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  1. #1
    Join Date
    Mar 2005
    Location
    Toronto, Ontario. Canada
    Posts
    93
    I was at a school today that has about 70 of these boxes. Four of them have a AS-VAV111-1 controller. Its control transformer fuse 2.5amps was blown. I checked for shorts to ground found nothing. Replaced fuse and they started up. Each box has its own transformer incase anyone is wondering.
    I watched the actuator for the HW coil travel and watched the travel of the damper actuator. Fuse still did not pop.
    Is this common?
    What should i be looking for?
    I noticed on one VAV the AS-VAV111-1 LED was on continuous no flickering?
    Any help is appreciated.

  2. #2
    This (comm bus LED on steady) indicates your zone bus is shorted to ground or 24v... This is also likely the source of your blown fuses. Check your zone stat and associated wiring carefully.

  3. #3
    Join Date
    Mar 2005
    Location
    Toronto, Ontario. Canada
    Posts
    93
    Does it still hold true if when the fuse is replaced and does not blow again. The other VAV's that blew a fuse have a flickering LED. Would you be able to get deeper on your explanation or is that just the way it is and that is the only reason to explain this mysterious blown fuses scenario?
    The installation has been about 10yrs plus. I was unalbe to ask the custodian if this blowing fuses intermittently is an ongoing problem with their boxes throughout. He was away sick.
    Thanks for the reply.


    [Edited by chill factor on 04-15-2005 at 07:53 PM]

  4. #4
    I found that explaination in Techlit, my take on it is that because you can use the zone stat jack to communicate on the bus, a shorted conductor in the zone bus wiring will prevent communication. Is this a stand alone controller or is it on an N2 bus? Check to see if you have comm on the N2 to this controller. Do they use the zone bus wires that look like phone cord or are they hardwired? The phone cord looking ones can deteriorate internally and short, if they are hardwired I would check for rub-through anywhere they rest on metal... my favorite is the guy who makes all his wiring look really neat by binding it tight to metal studs with tie wraps! For the fuse blowing, you might have an intermittant path to ground related to the zone bus short, like a rub through. Where is this fuse located? Is it an OEM built with the box? IIRC, asc's aren't fused on the board. Good luck, let us know what you find.

  5. #5
    Join Date
    Apr 2005
    Location
    Pennsylvania
    Posts
    41
    control_noob hit the nail on the head, he is absolutly correct with his diagnose.
    I Bleed Johnson Blue

  6. #6
    Originally posted by jciengineer
    control_noob hit the nail on the head, he is absolutly correct with his diagnose.
    Well, hey... thanks.

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