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  1. #27
    Join Date
    Jul 2004
    Posts
    253
    Originally posted by docholiday
    Ok when you two girls are finished I would like to offer alternative questions.

    Is this a tweo stage system? If so, is there a way to override it to run at 100%.

    Im not busting chops here but if this is indeed a 2 stage, I recall looking a similar blue one up and it didnt have very good latent capacity on low stage, even when in dehumidification mode. If its a single stage then I am surely off base,

    Just food for thought but similar to the 180 mph speedo in my car, I can only do 120. Is it remotely possible the limited run time on this machine will not get the humidity any lower until the load increases? I mean just because the control has a set point that doesnt mean its got the capcity. Could it be oversized? If I remember correctly, this is a zoned system, are we dumping all the capcity into only one zone at a time?
    Hi Doc,

    Yes, this is a 2-stage Byrant system. Low-speed on the compressor is 50% - it is 1.5 tons at low-speed and 3 tons at hi-speed. The Evolution control regulates the fan coil speed and there is a humidistad. My HVAC guy caught the thing switching into heating mode periodically - apparently a known problem and he will be replacing the board in the condensor unit. Regardless, he thinks the condensate drip is way to slow and he claims that it should be able to get the RH into the 40% range. I havent seen the RH go below 57% whether in low-speed or high-speed. This is a new house with tight construction so I dont think air infiltration is an issue - it just doesnt seem to pull moisture out of the air.

  2. #28
    Join Date
    Apr 2004
    Posts
    7,680
    Yep, look at the product data sheets, the latent capacity for that unit on low speed is poor at best I think the equivelent Carrier one had on 995 btuhs of latent capacity on low stage (3 ton). (I dont mean to bring this up to make anyone mad, just thinking out loud). Again I may be off base but I dont think so.

    You probably posted it before but if you have model numbers of the outdoor unit, indoor unit, and indoor coil, I'm sure we can look it up. I may be thinkning of the 18 SEER one.

  3. #29
    FINALLY A NUMBER HAS "EVOLVED"

  4. #30
    Join Date
    Apr 2004
    Posts
    7,680
    Ok here goes, some of this is based on assumptions but hell, its a far cry better than you have gotten from anyone else.

    I believe you said it was 91 outdoors with a 63 dew point.
    I also recall you saying the return air was 75 degrees at 57% rh. (doing some calcs here)...

    I am assuming an fv4bn006 air handler...
    The outdoor WB is 71.77 and your humidity outside is (was) 39%. Your indoor wb is 64

    Now according to some interpolation of the product data...

    In low speed at 650 cfm (1.5 tons) in these conditions You have a total capacity of roughly 16,500 btuhs. The sensible capacity of that system is roughly 14,250 btuhs. This leaves you with a latent capacity of around 2,250 btuhs. If your airflow is higher, you can count on that being a lower value.

    I suspect your installer doesnt realize how little water you are going to wring out of the air with only 2250 btuhs of latent capacity. Theres a greater chance he never looked at the data the mfg supplies.

    heres the amazing thing....
    If your return wb goes down to 62 degrees...the system has 0 latent capacity. Ze-freakin-ro. How much mositure do you think its going to remove then? Reagrdless of what the control set point is. With a zoning system, this may very well be possible.

    Heres the link to the PDF... http://www.xpedio.carrier.com/idc/gr...s698b.24.4.pdf go to page 29. On the upper portion of the page you will see airflow to the left. you will see condenser entering air at the top and you will see return wb on the left. Line it up and look for yourslef.




  5. #31
    Join Date
    Apr 2004
    Posts
    7,680
    BTW, this is assuming the charge is correct which is still questionable if I remember correctly.

    And yes, it happens, they can overcharge it at the factory, its rare but it happens. Regardless the installer is responsible to make it right.

  6. #32
    Join Date
    Apr 2004
    Posts
    7,680
    There goes an hour of my life I'll never get back.

