WaterFurnace/Intellizone Thermostat troubles

Discussion in 'Maintenance and Troubleshooting' started by Di2009, Jan 15, 2009.

  1. Di2009

    Di2009 Member

    Soil condition vs depth

    Closed loop, 5 ton Envision, 3000 ft horizontal loop - buried 4ft deep in heavy clay with very high water tables. Current loop temp read today was 28.6 In and 26.3 out. Temp outside is -20C

    How much effect if any does clay have on the operational effect of the loop, or is it just the over depth that matter?
  2. Palace GeoThermal

    Palace GeoThermal Well-Known Member Industry Professional Forum Leader

    The soil type and the moisture content both affect the conductivity.

    The attached chart lists the types from highest to lowest.
  3. engineer

    engineer Well-Known Member Industry Professional Forum Leader

    side note

    Given a delta-T of only 2.3 deg F across unit, system may be substantially overpumped - flow too high. This costs efficiency owing to excessive pump power.

    It is possible that high flow is needed to maintain turbulence in loop, but I would hope the loop was designed to not need that.

    -20 C implies pretty cold climate, so loop temps, while low, may not be too bad. That and given the weather, the unit has probably been running at greater than design load for days.
  4. Di2009

    Di2009 Member

    Last night before installer left after flushing system, the thermostat gave a "sensor error" but he repower'ed it and that went away.

    However, the system ran all night and I awoke to a very confused theromostat! I have a Waterfurnace 96P684-01 with factory default settings except set to non-programable.

    The temp on the thermostat is fluctuating between 17C to 20C within a few minutes of itself back and forth (have it set to achieve 22C).

    It says it's running Aux 2 all the time with fan, but the installer disabled the Aux dip switch and the air out the vents is very cool.

    The thermostat manual has tons different options of settings - i really just want a basic constant temp 24hrs a day - should any of the factory defaults be changed to obtain that?
  5. Di2009

    Di2009 Member

    Thanks - so how would the depth effect all of this? ie. if soil was the most favourable, would it matter if it was 4 feet or 6 feet?
  6. Palace GeoThermal

    Palace GeoThermal Well-Known Member Industry Professional Forum Leader

    On a 8 ton system in Montana,

    a 4' deep loop would need 1660' of trench to provide min EWT of 30°

    a 6' deep loop would need 1105' of trench to provide min EWT of 30°

    a 6' deep loop with 1660' of trench would provide min EWT of 34°
  7. Boiler74

    Boiler74 New Member

    Hello All. I'm having troubles with my Waterfunace system. Basically, the thermostats keep calling even after they have reached temperature. On two occassions in the past couple of weeks the system kept running after reaching, and then going over, the set temperature. Thermostat set on 70, and reading 72. And then today I noticed the system was running a lot, so I paid attention. The thermostats would be at temperature (set on 70 and reading 70) but would be calling for heat. And the system just kept running in Y1. Something just isn't right with this system. Are my thermostats shot, new board, what.

    My system stats: E series (Model E060TR111NBDSSA)installed in '06

    Intellizone system with two zones. Has had a new IRC chip with software upgrade to allow for 4 staging options.

    I would really appreciate your input on this. I know these units are not meant to run like this all the time.


  8. teetech

    teetech Member Forum Leader

    What thermostats are you using?
    Did the problem start with the new chip?
    Intellizone with new chip is still 3 stages.
  9. Boiler74

    Boiler74 New Member

    The thermostat is a Honeywell T8611M2033. And no this didn't start with the new chip. Have had it for a year or two. The chip description says it allows for normal, faster, quicker, and quicker with timer. Maybe that isn't 4 stage?

    Any help still greatly appreciated.
  10. teetech

    teetech Member Forum Leader

    That is referring to how aggressively the board will upstage, not the amount of stages.
    A thermostat will read in tenths of a degree internally so it is possible to set @ 70F and sill run Y1 at set temperature. It should not however go above set temperature. The Intellizone has many LED lights to help diagnose problems so you can look at the inputs from the thermostats to see if they are still calling above set point.
    Another possibility would be a damper not closing when thermostat quits calling. You would know this by checking for air movement from registers when thermostat is not calling.
  11. Boiler74

    Boiler74 New Member

    I do have the cover off the Intellizone panel and the thermostat is definately calling in Y1. And the dampers are operating. My biggest concern is this would be from the thermostat continuing to call after it has reached the set point. Like when it was set on 70, and still running and calling when reading 72. That isn't right. So do I need a new thermostat, or is this indicative of something larger? I tried today to find a replacement thermostat, thinking I could just swap it out. But apparently I can't, not even from a local HVAC wholesale supply store I have access to.

  12. geome

    geome Member Forum Leader

    Our non-zone Honeywell thermostat has settings for "Less Aggressive", "Standard", and "More Aggressive". Honeywell states that if you get temperature overshoot with Standard, to try Less Aggressive.

    I have observed, but not documented, that the Less Aggressive setting keeps the system running in lower stages longer. Hope some of this helps.
  13. Boiler74

    Boiler74 New Member

    Ok, so when I got home today, the thermostat was set on 70 and reading current temperature as 70. But the dang thing was calling for Y1, Y2, and Y3 (aux heat)!! In fact, I just now went and checked it and it is still doing it. What the heck?!?!?

    The system is set to the less agressive setting already.

    edit: Also wanted to say it's only 30 degrees outside. Not -10 or anything
  14. teetech

    teetech Member Forum Leader

    Any 3 heat 2 cool heat pump thermostat will work with the Intellizone. If an HVAC supply house can't come up with that go to a big box store. I know Lowes has them.
    I can't imagine an HVAC supply house not having a 3/2 stage HP thermostat.
  15. geome

    geome Member Forum Leader

    I have not ordered from these folks, but their pricing seemed good on what I wanted last year. Our installer ended up getting close enough to their pricing, so I went with the installer.
  16. geome

    geome Member Forum Leader

    Two other thoughts. May not work, but can easily tried and changed back if not helping.

    Set CPH for Aux heat to 1. Should at least keep the aux from turning on more than 1 time per hour.

    On the thermostat, have you tried using the indoor temperature offset? Maybe setting the offset 2-5 degrees warmer would help.

    Again, I'm not a pro, and don't know much about zoned systems.
  17. Boiler74

    Boiler74 New Member

    Tech came out today, and the water furnace is operating as it should. The thermostat in question is being replaced under warranty, and they are replacing the other one as well. Hopefully this fixes the problem. Thanks all for the replies, and I will let you know if the stats work.


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