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  1. #27
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    Aug 2012
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    Quote Originally Posted by jpsmith1cm View Post
    Only Professional Members have the option to use PMs on this forum.

    If another member has an e-mail address posted to their profile, you could use that to contact them.
    Sorry, I thought your PM message was meant for me.

  2. #28
    Join Date
    Aug 2012
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    I really appreciate all of your suggestions on how to fix the system. However, what I am looking for is documentation on what the static pressure should be. At some point the current dealer is going to declare the system is working a well as can be expected for my situation and request payment. I am going to have the system do a static pressure check at that point. Opinions here seem to vary but it sounds like the static pressure should be 0.8"WC or lower worst case. The problem is that is just an opinion of members of this forum and the dealer may disagree. Are there any Carrier documents, HVAC best practices, etc that state this in writing to back me up?

  3. #29
    Join Date
    Oct 2010
    Location
    Anderson, South Carolina, United States
    Posts
    7,093

  4. #30
    Join Date
    Oct 2010
    Location
    Anderson, South Carolina, United States
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    7,093
    The higher the static the more power you are using. It is kinda silly to put a high efficiency system and run it at 1" of static thus making it inneficient. I would like to see it around .5" if I were you

  5. #31
    Join Date
    Nov 2004
    Location
    SW FL
    Posts
    6,296
    I would set the MINIMUM "close" position on Zone 2 and 3 to deliver 50% AND ZONE 1 to deliver 60%.
    This minimum close position effectively gives you "dump" areas and minimizes (or eliminates) the by-pass and should keep the total air flow > 1,600 CFM.

    Supply header should be hard duct : ~ 30" x 10" by ~ 20 feet long to minimize the use of flexible duct and junction boxes.
    Designer Dan
    It's Not Rocket Science, But It is SCIENCE with "Some Art". ___ ___ K EEP I T S IMPLE & S INCERE

    Define the Building Envelope and Perform a Detailed Load Calc: It's ALL About Windows and Make-up Air Requirements. Know Your Equipment Capabilities

  6. #32
    Join Date
    Nov 2004
    Location
    SW FL
    Posts
    6,296

    Thumbs up

    BALANCING Example

    Given the nineteen diffusers,
    and the duct sizes for the Three Zones,

    Can the by-pass be minimized?
    Attached Images Attached Images
    Last edited by dan sw fl; 09-03-2012 at 08:23 AM.
    Designer Dan
    It's Not Rocket Science, But It is SCIENCE with "Some Art". ___ ___ K EEP I T S IMPLE & S INCERE

    Define the Building Envelope and Perform a Detailed Load Calc: It's ALL About Windows and Make-up Air Requirements. Know Your Equipment Capabilities

  7. #33
    Join Date
    Aug 2012
    Posts
    20
    Quote Originally Posted by jtrammel View Post
    The higher the static the more power you are using. It is kinda silly to put a high efficiency system and run it at 1" of static thus making it inneficient. I would like to see it around .5" if I were you
    I have read the Infinity Zoning Design Guide in your link. It has a lot of general guideance like making sure each zone can handle the minimum equipment airflow requirements, compatible equipment series, etc. It stresses the problems excessive static pressure can cause but it does not define what is considered acceptable static pressure. The closest I find is where it uses 0.6"WC from the product data sheet in an example duct friction rate calculation. The installation manual for my furnace lists an external static pressure range as 0-1.0"WC when paired with a 5 ton cooling unit. I'd like to see .5" also but I'm not sure it is an realistic expection for my situation.

  8. #34
    Join Date
    Oct 2010
    Location
    Anderson, South Carolina, United States
    Posts
    7,093
    If the duct is designed appropriately you should have no problem getting .5 - .6" ESP. That is the closest thing I could find on recommended ESP. Most install manuals will highlight the recommended static for the equipment in the table. Rule of thumb is .5"

  9. #35
    Join Date
    Aug 2012
    Posts
    20
    Quote Originally Posted by jtrammel View Post
    If the duct is designed appropriately you should have no problem getting .5 - .6" ESP. That is the closest thing I could find on recommended ESP. Most install manuals will highlight the recommended static for the equipment in the table. Rule of thumb is .5"
    Could you provide a reference for where that recommended ESP comes from? It could be usefull if the current dealer wants me to accept higher ESP.

