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  1. #1
    Join Date
    Jan 2009
    Posts
    38

    Bryant Evolution Comfort Control (T-stat)

    I have a recent Bryant Evolution install. I like it so far. I have only had it on-line about four days. It is a hybrid system. My issue: I set it back to 60 degrees at night to come back up to 68 degrees at 6:00 am. Outside temps have been in the mid to low 30's. The problem: It is "late" in coming up to temp. It takes an additional hour or more for the house to get up to 68 degrees. In other words it is not 68* until 7:00am or later.

    Will the system "learn" what it has to do to meet the 7:00am time frame or does my tech need to come back and do some additional programing. It seems either it is not starting early enough or it is not in the correct stage to allow for the make-up in temp in the time frame. It does show that it is in the auxillary heat mode thus it is using NG as opposed to the heat pump. Thoughts?? Thanks. Mike L.

  2. #2
    Join Date
    May 2000
    Location
    Indianapolis, IN, USA
    Posts
    34,617
    If you want to raise 8 in cold weather, you'll have to use some gas. Most stats try to avoid using whatever backup knowing it costs more than the pump. Possibly the Evolution can be told you want a big setup even if it costs you more to recover and bring on more gas or gas sooner. Or better yet, use less of a setback to avoid using gas.

  3. #3
    Join Date
    Jan 2009
    Posts
    38

    Recovery time.......

    I just spent some time reading the install instructions as well as the owners operation booklet. The example Bryant uses is a 6* night set-back. They state that the Evolution Comfort Control (stat) will calculate the degrees per minute increase needed to arrive at the desired am temp using a 90 minute time period. It might be .04 of a degree per minute, as an example. The system has what's called Smart Recovery which allows 90 minutes to come up to temp. A six degree set-back will cause the aux. heat to be used. In my case NG. A 5* set-back or more may cause the aux heat to kick in. They caution against too great a set-back temp. causing the furnace to be unable to do the make-up in 90 minutes.

    I would like to do an 8* set-back but that may be too much. Is there a way to program the stat to ramp up the furnace to a higher stage during the "make-up time"? The other thing I could do is cheat the stat a little and ask for the increased temp to be met at 5:00 am instead of the desired time at 6:00 am. That would "give" it an extra hour to meet the demand.

    Other ideas? As always, thanks for the help. Mike L.

  4. #4
    Join Date
    Jul 2004
    Location
    Massachusetts
    Posts
    6,841
    There is no way to override the factory programming. However, unless you're down near design temperature for the gas furnace, it should easily be able to bring the home up to temperature in less than 2-hours, IMO. What concerns me is that having the gas furnace running is only part of the battle. The second half is making sure it's stepping up to high fire when the User Interface isn't coming up fast enough. I can tell you that the information in both the user's manual and the installation manual is a tiny fraction of what needs to be known to really work with Infinity (Carrier) or Evolution (Bryant) controls. There are specialists at the tech help center that deal with nothing but the finer points of those controls.

    Having said all of that, it's important to understand that the designers of the controls were charged with making the equipment as economical to operate as possible. Why else to have Hybrid Heat? What that means to you as the end user is that the chip in the User Interface makes decisions based on temperature trends as much as it does on actual temperature. As you already pointed out, they've programmed in an anticipated 90-minute step-up time with a maximum 5-degree spread. You're exceeding the design limit by asking for an 8-degree step-up. How the system responds to that request is a function of size, time and outdoor ambient conditions. It is entirely possible that at or near design temperature (OAT) you might have to wait all day to get the temperature up 8-degrees. Set back is digging a hole that the equipment needs to climb out of at the next programmed step-up cycle. It can only do that with Btu's in excess of what the home is losing per hour. At temps above design, there should be lots of Btu's available or "in the bank" so to speak. But at or close to design, there's not a whole lot of Btu's "in the bank" and so step-up can take a long, long time. If you want 8-degrees, methinks you'll have to either step-up earlier or put up with the delay. Just make sure the furnace is actually on high fire. If it's not, then that would make a huge difference as you're being robbed of the Btu's "in the bank" without high fire.
    If YOU want change, YOU have to first change.

    If you are waiting for the 'other guy' to change first, just remember, you're the 'other guy's' other guy. To continue to expect real change when you keep acting the same way as always, is folly. Won't happen. Real change will only happen when a majority of the people change the way they vote!

