Results 1 to 5 of 5
  1. 09-10-2012, 10:05 AM #1
    hobbit
    hobbit is offline Regular Guest
    Join Date
    Feb 2012
    Posts
    42
    Post Likes

    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*
    Reply With Quote Reply With Quote
  2. 09-10-2012, 12:30 PM #2
    Shophound's Avatar
    Shophound
    Shophound is offline Professional Member*
    Join Date
    Aug 2003
    Location
    Fort Worth, TX
    Posts
    11,733
    Post Likes
    What indicates that this is what the set of dry contacts are for? Dry contacts are often for alarm triggering purposes.
    Building Physics Rule #1: Hot flows to cold.


    Building Physics Rule #2:     Higher air pressure moves toward lower air pressure


    Building Physics Rule #3:     Higher moisture concentration moves toward lower moisture concentration.
    Reply With Quote Reply With Quote
  3. 09-10-2012, 12:40 PM #3
    ryan1088's Avatar
    ryan1088
    ryan1088 is offline Professional Member*
    Join Date
    Mar 2009
    Location
    Mid-Mo
    Posts
    3,600
    Post Likes
    Hobbit it this on your Daikin system we have talked about before?
    Reply With Quote Reply With Quote
  4. 09-10-2012, 02:03 PM #4
    hobbit
    hobbit is offline Regular Guest
    Join Date
    Feb 2012
    Posts
    42
    Post Likes
    Thread Starter
    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*
    Reply With Quote Reply With Quote
  5. 09-10-2012, 02:20 PM #5
    Elfshadow
    Elfshadow is offline Professional Member
    Join Date
    Sep 2012
    Location
    USA
    Posts
    1,085
    Post Likes
    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.
    Reply With Quote Reply With Quote
« Previous Thread | Next Thread »

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  

Forum Rules
Contracting Business

Related Forums

Plumbing Talks | Contractor MagazineThe place where Electrical professionals meet.
HPAC Engineering