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Thread: LR-TEMP-FLSH resistance?

  1. #1
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    LR-TEMP-FLSH resistance?

    I've looked every where and can not find a reference to what the thermistor resistance value is in the LR-TEMP-FLSH. Honeywell's are 20k and they have one that's 10k to hook in a series/parallel config with a another 20k sensor for averaging but they are not flush so what's Lutron's flush sensor. AprilAire and HAI Omnistat flush sensors are 10k and up until now I thought that was the norm.

    Now Honeywell does have a sensor affixed to a 1 gang metal plate C7772A1012 which they call a flush sensor which I supposed could be recessed on a box and taped over but IMHO this lack of a real flush sensor is pretty stupid. Not to mention nothing for remote humidity sensing. Wish Lutron partnered with AprilAire instead since most integrator are already familiar with working with them.

    Now since Honeywell uses a series parallel wiring scheme using two 20k and one 10k to achieve averaging might it be possible to use two 10k flush sensors in series be they Lutron's if that's what they are or AprilAire's of HAI's. There really should be more common sense being use with this stuff.

    Why no humidity sensors too, both wired and wireless.
    VAV
    Danbury, CT

  2. #2
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    You can see from this picture of Honeywell's averaging using two 20k thermistors sensors and one 10k thermistor sensor it's essentially two 10k thermistors in series since two 20k thermistors in parallel is effectively 10k so I would think two of AprilAire or HAI flush sensors would do just fine if wired in series. So what is the Lutron flush sensor 10k or 20k?

    Click image for larger version. 

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    VAV
    Danbury, CT

  3. #3
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    I went through this a couple of years ago. Lutron said the software doesn't support it. Honeywell said the hardware used by Lutron doesn't support it.
    LED, Incorporated
    Raleigh, NC 27614

  4. #4
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    Quote Originally Posted by randyc View Post
    I went through this a couple of years ago. Lutron said the software doesn't support it. Honeywell said the hardware used by Lutron doesn't support it.
    These are fixed resistance analog thermistors so if should be manageable applying additional resistance in series or in parallel or both. The diagram in my previous post shows that Honeywell supports this so it's a matter of knowing what the Lutron sensor is, I'd assume 10k either a second 10k thermistor or just a 10k resistor in series should work for Honeywell if you need a flush sensor.

    You would think Lutron would offer an approved tested fix for this stuff. Is Ziggy still around? Probably long since retired.

    What software? I could see if these were digital sensors like the ones used by Control By Web.
    VAV
    Danbury, CT

  5. #5
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    Here’s an example of what I’m talking about. Basic series and parallel resistence but with thermistors so we can use two 10k flush mount in series to use with Honeywell tstats. Now what are Lutron flush sensors? I know AprilAire and HAI flush sensors are 10k, sooooo what are lutrons?

    http://zenhvac.com/averaging-thermistors/
    VAV
    Danbury, CT

  6. #6
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    Come on! Some one from Lutron should know the resistence of the flush sensor. Do I have to call TS and waste their time?
    VAV
    Danbury, CT

  7. #7
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    I happened upon another post where Scottydont wrote:
    Aprilaire are the same ohms ...work great . Calibrated with my fluke IR gun.

    so these must be 10k thermostors. Would have been nice if someone from Lutron or from this forum could have responded with an answer. I wonder if the Vantage, C4 or Crestron folks have better support?
    VAV
    Danbury, CT

  8. #8
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    Hello vining,
    Thank you for your post.
    Sorry for the delay. Send an email to systemsupport@lutron.com and reference this post. I'll see what information I can get you and reply back to your email.

  9. #9
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    Thanks but I’m sure the lutron sensor is 10k. A bigger issue I see with the Lutron HVAaC controller or the Honeywell TouchPro is a lack of remote Humidity sensor which AprilAire and HAI does have. AprilAire has a support module which directly connects to their TSate for remore temp and humidity and HAI has a temp/humidity sensor which connects to their processor which also provides addition logic and a single point ability to change over from heat to cooling and vice/verse and since this house may have up to 40 tstats that would make changing seasons a lot easier. I could do the same with Lutron or AprilAire if I wanted to add and AMX processor but I still wouldn’t hace remote humidity with the Lutron options available.
    VAV
    Danbury, CT

  10. #10
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    Ok, we’re looking at Lutron again since the owner would like seeTemps in every room. Just an email with some questions.
    VAV
    Danbury, CT

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