X amount of run time based on unit, I’m a Trane guy so I’m not 100% sure but I don’t think that furnace does.

    >>>edit... removed caps


    [Edited by jultzya on 11-09-2005 at 10:07 PM]

  6. #6
    Join Date
    Jun 2004
    Location
    St Paul, minnesota
    Posts
    1,211
    yes you need an xtra wire for a 2 stage stat. That's probably one reason why they didn't offer it. Single stage stat will be fine as that furnace does have a timer in it that will bring on the second stage after 5-10 minutes of operation on 1st stage. If your furnace is sized right (by using the manual J) a 2 stage stat is unnessary.

  7. #7
    Join Date
    May 2000
    Location
    Indianapolis, IN, USA
    Posts
    34,171
    horsehockey

    Regardless of sizing, get a 2 stage stat. The idea of 2 stage furnaces is to have a long run cycle on a quiet, gentle low fire. Kinda like you do in your car. You don't have an on-off switch you toggle as you get cold and turn off when you get hot. You find a nice gentle warmth and are very comfy. You can do that with a 2 stage stat but not with a timer. The timer won't allow it. Period. I put my 2 stage in during a cold snap. Didn't have the 2 stage stat yet. That poor furnace couldn't decide what to do. With the "right" stat, it would have run & run on low. Inaudible and very comfortable. Instead it would come on low, run 10 minutes then switch to high. But that would immediately satisfy the stat and turn off. A few minutes later, it would repeat with constant cycles.

  8. #8
    Thanks for the Info, I think I'll get them to installed a 2 stage stat.

    With the 2 stage stat can you set the fan to be on at low speeds at all times?? With this 1 stage you per the manual you get the fan on at 56% of the high stage cooling. It seems to be blowing more air than my old furance with the fan setting on. If thats 56% of the max airflow I think my house will feel like a wind tunnel at 100%....

    Thanks for the help...

  9. #9
    did they leave the installation papers with you or just the owners manual?Check the manual for 2 stage operation with a single stage stat.

    I install heil furnaces and a two stage furnace will work with a single stg. stat by turning the #4 dip switch on the board to the off position.The system fires on high for about 1 min.then it switches to low fire for 12 mins.before changing back to high.

    Turn your heat on and stand by the unit to see if it switches.

  10. #10
    2 stage equipment deserves 2 stage controls!

    If not, why did they ever invent the two stage stat?

  11. #11
    Join Date
    Jan 2005
    Location
    Gilroy, Calif
    Posts
    188
    2 stage t-stat are nice and very expensive. You can see by some posts, that some recommend a 2 stage t-stat. Yours should run fine on a single stage t-stat. See your owners manual and makse sure it doesn't state you need a jumper (bridge) between W1 and W2 for it to go to high fire. The time between firing will determine the make of the furnace.

  12. #12
    Join Date
    Dec 2002
    Location
    Rochester, MN
    Posts
    5,304
    Go two stage stat.

    My parents built a new house last year, and they cheap out on a single stage t-state on the XV90 Trane.. It did ok with the timer. but it never ran long enought to make the basement comfortable..

    So I put in a Vision Pro two stage in for them this fall, and Mom said she already seen the comfort in the basement already.. She glad that I talked her into doing the two stage stat. Now she don't have to worry about dad freezing to death.

  13. #13
    Originally posted by gje1
    2 stage t-stat are nice and very expensive. You can see by some posts, that some recommend a 2 stage t-stat. Yours should run fine on a single stage t-stat.
    By your theory, he should have saved money and purchased a single stage unit.

    I will say that ALL of my new clients that have purchased a two-stage stat from my company (beings that they got a single stage stat with their equipment "installed by others") have been VERY happy with the improved results.

    Can't beat client feedback.

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