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  1. #40
    Join Date
    Aug 2002
    Location
    Office and warehouse in both Crystal River & New Port Richey ,FL
    Posts
    18,836
    Still waiting for coil temp difference numbers, during the heat of the day.

    The hood used for cfms matched closely to the supply cfm ,but not the return,idicating return leakage.Though they think the hood is not working,but it was fine for supply??

    All tuccillo needs ,is to have them test the return air temp., at the inlet of the air handler ,versus indoor air temp.,to confirm or possibly eliminate return duct leakage.

  2. #41
    Join Date
    Sep 2004
    Posts
    3,157
    Lets go back to the charge a minute. 71 ft lineset? did they put the condenser across the street? I am just guessing here but I doubt they overcharged it enough to cover a line set that long. Doesnt he say that no additional 410a was added?

  3. #42
    Join Date
    Jul 2004
    Posts
    253
    Originally posted by ct2
    Lets go back to the charge a minute. 71 ft lineset? did they put the condenser across the street? I am just guessing here but I doubt they overcharged it enough to cover a line set that long. Doesnt he say that no additional 410a was added?
    Yes, the line set is 71 feet and no additional R410a was added ( which means that the condensor was over charged by 30 ounces or it is low on R410a )

  4. #43
    Join Date
    Jul 2004
    Posts
    253
    Originally posted by dash
    Still waiting for coil temp difference numbers, during the heat of the day.

    The hood used for cfms matched closely to the supply cfm ,but not the return,idicating return leakage.Though they think the hood is not working,but it was fine for supply??

    All tuccillo needs ,is to have them test the return air temp., at the inlet of the air handler ,versus indoor air temp.,to confirm or possibly eliminate return duct leakage.
    Hi Dash,

    The return temperature at the fan coil today was 70 - the return grills were about the same. On the other side of the coil it was 49.

  5. #44
    Join Date
    Aug 2002
    Location
    Office and warehouse in both Crystal River & New Port Richey ,FL
    Posts
    18,836
    So that's 5° better than previously posted ,what was it at the supply grilles,close to 49°??

  6. #45
    Join Date
    Jul 2004
    Posts
    253
    Originally posted by dash
    So that's 5° better than previously posted ,what was it at the supply grilles,close to 49°??
    Hi Dash,

    I dont know - they didnt measure at the supply grills ( or didnt mention the reading at the supply grills ) - they adjusted the R410A level - took out 9 ounces.

    Measurements of the airflow through the supply and return grills still shows the returns about 150 CFM less than the supplies. The ducts seem very tight so I question the accuracy of the flow hoods - he is coming back with a different flow hood to recheck. They have been concentrating on verifying the refridgerent level and the tightness of the duct work.

    One question I have for you based on a previous post by someone else is the ability of the 2-speed Evolution system to control humidity at low-speed. The specs seem to indicate that the latent capacity of the system at low-speed is very small. Have you found that you can get good humidity control at low-speed? My system is a 3-ton. Thanks Dash - I appreciate your help.

  7. #46
    Join Date
    Aug 2002
    Location
    Office and warehouse in both Crystal River & New Port Richey ,FL
    Posts
    18,836
    Originally posted by dash
    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.



    As noted the specs don't reflect the cfm that it can operate at.

    We have not had problems ,though our customers may not be watching it as closely as you are.However I and others at work have the two speed ,and no problems.


    We find that even in mild rainy weather,<54% RH is maintained.


    I thought you had stated that return to supply grille is/was 16° difference,if so now it is 21°,at the coil,then you need to know why the 5° difference.


    Also when looking at the low speed latent,look at the extended run hours it has due to 50% of total high speed capacity.Longer run times,at lower latent ,can be better then higher latent and shorter run times.

    [Edited by dash on 05-27-2005 at 11:21 AM]

  8. #47
    Join Date
    Mar 2004
    Posts
    1,042
    Originally posted by tuccillo
    ...
    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.
    When you say it has a humidistat, are you talking about the humidity control built into the Evolution control, or a separate humidistat with a knob on it somewhere?

    If an Evolution or Infinity system gets installed with a separate humidistat, it's a sure sign the installer didn't know what they were doing.

    There may be one or more incorrect settings in the installer setup of the Evolution control. Is the system overcooling at all in trying to get to the humidity setpoint? In some cases they will go as far as three degrees below the cooling setpoint to try to get the humidity level down low enough. BUT- if you're at 57% and the setpoint is 54%, it's not going to try that hard to get to 54%. You won't see three degrees of overcooling until there's a bigger differential between the RH setpoint and actual.