  7. #33
    Join Date
    Apr 2002
    Posts
    11,808
    Is this the system where the two stage compressor has to stop, allow for some pressure equalization, and then restart every time it switches speed?

    Could it be that it keeps drying its coil everytime it changes speed?
    The way we build has a greater impact on our comfort, energy consumption and IAQ than any HVAC system we install.

    http://www.ductstrap.com/

  8. #34
    Join Date
    Jul 2004
    Posts
    253
    Originally posted by docholiday
    Ok here goes, some of this is based on assumptions but hell, its a far cry better than you have gotten from anyone else.

    I believe you said it was 91 outdoors with a 63 dew point.
    I also recall you saying the return air was 75 degrees at 57% rh. (doing some calcs here)...

    I am assuming an fv4bn006 air handler...
    The outdoor WB is 71.77 and your humidity outside is (was) 39%. Your indoor wb is 64

    Now according to some interpolation of the product data...

    In low speed at 650 cfm (1.5 tons) in these conditions You have a total capacity of roughly 16,500 btuhs. The sensible capacity of that system is roughly 14,250 btuhs. This leaves you with a latent capacity of around 2,250 btuhs. If your airflow is higher, you can count on that being a lower value.

    I suspect your installer doesnt realize how little water you are going to wring out of the air with only 2250 btuhs of latent capacity. Theres a greater chance he never looked at the data the mfg supplies.

    heres the amazing thing....
    If your return wb goes down to 62 degrees...the system has 0 latent capacity. Ze-freakin-ro. How much mositure do you think its going to remove then? Reagrdless of what the control set point is. With a zoning system, this may very well be possible.

    Heres the link to the PDF... http://www.xpedio.carrier.com/idc/gr...s698b.24.4.pdf go to page 29. On the upper portion of the page you will see airflow to the left. you will see condenser entering air at the top and you will see return wb on the left. Line it up and look for yourslef.



    Hi Doc,

    The system has a 698B036 condensor and FE4005 fan coil with 4 zones.

  9. #35
    Join Date
    Jul 2004
    Posts
    253
    Originally posted by Carnak
    Is this the system where the two stage compressor has to stop, allow for some pressure equalization, and then restart every time it switches speed?

    Could it be that it keeps drying its coil everytime it changes speed?
    The system is in low-speed most of the time - probably over 80%.

  10. #36
    Join Date
    Aug 2002
    Location
    Office and warehouse in both Crystal River & New Port Richey ,FL
    Posts
    18,836
    There is something wrong with the install ,refrigeration system,or it's oversized.

    We have over 200 of the systems installed and we don't have humidity problems.

    Could be they overheated the TXV bulb on install.Could be undercharged,could be return duct leakage.

    Evolution has the ability to run at 270 cfm per ton,so 650 is not a given.I beleive the OP has seen around 500 cfm ,on low.


  11. #37
    Join Date
    Apr 2004
    Posts
    7,680
    I buy that, I can only use the numbers given and published.
    Certainly at 500 cfm it would have better latent capacity. That goes without saying. I too think its oversized but I have no data to prove it, just hearsay dignostics.

  12. #38
    Join Date
    Aug 2002
    Location
    Office and warehouse in both Crystal River & New Port Richey ,FL
    Posts
    18,836
    Originally posted by docholiday
    I buy that, I can only use the numbers given and published.
    Certainly at 500 cfm it would have better latent capacity. That goes without saying. I too think its oversized but I have no data to prove it, just hearsay dignostics.

    The irrating part is the don't publish the numbers for "all" cfms ,that it may operate at,at least that's what we are told.

  13. #39
    Join Date
    Jul 2004
    Posts
    253
    Originally posted by docholiday
    I buy that, I can only use the numbers given and published.
    Certainly at 500 cfm it would have better latent capacity. That goes without saying. I too think its oversized but I have no data to prove it, just hearsay dignostics.
    I doubt it is oversized. Two different load calculations came up with 3 tons for 3000 square feet.

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