New York Zoning

Discussion in 'General Discussions' started by Stickman, Apr 7, 2015.

  1. Stickman

    Stickman Member Forum Leader

    Mark, from the other live thread: "Zoning a system is a snap with the ECM drive blowers." Didn't want to hijack that thread, so I started this one.

    I've been wanting to find out what's involved, and what the potential outcome is, of zoning. I've got a split level house, with all four levels as living space. No cathedral ceilings, loft spaces, just closed stairways between all floors. Also have a split (no pun intended) CM 4 ton system, air handler in the unfinished attic. Upper 2 floors are warmer than lower 2 year round. When system is moving air, things are more even/comfortable. I've been running the fan constantly and that does help, to a degree. But when the compressor goes off in the dead of winter, the lower floors (where we watch TV, etc...) cool down very rapidly.

    I've looked at the Arzel equipment you've been recommending, and understand the overall concept. I have the manual J, and the calculated load looks consistent with my usage history. However, according to that report, the number and sizes of ducts specified is not what I got. For example, if a bedroom was spec'ed for two 4 inch supply ducts, I got one 6 inch instead (measurements for example purposes only). I have just one central return located in the hallway ceiling on top floor.

    How can I be as sure as possible that I'll get good results? What I'm struggling with is determining if my ductwork is "good enough" before incorporating zoning. And the answer to this seems obvious, but I'll ask anyway - can I expect my power usage to increase with the second zone added?

    Last edited: Apr 7, 2015
  2. urthbuoy

    urthbuoy Well-Known Member Industry Professional Forum Leader

    Not too hard at all. We're retrofitting a 2-zone system this week, so things are fresh in my mind.

    The number one important thing, in my mind, is the return air (or supply to the equipment). You have to make sure, no matter how small the zoning goes down to, that you have adequate air volume to the equipment. Of course your curtains may blow to the ceiling, but that is secondary:).

    So figure out what airflows the equipment can work with (min's) and figure out what type of ducting you have for both supply and return. Ducting has a recommended air flow based on its size that you can google a chart for.

    Now you don't magically fix bad ducting with zones. If that far bedroom gets no air and too much goes to the main kitchen, you may still have the same issue with zoning.

    The other thing to keep in mind is you need a zone board to make smart decisions based on the calls from multiple thermostats.

    edit - Yes, I think you could expect your power usage to increase with zoning. As now you are conditioning a space to a desired temperature that was never adequately conditioned before. In theory anyway. And assuming it wasn't "over" conditioned.
  3. Stickman

    Stickman Member Forum Leader

    For starters, all my registers are ceiling mounted, so the curtains are safe:D.

    Point taken about return air. With just the one central hall return on the top floor, this may require modification. Assuming I can measure the output of all the ducts in the proposed zone for the lower floors, and that amount of airflow is above the air handler's minimum requirement, how can I tell if the existing return is adequate?

    With regard to necessary equipment, I think I should go with individual duct dampers (because all runs branch off from the supply plenum on the AH), a zone controller, and proper thermostats. Is there anything else I'm missing?

    I'm trying to address this before the next heating season, and am willing to give it a try on my own. If my return, or supply for that matter, turn out to be insufficient, I would call in a pro. But if zoning on its own gets it done, I wouldn't mind the savings. I guess I'm looking for a primer on this. Thanks!
    Last edited: Apr 11, 2015
  4. NathanB

    NathanB New Member

    How did you make out with zoning? I have considered this as well - having a two storey home. Have two main returns, one on each level. Was more thinking of putting zone dampers on these returns vs supplies. Thinking let's cool the warm air and heat up the cool.
  5. Stickman

    Stickman Member Forum Leader

    No renovation as of yet. Got into a separate conversation that had me gathering all supply duct sizes to determine the new supply plenum configuration. Intent was to install two dampers in the plenum, one for each zone. I have an ECM blower, and it was mentioned that this greatly simplifies things. My goal is to get this done before the next heating season, and I may have to call in a pro if time grows short. Will post updates as they happen.
  6. docjenser

    docjenser Well-Known Member Industry Professional Forum Leader

    Zone dampers should be on the supply. If they are on the return, you still distribute the air to all zones, not very effective.

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