suggestions needed for wifi zoned thermostats?

Discussion in 'General Discussions' started by jk96, Feb 17, 2016.

  1. jk96

    jk96 Member

    I'm hoping someone can give suggestions for wifi zoned thermostats with a central controller and phone app options as well. I ran across honeywell's evohome system which looks like what I'm after but I'm only seeing it in the UK for radiator systems. I've got two water to air units with 5 zones total.

    Some of the things I'm looking for
    - wifi with central controller and 5 zones
    - remote access via phone app
    - programmable

    Any suggestions?
     
  2. geoxne

    geoxne Active Member Forum Leader

    I suggest the Honeywell Redlink system. Although the components are not directly WiFi, an Internet gateway is available to control the system online through Honeywells Total Connect Comfort app and website. Redlink has been around for at least 5 years and has proven to be rock solid.

    This system can be as simple or as complicated as you want with many Redlink accessories available to control and/or expand your system.
     
  3. jk96

    jk96 Member

    Edit - actually 6 zones now that we have added the basement.

    Thanks geoxne. I'll look into it. Anything else others like? The main thing I'm after is a central interface to make it easy to adjust temps, turn off zones, etc without having to walk to each individual t-stat. A program only works part of the time since I often split time between home and office without any set schedule.
     
  4. urthbuoy

    urthbuoy Well-Known Member Industry Professional Forum Leader

    Redlink is the only wifi zoned air system I can think of. I installed some version of this about 7 years ago to save a very expensive house/system that had constant on radiant floors that warped the flooring. The original control wiring had been covered over with expensive hardwood walls and never connected. Somebody had messed up the order of contractors and at the time and their answer was to just leave it running.
     
  5. jk96

    jk96 Member

    Did some more checking today. It looks like the Redlink Gateway will only support 4 t-stats. If I'm reading correctly, it looks like I could install Honeywell Wifi T-stats and control all with the "total comfort" app. Would get pretty expensive with 6 t-stats though.
     
  6. geoxne

    geoxne Active Member Forum Leader

    One Honeywell Redlink Internet gateway will support 4 individual thermostats OR up 16 thermostats if they are connected to Redlink enabled zone panels.
     
  7. docjenser

    docjenser Well-Known Member Industry Professional Forum Leader

    How do you get enough air into the zone when only 1 of the 3 zones is calling and still keep the heat pump happy? I assume that you do not have a variable speed heat pump.
     
  8. jk96

    jk96 Member

    Hi Doc. Not quite following. Are you talking about how do I prevent sending too much airflow to a single zone? If so we have two 4 ton units. Each unit serves 3 zones. They have 2 stage scroll compressors so effectively run as a 2.5 ton unit with a lower airflow when in stage 1 with a single zone calling.

    Jeremy
     
  9. docjenser

    docjenser Well-Known Member Industry Professional Forum Leader

    Not too much, but enough airflow. Each heat pump serving 3 zones, by definition the smallest zone is max 33%, likely smaller. Now 1st stage is lets say 2/3 capacity, what happens when one 1 zone calls, the heat pump must get rid of 66% of its heat, but only has 33% (or less) ductwork to push the air through it. Unless you oversize your dicts, which then create a draft, noise and inefficiency in the zone.
    Not a good design idea, unless you have means to slow down the blower, and/or the compressor, further.
     
  10. jk96

    jk96 Member

    Hi Doc,

    The smallest zone we have would be our Master portion of the house. Looks like a 10" x 12" supply with 5 - 6"or 7" round trunks branching to registers. Not sure if this is enough to move the amount of air the unit needs to dump? Looks like stage one is around 1250 cfm's.

    Back to the main reason I posted. I picked up a honeywell RTH6500 wifi t-state for the basement zone yesterday to give it a try with the app. It seems to meet what I'm after however it will be going back due to no adjustment for temp swing differential. After 45 minutes on the phone with tech support I find it hard to believe that even their highest end model does not have a temp differential adjustment. They all call +- .5 degrees causing short cycles and more calls than I want. Looks like I'm going back to my "dumb" t-stat with an adjustable temp differential.

    Jeremy
     
  11. urthbuoy

    urthbuoy Well-Known Member Industry Professional Forum Leader

    The temperature differential setting is very unusual to have in an air system. I've never seen it or had a client request it. Most people want the temperature at the comfort level they set it at. To limit "short-cycling" I'd just limit compressor run times per hour.

    Radiant t-stats have it but it's for a different reason.
     
  12. jk96

    jk96 Member

    Chris my reason for wanting it goes back to my original post last year about excessive electrical usage. https://www.geoexchange.org/forum/threads/system-oversized-or-something-else.6310/
    In short an oversized system, very tight house, many zones, and small temp differential was causing cycles of 10-15 minutes of run time.

    Edit: Bumping up the temp differential doesn't effect our comfort level and resulted in much longer run times and less cycles.
     
    Last edited: Feb 18, 2016
    urthbuoy likes this.
  13. geoxne

    geoxne Active Member Forum Leader

    jk96 likes this.
  14. jk96

    jk96 Member

    Thanks Geoxne.

    Jeremy
     
  15. geoxne

    geoxne Active Member Forum Leader

    Keep in mind a zone panel can make a smart thermostat "dumb". Usually the zone panel is in charge of staging the system. Some zone panels stage based only on time elapsed. Some can also base staging on the % of zones calling and some can also pass tstat staging through to the equipment.

    What zone panel do you have?
     
  16. jk96

    jk96 Member

    My system staging is determined by the controller on the geo unit based on the pecentage of zone called. Each zone can be assigned a pecentage. If greater than 67% is called (all three zones in my setup) then the unit bumps to 2nd stage.
     
  17. jk96

    jk96 Member

    Hi Doc. Earlier in this thread you asked the above question. In reading through my system manual and features the below info caught my attention and may answer your above question.

    Standard Features for Modine Residential Models:
    EC Motor – Variable-speed ECM adjusts fan speeds to deliver constant airflow, regardless of external static pressure, resulting in consistent, gentle air circulation.
     
  18. docjenser

    docjenser Well-Known Member Industry Professional Forum Leader

    Means that the fan will speed up when only one zone is on to keep the airflow over the coil constant, the opposite of what you need. You need a controller which slows down the fan, and the compressor.
     
  19. jk96

    jk96 Member

    So based on my earlier post below do you think our smallest zone is too restrictive for 1200 cfms

    "The smallest zone we have would be our Master portion of the house. Looks like a 10" x 12" supply with 5 - 6"or 7" round trunks branching to registers. Not sure if this is enough to move the amount of air the unit needs to dump?"
     
  20. docjenser

    docjenser Well-Known Member Industry Professional Forum Leader

    20"x 12" in my book is good for 1200 cfm. You can be tricky and ensure that the the other zones do not close fully, so they bleed some cgms
     

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