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Thread: Bosch Bova Heat pump "Adaptive capacity output"

  1. #21
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    Quote Originally Posted by Cweldy View Post
    My Bosch unit can't maintain at anything above 85ish. Does not dehumidify well when it's not really hot outside. Barely able to get under 50% at 70 when it runs constantly. According to load calc it is slightly over sized. Roughly 30kbtu required at 100.
    If its holding a 37* coil, I dont see how its not pulling the moisture out. Is your fan set correct? is the airflow to fast across the coil to let the moisture condense?

  2. #22
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    Post all the operating performance numbers - unless the compressor isn't loading, the problem would seem to be in there.

    PHM
    ---------


    Quote Originally Posted by Cweldy View Post
    My Bosch unit can't maintain at anything above 85ish. Does not dehumidify well when it's not really hot outside. Barely able to get under 50% at 70 when it runs constantly. According to load calc it is slightly over sized. Roughly 30kbtu required at 100.
    PHM
    --------
    The conventional view serves to protect us from the painful job of thinking.

  3. #23
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    I think it's a board issue. When in charge mode it dropped roughly 1 degree every 15 minutes. Normal running conditions only about half the indoor coil sweats. In charge mode the whole thing sweats. I can't remember all the temps and pressures, but they were within factory spec. I believe I have one of the first off of the assembly line. Boards have since been updated.

  4. #24
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    There is a replacement board bulletin if they fall within a certain range. Not sure why you thinks its a board. Sounds like youre guessing without any info

  5. #25
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    I was told by one of Bosch's field reps to change the board since it was one of the first units, just because it's in celsius. All settings on unit are factory. A/h is a Bosch unit and blower speed settings are factory.

  6. #26
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    Quote Originally Posted by Cweldy View Post
    I was told by one of Bosch's field reps to change the board since it was one of the first units, just because it's in celsius. All settings on unit are factory. A/h is a Bosch unit and blower speed settings are factory.
    is the condenser also factory settings? if so then youre running a 47deg coil.
    Work sucks, lets go skydive

  7. #27
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    I have not changed anything on it. Accelerated cooling puts it at 37 correct?

  8. #28
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    Quote Originally Posted by Cweldy View Post
    I have not changed anything on it. Accelerated cooling puts it at 37 correct?
    correct
    Work sucks, lets go skydive

  9. #29
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    Also, I suspect the board because compressor was running at 40hz the other day. House was 2 degrees above set point and it was 95 outside.

  10. #30
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    you need to record your information. what if a pressure transducer is reading incorrect?, what if your airflow is incorrect? verify your airflow, Put it in charge mode, and after 20 mins record your superheat and subcool. wb etc... while you are in charge mode, scroll through what your bova thinks it sees on the temps and pressures. you may have other issues. However if your board is one they wanted to replace have at it. I would just go over all your data.

    You can also turn off the adaptive sw4-3 and see if that helps your troubleshooting
    Work sucks, lets go skydive

  11. #31
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    Quote Originally Posted by freefall View Post
    Im guessing you are oversized then
    IMO the term 'oversized' has a different definition when it comes to inverter drive AC...
    GA-HVAC-Tech

    Your comfort, Your way, Everyday!

    GA's basic rules of home heating and AC upgrades:
    *Installation is more important than the brand of equipment
    *The duct system keeps the house comfortable; the equipment only heats and cools (and dehumidifies)
    *Cheap is not good, good is not cheap; however expensive is not a guarantee of quality!
    Choose your contractor wisely!

  12. #32
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    I'm a homeowner, and a buddy (master electrician) put a mini split in. There is a tiny leak at the valve on the outside unit. He also bent my line set all to shit! I just ordered a new line set as well as some Nylog Red sealant. I also ordered a r410a manifold gauge set to test to see if it's holding a vac. So once I'm ready to replace the line, I will turn off the refrigerant valves so they are off, is there anything else I need to do ontop of turning the Freon off before replacing the lineset? Thanks guys and I would love all the help I can get!!!

  13. #33
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    Quote Originally Posted by Sohumn8 View Post
    I'm a homeowner, and a buddy (master electrician) put a mini split in. There is a tiny leak at the valve on the outside unit. He also bent my line set all to shit! I just ordered a new line set as well as some Nylog Red sealant. I also ordered a r410a manifold gauge set to test to see if it's holding a vac. So once I'm ready to replace the line, I will turn off the refrigerant valves so they are off, is there anything else I need to do ontop of turning the Freon off before replacing the lineset? Thanks guys and I would love all the help I can get!!!
    You need to start you own thread. Otherwise no one will see your post.
    Can someone please explain to me -
    Why is there never enough time to do it right the first time, but plenty of time to do it twice?


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  14. #34
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    its a 5 ton and the superheat and sub cool were in spec when installed in april. The condenser is only pulling about 8amps and the indoor coil is maintaining a delta of 21 to 23 degrees. at 8 amps i suspect it is only calling for about 2 to 2.5 tons of cooling so wouldn't 900 cfm be enough? My next step up on air flow is 1000/1550

  15. #35
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    5 ton is 2000 cfm.

  16. #36
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    Quote Originally Posted by freefall View Post
    5 ton is 2000 cfm.
    I understand if it was running at 5 ton capacity but its an inverter driven compressor and can go from 25% to 125% of its 5 ton rating. It uses suction temp to determine how much output the compressor is putting out.

  17. #37
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    Quote Originally Posted by ga-hvac-tech View Post
    IMO the term 'oversized' has a different definition when it comes to inverter drive AC...
    Oversized is easily defined, if you cant maintain < 50%RH on a design day in a green grass climate youre oversized. If you cant maintain 55% RH a humid climate your oversized. A 62 or 63 web bulb is the target.

    Ive looked at a few of these units and their latent performance is very underwhelming.
    Ed J

  18. #38
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    Quote Originally Posted by freefall View Post
    5 ton is 2000 cfm.
    only if the SHR of the home is between .8 and .85.

    I very rarely see the target in that range.

  19. #39
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    But how could that ever happen?

    As I understand the control logic; the evaporator is maintained at 37. The speed and pumping capacity of the compressor would vary to maintain that temperature.

    The cold coil would seem to be maximizing the moisture removal while lengthening the run cycles.

    How can these units avoid providing great moisture removal? What performance dynamic am I overlooking?

    PHM
    ---------



    Quote Originally Posted by Ed Janowiak View Post
    . . . I’ve looked at a few of these units (Bosch Bova) and their latent performance is very underwhelming.
    PHM
    --------
    The conventional view serves to protect us from the painful job of thinking.

  20. #40
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    Quote Originally Posted by Poodle Head Mikey View Post
    But how could that ever happen?

    As I understand the control logic; the evaporator is maintained at 37. The speed and pumping capacity of the compressor would vary to maintain that temperature.

    The cold coil would seem to be maximizing the moisture removal while lengthening the run cycles.

    How can these units avoid providing great moisture removal? What performance dynamic am I overlooking?

    PHM
    ---------
    Pretty simple, the unit(s) were touted as being able control humidity like no other unit could. Both houses I was in had RH> 60% with dry bulb temps in the mid to low 70s. < 400 CFM PT.

    I put a bucket under the white pipe and got less than 6 pounds of water after an hour of run time.

    I was expecting > 10.

    Non-invasive test.
    Ed J

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