Results 1 to 5 of 5
  1. #1
    Join Date
    Feb 2012
    Posts
    42

    EXV forced closure?

    I recently noticed that my air handler / indoor coil has a pair
    of dry-contact input terminals to force its EXV to CLOSED during
    cooling mode.

    When/why would you want to do this, and/or why would such a
    function want to be able to be externally automated? I can't
    imagine how it could be good for the rest of the system.

    tnx

    _H*

  2. #2
    Join Date
    Aug 2003
    Location
    Fort Worth, TX
    Posts
    11,086
    What indicates that this is what the set of dry contacts are for? Dry contacts are often for alarm triggering purposes.
    • Electricity makes refrigeration happen.
    • Refrigeration makes the HVAC psychrometric process happen.
    • HVAC pyschrometrics is what makes indoor human comfort happen...IF the ducts AND the building envelope cooperate.


    A building is NOT beautiful unless it is also comfortable.

  3. #3
    Join Date
    Mar 2009
    Location
    Mid-Mo
    Posts
    3,428
    Hobbit it this on your Daikin system we have talked about before?

  4. #4
    Join Date
    Feb 2012
    Posts
    42
    Yup, the Daikin FTQ type air handler. Quoting from the
    install manual description for option block terminals 9,10:
    "Receives input: Forced closure of indoor unit Electronic
    Expansion Valve during cooling operation. (dry contact)"

    Seems like a strange thing to want an input for. Note: this
    isn't the same as "forced off" that you'd use for safety
    switches, condensate-pump overflows, etc.

    _H*

  5. #5
    Join Date
    Sep 2012
    Location
    Central Florida
    Posts
    880
    Sorries did not notice this was in the ask a pro section.
    Last edited by Elfshadow; 09-10-2012 at 02:42 PM. Reason: was in wrong section.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
Comfortech Show Promo Image

Related Forums

Plumbing Talks | Contractor Magazine
Forums | Electrical Construction & Maintenance (EC&M) Magazine
Comfortech365 Virtual Event