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  1. #14
    Join Date
    Aug 2012
    Posts
    20
    OK, you asked for it, here is some more information about my house and system:
    I live in the foothills east of Sacramento, CA. My house is on a hillside facing west with a walk-out basement. The top level is 2120 sq ft. It has vaulted ceilings and a lot of windows. When I built the house I left the downstairs unfinished. The Title 24 for the top level lists a total heating load of 77,351 Btu/hr and a design cooling capacity of 53,507 for a conditioned area of 21,974 cf. The winter outside design temp. is 20 F and summer outside design temp is 97 F. That is what the system was initially designed for. I hired a contractor to provide and install the system (including all the ducting). I have since finished 363 sq ft of the downstairs and eventually will add another 367 sq ft. Two actively controlled zones are upstairs and the downstairs is one actively controlled zone. I normally leave the downstairs set to unoccupied and only condition it when I have a need, the upstairs zones are on a scheduled program. There is 1 20"x24" return (18" flex) and 2 14"x20" returns (10" flex) upstairs. the downstairs has a jumper duct to get around the door. The upstairs main living are (zone 1) is 1540 sq ft and has 2@5", 1@6", 6@8", and 1@10" supply registers. The master suite (zone 2) is 580 sq ft and has 1@6" and 3@8" registers. The downstairs (zone 3) has 2@6", 2@8", and 1@10" supply registers. The 10" register is temporary until I finish the downstairs.
    The new contractor took measurements with a magnahelic but didn't give me the results, I have asked him for them.
    I don't know it they ran the system with the blower door off. They did run the system with one of the large ducts off and the pressure was just below 1 (.93 I think).
    I will try to take pictures of the ducts this weekend if I get a chance.
    Thanks
    Sterling
    Last edited by Sterling9; 08-31-2012 at 10:06 PM. Reason: Fixed typo's

  2. #15
    Join Date
    Oct 2010
    Location
    Anderson, South Carolina, United States
    Posts
    5,674
    Is this problem happening when all zones are calling or only when 1 or 2 zones are calling. You may need a bypass damper to dump supply air into the return when all three zones arent calling to relieve the static build up caused by the restriction of closed zone dampers

  3. #16
    Join Date
    Aug 2012
    Posts
    20
    The main problem I have is when zone 1 is calling, that is the one that can't meet the heat demand on low stage and will start heating with the furnace. Zone 2 doesn't have a problem meeting the temperature rise rate on low stage. I had a different problem with zone 3. That zone would lock itself out. The new contractor added some more supply registers and the jumper duct. Hopefully that takes care of the problem but I won't know until winter.
    My understanding is you can't use bypass dampers with the Infinity system. However, the controller is supposed to dump into other zones when a zone is calling and the the airflow is inadequate.

  4. #17
    Join Date
    Oct 2010
    Location
    Anderson, South Carolina, United States
    Posts
    5,674
    Sorry I'm not too versed in infinity zoned units. Maybe it's not dumping the air off to other zones when airflow is increased

  5. #18
    Join Date
    Aug 2012
    Posts
    20
    I think the system is trying to dump into other zones. However, the static pressure of the whole system is too high so it doesn't help. I think that once the high static pressure issue is resolved the system will work properly.

  6. #19
    Join Date
    Oct 2010
    Location
    Anderson, South Carolina, United States
    Posts
    5,674
    If it is not dumping air to other zones when it should be that will make static pressure high. It's like taking a garden hose and crimping the end and pressure increases, when you uncrimp the end it flows at a lower pressure. In your system if all zones are open it's like the uncrimped hose when one zone closes its like partially crimping the hose then when 2 of three zones close it's like crimping the hose even more increasing static pressure enough to where it lowers to first stage which lowers the fan speed to get static pressure down to where it will operate by reducing flow, like turning the water faucet half open rather than fully open

  7. #20
    Join Date
    Dec 2011
    Location
    somewhere between here and there
    Posts
    478
    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.


    Please, Please Please......keep the Factory Smoke in the Wires!!!!!


    Is it Rum'Oclock yet???

  8. #21
    Join Date
    Sep 2008
    Location
    Western PA
    Posts
    24,998

  9. #22
    Join Date
    Aug 2012
    Posts
    20
    jpsmith1cm
    I can't figure out how to access my PMs (I don't have permission to access that page error). Can you send me an email?
    Thanks
    Sterling

  10. #23
    Join Date
    Sep 2008
    Location
    Western PA
    Posts
    24,998
    Quote Originally Posted by Sterling9 View Post
    jpsmith1cm
    I can't figure out how to access my PMs (I don't have permission to access that page error). Can you send me an email?
    Thanks
    Sterling

    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.

  11. #24
    Join Date
    Aug 2012
    Posts
    20
    I thought the Infinity system does the static pressure check with all zones open, am I mis-informed on that?

  12. #25
    Join Date
    Aug 2007
    Location
    Northern VA 38 degrees N by 76 degrees W
    Posts
    5,046
    Quote Originally Posted by Sterling9 View Post
    I thought the Infinity system does the static pressure check with all zones open, am I mis-informed on that?
    Your duct design is to restrictive for it to work, even if the zones excess bypass is fully open the zones are to small to except the cfm needed

  13. #26
    Join Date
    Aug 2012
    Posts
    20
    Quote Originally Posted by second opinion View Post
    Your duct design is to restrictive for it to work, even if the zones excess bypass is fully open the zones are to small to except the cfm needed
    That is what I suspect. I think the static pressure needs to be addressed first and then see if any problems remain.

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