  10. #36
    Join Date
    Jul 2008
    Location
    Rochester NY
    Posts
    4,735
    Quote Originally Posted by BigBacardi View Post
    i am fairly well versed in infinity zone systems.

    the installer should be shot.

    u cant have a 600 sqfoot room as on zone on a 5 ton 2 stage hp....cause first stage is almost 40kbtu!!!!

    of couorse your static is insane. you need a smaller hp or a larger area for the zones. the best be would be to try a new inverter hp. but alas u already paid for the existing one.
    you could try to change to only two zones....include the master with another zone.


    u my friend are in a world of hurt and no amount of jimi rigging is gonna help.
    So this thing pretty much heats and cools on low, and going to high triggers safeties. It heats on low all the way to 30, and 20 is design. Who did your heat load? Everybody seems cautiously implying the 800 lb gorilla... I'll step up and call this system grossly oversized not just to the duct, but to the house.

    How do you manage temperatures? That'll further express actual load. If you are asking for recovery from such a system, rethinking that may avoid headaches.

    What electric rates do you have? When you say "a lot of propane," what does that mean?

    My systems all report between .12 and .38 static - below .4 tends to be where you start seeing big energy use drops and reports of "I NEVER hear my system. Mfrs generally don't want higher than .5. Your ECM motor is Using a LOT of electricity and screaming "please, just shoot me" at the levels you report.

    Bigbacardi is probably right. Sounds like time to look at a 3 ton GREENSPEED with a 4 ton coil. Looking at Dan's nice work, 3 ton might be able to handle the small zone size.
    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.

  11. #37
    Join Date
    Oct 2010
    Location
    Anderson, South Carolina, United States
    Posts
    7,093
    Quote Originally Posted by Sterling9 View Post
    Could you provide a reference for where that recommended ESP comes from? It could be usefull if the current dealer wants me to accept higher ESP.
    Anything highlighted is above recommended static

  12. #38
    Join Date
    Aug 2012
    Posts
    20
    Quote Originally Posted by tedkidd View Post
    So this thing pretty much heats and cools on low, and going to high triggers safeties. It heats on low all the way to 30, and 20 is design. Who did your heat load? Everybody seems cautiously implying the 800 lb gorilla... I'll step up and call this system grossly oversized not just to the duct, but to the house.

    How do you manage temperatures? That'll further express actual load. If you are asking for recovery from such a system, rethinking that may avoid headaches.

    What electric rates do you have? When you say "a lot of propane," what does that mean?

    My systems all report between .12 and .38 static - below .4 tends to be where you start seeing big energy use drops and reports of "I NEVER hear my system. Mfrs generally don't want higher than .5. Your ECM motor is Using a LOT of electricity and screaming "please, just shoot me" at the levels you report.

    Bigbacardi is probably right. Sounds like time to look at a 3 ton GREENSPEED with a 4 ton coil. Looking at Dan's nice work, 3 ton might be able to handle the small zone size.
    I mostly have the problem when the temperatures are in the 50s and 60s. The heat pump will run on high stage below those temperatures. I live in California and new construction needs to comply with energy effeciency requirements (Title 24). The architect who designed the house used Micropass 7 software to do the heat load calculations and it takes all sorts of stuff into aaccount. I use a 3 degree setbback at night and set the zones to unocupied during the day when I am away. Initially I used a setback during the day but the Infinity manual says unoccupied gives the system more flexibility. I have a solar system so I never exceed the base electricity rates which is about $0.12 per kwh. Propane vaires around $2 a gallon. My first year here I didn't realize the system was switching to probane and used several hundred gallons in a few months (my water heater, dryer, and stove are also propane). I locked out the furnace down to 32 degrees after that and use a lot less propane. It is not practical for me to replace my system since I would wind up paying for everything at this point. Additionally. I really belive my problems would go away (or get a lot better) once the high static pressure is addressed.

  13. #39
    Join Date
    Aug 2012
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    I want to reiterate that what I need is documented literature stating what the allowable static pressure is for my system. I am just a homeowner that hired someone to fix a system that was installed incorrectly or is malfunctioning. One of the symptons is an excessive static pressure message. I could try pointing him to this thread if he tries to tell me anyghing below 1 is OK but I don't think it would get me very far. What would you do if you had a customer that refused to pay you because some people on a HVAC forum disagreed with your work? I'd imagine you'd want something more substantial than that. I'm getting the feeling that there isn't anything out there or it would have been offered up by now. It's just a little surprising to me that is so difficult to find the documentation.

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