  5. #5
    Join Date
    Feb 2009
    Location
    pinehurst north carolina
    Posts
    58
    you should decrease the setback 8 degrees is plenty expecially when you consider that it will have to run for some time until it goes from 1st to 2nd to 3rd stage. Is the issue that you want to save money or is it that you like it really cold if its that you like it really cold then try 62 instead of 60 if its to save money. then you may want to raise the temp up to about 64 that way the only way the gas will come on is when it gets down below the heat pump lockout temp or if it goes into defrost.

  6. #6
    Join Date
    Feb 2009
    Location
    pinehurst north carolina
    Posts
    58
    Quote Originally Posted by skippedover View Post
    There is no way to override the factory programming. However, unless you're down near design temperature for the gas furnace, it should easily be able to bring the home up to temperature in less than 2-hours, IMO. What concerns me is that having the gas furnace running is only part of the battle. The second half is making sure it's stepping up to high fire when the User Interface isn't coming up fast enough. I can tell you that the information in both the user's manual and the installation manual is a tiny fraction of what needs to be known to really work with Infinity (Carrier) or Evolution (Bryant) controls. There are specialists at the tech help center that deal with nothing but the finer points of those controls.

    Having said all of that, it's important to understand that the designers of the controls were charged with making the equipment as economical to operate as possible. Why else to have Hybrid Heat? What that means to you as the end user is that the chip in the User Interface makes decisions based on temperature trends as much as it does on actual temperature. As you already pointed out, they've programmed in an anticipated 90-minute step-up time with a maximum 5-degree spread. You're exceeding the design limit by asking for an 8-degree step-up. How the system responds to that request is a function of size, time and outdoor ambient conditions. It is entirely possible that at or near design temperature (OAT) you might have to wait all day to get the temperature up 8-degrees. Set back is digging a hole that the equipment needs to climb out of at the next programmed step-up cycle. It can only do that with Btu's in excess of what the home is losing per hour. At temps above design, there should be lots of Btu's available or "in the bank" so to speak. But at or close to design, there's not a whole lot of Btu's "in the bank" and so step-up can take a long, long time. If you want 8-degrees, methinks you'll have to either step-up earlier or put up with the delay. Just make sure the furnace is actually on high fire. If it's not, then that would make a huge difference as you're being robbed of the Btu's "in the bank" without high fire.
    you can check to see if its in high heat by pressing the middle button on the right side of the control and it will show a snapshot of what is going on with the system

  7. #7
    Join Date
    Jan 2009
    Posts
    38

    Thanks to all.......

    Thanks for everyones thoughts, suggestions and input. I may well re-think my set-back temps. I was "used" to an 8* set-back but I had a system that was limited in what it could do and it certainly was not a hybrid. The Bryant system is really quiet. The heat pump function is so much better than the one I had twenty five years ago. There is no comparison. I am just "getting used" to this new Bryant. I want to use the functions as designed as well as be comfortable yet economical too. It is going to be a little trial and error at first I am sure. Thanks again. Mike L.

  8. #8
    Join Date
    Jul 2008
    Location
    Rochester NY
    Posts
    4,763
    You've gone from a system that likely had huge horsepower and short cycles. Big setbacks might actually have improved the efficiency of such a unit, it would get to operational temps at least the one cycle per day.

    Now you have a system that gets it's greatest efficiency on a flat highway - cruise control. Throw a mountain in there and I think you actually loose some of the heat pump's advantages.

    If 8 degrees is not for comfort, make the setback smaller.
    Which makes more sense to you?
    CONSERVATION - turning your thermostat back and being uncomfortable. Maybe saving 5-10%
    ENERGY EFFICIENCY - leaving your thermostat where everyone is comfortable. Saving 30-70%

    DO THE NUMBERS! Step on a HOMESCALE.
    What is comfort? Well, it AIN'T just TEMPERATURE!

    Energy Obese? An audit is the next step - go to BPI.org, or RESNET, and find an auditor near you.