    What RH setpoint are you using? You mentioned 54% earlier. If that's what you're really using, I'd advise cranking that way down. I keep my Infinity system set for 48%, and it does a great job of maintaining that even though I have a single speed compressor.

    A 16-18 degree split is fine on this system if there's not demand for serious dehumidification. If it's really trying to prioritize dehumidification over cooling, you will see much, much larger splits though. That's what gets it to really wring a lot of water out. I think they will go down to as low as 275 cfm/ton with furnace-based systems and 250 cfm/ton with air handlers when they're really trying hard to dry things out.

    Offhand, I'd say to make sure it's set for
    ...on the installer pages:
    AC Airflow = Comfort (or at maybe Efficiency, but not Maximum)
    Dehum Airflow = Normal
    High Cool Latch = None
    Cycles per Hour = 4

    ...on the homeowner's Advanced Setup, screen 4:
    set a low humidity setpoint (heck, turn it all the way down for now)
    Dehumidify = On

    At that point I think you will have a humidity setpoint of 46%. If you started with a 54% setpoint like I think you may have, it's going to start putting out just a wee bit of icy cold air as soon as it registers the change and starts really tring to dry things out. You should see 25+ degree splits when it's working hard to dehumidify and it's not several degrees behind the temperature setpoint.

    From the main screen, you can hold down the right side button for about three seconds to see the current system status, including current RH versus the RH setpoint.

  9. #48
    Join Date
    Jul 2004
    Posts
    253
    Originally posted by wyounger
    Originally posted by tuccillo
    ...
    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.
    When you say it has a humidistat, are you talking about the humidity control built into the Evolution control, or a separate humidistat with a knob on it somewhere?

    If an Evolution or Infinity system gets installed with a separate humidistat, it's a sure sign the installer didn't know what they were doing.

    There may be one or more incorrect settings in the installer setup of the Evolution control. Is the system overcooling at all in trying to get to the humidity setpoint? In some cases they will go as far as three degrees below the cooling setpoint to try to get the humidity level down low enough. BUT- if you're at 57% and the setpoint is 54%, it's not going to try that hard to get to 54%. You won't see three degrees of overcooling until there's a bigger differential between the RH setpoint and actual.

    What RH setpoint are you using? You mentioned 54% earlier. If that's what you're really using, I'd advise cranking that way down. I keep my Infinity system set for 48%, and it does a great job of maintaining that even though I have a single speed compressor.

    A 16-18 degree split is fine on this system if there's not demand for serious dehumidification. If it's really trying to prioritize dehumidification over cooling, you will see much, much larger splits though. That's what gets it to really wring a lot of water out. I think they will go down to as low as 275 cfm/ton with furnace-based systems and 250 cfm/ton with air handlers when they're really trying hard to dry things out.

    Offhand, I'd say to make sure it's set for
    ...on the installer pages:
    AC Airflow = Comfort (or at maybe Efficiency, but not Maximum)
    Dehum Airflow = Normal
    High Cool Latch = None
    Cycles per Hour = 4

    ...on the homeowner's Advanced Setup, screen 4:
    set a low humidity setpoint (heck, turn it all the way down for now)
    Dehumidify = On

    At that point I think you will have a humidity setpoint of 46%. If you started with a 54% setpoint like I think you may have, it's going to start putting out just a wee bit of icy cold air as soon as it registers the change and starts really tring to dry things out. You should see 25+ degree splits when it's working hard to dehumidify and it's not several degrees behind the temperature setpoint.

    From the main screen, you can hold down the right side button for about three seconds to see the current system status, including current RH versus the RH setpoint.
    It only has the Evolution control. It has not been able to get below about 57% humidity running at low-speed. It does cool approximaely 3 degrees below set point but doesnt get the humidity nay lower. The installer adjusted the R410a level yesterday and had it running at high-speed for several hours - it did drop the humidity to 51% running in high-speed for several hours. Today is a nice day so the windows are open - I will try again once it get warm to see if the RH control is any better. The installer agrees that it should pull the RH into the 40s.

  10. #49
    Join Date
    Dec 2003
    Posts
    2,392
    The only relative humidity reading I would trust is one taken with a sling psychrometer. You could be getting all worked up over a number that is incorrect to begin with.

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