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  1. #1

    Angry Help - Bryant Hybrid Heat too hot on second floor

    I recently had a new Bryant Hybrid Heat system installed in my Connecticut home. The home is a two story colonial with 1600 sq. ft. The basement is not finished. The indoor equipment was installed in the attic and duct work run through closets to the first floor. The return is located in the second floor hallway, all registers are in the ceilings and the thermostats are located in the living room and upstairs hallway.

    The issue is that the second floor gets too hot. Overnight settings are 66F for first floor and 68F for second. When the furnace kicks on in the morning, the second floor temperature gets as high as 80F with all bedroom doors closed. The temperature will reduce to ~75F once the bedroom doors are opened. Second floor temperatures during the day average 72F and can be as high as 75F even with both thermostats set to 70F. Walking down the stairs you can feel the hot air is hugging the first floor ceiling and going straight up the stairs to the return.

    My questions are:
    1) Is this expected given the registers are in the ceiling?
    2) Is there anything that can be done to correct this? The only acceptable way for me to get ductwork to the basement for floor registers is to build a chase outside the house.
    3) Will the Evolution control work with using radiant floor heating as the auxiliary source instead of a furnace?

    My system includes the following Bryant components:
    - 3 ton, 3 stage furnace
    - 18 SEER heat pump and evaporator coil
    - Evolution zone control, damper control, smart sensor (upstairs)
    - Perfect Air Purifier
    -UV Light

    Thanks,
    Mark
    Last edited by flaubie; 01-14-2010 at 08:47 AM. Reason: Changed tittle

  2. #2
    Join Date
    Jul 2009
    Location
    Plant City, Florida
    Posts
    2,198
    Heat rises.

    Lower the temperature on the second floor.

  3. #3
    Join Date
    Jun 2007
    Location
    The Twilight Zone
    Posts
    2,964
    Wondering if the 3-stage furnace is not starting on 1st stage, or if the Evolution control is not set properly.

    Does this problem only occur when the furnace is running, or with the heat pump also?

    When you say that the 2nd floor temp gets to 80F, is that what the t-stat is showing or are you reading that temp somewhere else. What is the t-stat setpoint when it's 80F upstairs?

    You have a Merecedez-Benz caliber system. You should be satisfied with the way it works.

    Good luck.

  4. #4
    Join Date
    May 2008
    Location
    Missouri
    Posts
    3,504
    As previously posted, heat rises. Have you tried the system with the fan set at continuous? This should give you a more even heat. I assume your system is zoned, but you can still set the fan to run with dampers in open position between calls for heat/cool as an option if I remember right.

  5. #5
    Join Date
    Jul 2008
    Location
    Rochester NY
    Posts
    4,721
    Quote Originally Posted by wahoo View Post
    As previously posted, heat rises. Have you tried the system with the fan set at continuous? This should give you a more even heat. I assume your system is zoned, but you can still set the fan to run with dampers in open position between calls for heat/cool as an option if I remember right.
    No. Heat goes to cold. If the coldest object is the floor, you could say heat falls.

    Heated air in a leaky house will migrate up on it's way out. Cold replacement air comes in low in your envelope. Heated air is less dense than colder air and will create stack or chimney effect.

    There are 11ways from Sunday for controlling your infinity zoned system. Put one just like it in a 3500 sf house (5 zones). 60mbtu/3ton. We brought air leakage from 2800 to 2000. Homeowner ecstatic about comfort, control, and energy use. Something definitely amiss with yours.
    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.

  6. #6
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    67,913
    What kind of registers do you have. Are they round or square or rectangular.
    Do you have one return or 2, or more.
    Contractor locator map

    How-to-apply-for-Professional

    How many times must one fix something before it is fixed?

  7. #7
    Here are the answers to the reply questions.

    The set point on the 2nd floor is always 68F. I am reading the temperature off the t-stat in the hallway. It reads mostly 72F during the day and between 75F and 80F first thing in the morning with the the bedroom doors closed. I have been using my previous Honeywell t-stats to monitor temperature in two bedrooms and which gets to about 72F when the hallway is 80F.

    The system is zoned for the 1st and 2nd floors. There is only one return, it is in the 2nd floor hallway. There are rectangular, 1 and 3-way registers positioned in the ceilings at one end of each room.

    I have noticed the 80F temperature occurs when there is considerable hot air coming out of the 1sf floor ducts, no air out of the 2nd floor ducts. I believe the furnace is on high when this occurs. But I am still seeing 72F upstairs when the heat pump is on. I feel the system should be able to maintain temperatures closer than this to the set point.

    I believe the correct statement is heat flows from hot to cold, but hot air rises. All the hot air from the first floor ceiling registers is going straight up the stairs.

    The blower door test results were 1500 CFM at 50 psi. Since then I had the attic sealed with foam insulation to create a conditioned space (no registers or return).

    THANKS!
    Mark

  8. #8
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    67,913
    You probably have registers that are better for cooling then heating.

    A change of register, could make a big improvement. if they throw the air down. Instead of just along the ceiling and up the stairs.
    Contractor locator map

    How-to-apply-for-Professional

    How many times must one fix something before it is fixed?

  9. #9
    Join Date
    Jul 2008
    Location
    Rochester NY
    Posts
    4,721
    Tight house.

    In my neck of the woods you are looking at 40mbtu worst case heat load and 2 ton worst case cooling, unless you have crazy solar exposure.

    Ceiling registers downstairs, Hmmm. Large return upstairs? Blocked return downstairs? Too many variables to armchair diagnose.

    House that tight and small shouldn't need zoning. IMHO the time for zoning is really big house, or really bad house (construction or design). 1600cfm50 sounds like a really good house.

    Could be some dampers and connected to the wrong zones, could be return airflow issue, could be not enough supply in design (supposed to have 130% of lowest stage in smallest zone or something like that), could be they left some to dump to make minimum airflow, and that's causing wacky behaviors.

    You might try not being aggressive with setback or variations between zones. You might try continuous fan on both zones. Write down the parameters and results so you can look back over it.
    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.

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