  9. #9
    Join Date
    Dec 2007
    Location
    Cedar Grove, Wi-Sheboygan
    Posts
    1,582
    I don't havew the Hybrid heating but have half of the system (Infinity 58MVC) and use a 4* setback starting at 10pm. and to raise it by 5am. to 68* and works great, best thing for you to do IMO would be to adjust your setback to 5* or 6* and set it and forget it and let the controller do it's job, after a couple of weeks you can then tweak the controller to adjust some of the finer settings of the controller once you decide what needs to be adjusted. In a couple of weeks the controller will develop a history of how to heat your home based on your home and outside temps and will use the best method to heat your home but that can't happen if your continually changing settings on the controller everyother day or have too much of a set back for the HP and or Furnace to handle to give you the most economical heating. SO in the end 1 or 2 degrees one way or another isn't going to make that much of a difference on your monthly utility bill, but by not making the furnace or HP work harder than it needs to will save you more in the long run than the couple of bucks your tryint to save monthly will.

  10. #10
    Join Date
    Jan 2009
    Posts
    38

    Again...thanks for the thoughts.........

    Again, thanks to those who have shared thoughts. I agree about not changing settings too quickly. In fact, I am still hanging with the original settings. I have not changed anything as of yet because I wanted to get some sense of how the system was going to perform with the original settimgs. I want to establish a bench mark. They were set on Feb. 11 in the am. The original/current settings are:

    60* 10pm / 68* 6am / 60* 8am / 68* 3pm

    It now seems I may be better off with a swing temp of no more than 4*. I am thinking of: 62* 10pm / 66* 6am / 64* 8am / 68* 3pm

    Is it true that more than a four degree increase causes the aux heat to ALWAYS come on? NG in my case. Or will the controller learn/use the BEST way to bring on/up the temp. Would it NEVER be in the interest of economy to set back more than 4* ?

    Lastly, can it take several weeks for the controller to learn what it needs to do? I thought it would learn faster.

    Again, thanks.

    Mike L.

  11. #11
    Join Date
    Jul 2008
    Location
    Rochester NY
    Posts
    4,763
    The only "always" in this stuff is "it depends".

    Fast recovery is like getting a V8 instead of a 4 cylinder engine. Multi stage helps as it's like having a v8, a V6, and a 4 cylinder.

    The system you have can give you fast recovery, but using the V8 won't save you money. Might as well put in the 4 cylinder, get to the highway and set the cruise control - particularly with a heat pump.

    Anybody have a better analogy?
    Which makes more sense to you?
    CONSERVATION - turning your thermostat back and being uncomfortable. Maybe saving 5-10%
    ENERGY EFFICIENCY - leaving your thermostat where everyone is comfortable. Saving 30-70%

    DO THE NUMBERS! Step on a HOMESCALE.
    What is comfort? Well, it AIN'T just TEMPERATURE!

    Energy Obese? An audit is the next step - go to BPI.org, or RESNET, and find an auditor near you.

  12. #12
    Join Date
    Dec 2008
    Posts
    90

    I'm humping yet another thread....

    I've got the Carrier 58MVC and Infinity Control.

    The weather's been really mild (high 30's to low 70's) since moving into this house (tight envelope), and we're still using the factory presets on the Control (I believe it's the same as the above poster's).

    I have ONLY ever seen the burner running at MED (when it IS running) -- never at low.

    Even if we override the preset temp, and try to raise it 2* ... it operates at MED -- not LOW.

    I have no idea what will happen when Northern Colorado decides to unleash its Arctic fury (whether or not HIGH will come on), but ... does this sound right to you good folks??

    The calcs showed it was a virtual coin toss between the 60k and the 80k BTU.

    Figuring (I know, I know! ) that a multi-stage furnace with an ECM blower would be smart enough to do just what it needed to do, and no more ... I took the 80k. If ANYTHING, "logic" (see above) would lead me to think it would spend MORE time at LOW than the 60k, but ...

    Thoughts?? The installer comes out in a few days ... for an inoperative and incorrectly hooked-up Honeywell TrueSTEAM. Does it sound like there's yet another thing to be fixed ...

    Many thanks!

  13. #13
    Join Date
    Dec 2008
    Posts
    90

    Okay ... I'm dangerous ;-)

    I went into the basement, and found the install/instruction manuals () ... and here's what I did:

    Changed the configuration of the furnace:

    - STAGING - from MEDIUM to SYSTEM (default), and

    - AIRFLOW - from COMFORT to EFFICIENCY (default)

    Now, when I ask for 2* more, the furnace comes on at LOW

    I presume this will increase run time OF the furnace/fan, and will also help with ongoing HEPA filtration and (when the darned thing is fixed ) humidification.

    Seems I just let the animal be what it was born to be: fully automatic and modulating.

    Anybody see any issue with the changes I made??

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