Results 1 to 9 of 9
  1. #1
    Join Date
    Sep 2007
    Posts
    1
    Post Likes

    Honeywell's "-AC" message

    About a week after the annual inspection on our Lennox furnace we noticed the house was cold and that the Honeywell Chronotherm III was displaying "-AC". The duty officer at the HVAC company guessed this meant that our air conditioning unit wasn't working, which is true, since we don't have one.

    A Google search revealed that this is Honeywell's unhelpful error message for "No AC Power." Voltmeter probes on the R & W screws confirmed this, and I went under the house to find that the maintenance panel interlock switch was cracked and the panel had pushed it out of its mount. Dave Lennox will be happy to know his successors saved a buck on the cheap switch.

    I report, you decide: poor design? Or a careless inspector?

  2. #2
    Join Date
    Apr 2007
    Location
    MN
    Posts
    297
    Post Likes
    I work for a Lennox dealer and recently had a 3 month old Lennox furnace Blower Door Safety Switch fail without the panel ever having been taken off (other than during install). Was the inspection by an HVAC technician?
    S**t or get off the pot!

  3. #3
    Join Date
    Aug 2007
    Location
    MN
    Posts
    2,685
    Post Likes
    not a good one if he didn't know what -ac meant
    You can't fix stupid

  4. #4
    Join Date
    Apr 2007
    Location
    MN
    Posts
    297
    Post Likes
    Quote Originally Posted by cmajerus View Post
    not a good one if he didn't know what -ac meant
    Yeah, "duty officer"? There's a reason he answered the phone...because that's what he does for a living, not fix equipment.
    S**t or get off the pot!

  5. #5
    Join Date
    Jul 2007
    Location
    Beautiful, Philadelphia, the City of Brotherly Love!
    Posts
    1,246
    Post Likes
    Quote Originally Posted by thedaveross;.

    A Google search revealed that this is Honeywell's unhelpful error message for "No AC Power." Voltmeter probes on the R & W screws confirmed this,

    I report, you decide: poor design? Or a careless inspector?
    Actually you would not have 24 volts between R & W, they are the same side of the transformer.

    As to the interlock switch being broken, crap happens, if nothing ever broke we would'nt have much to do.

    I don't think Lennox makes these switches, they are found on other brands.

  6. #6
    Join Date
    Aug 2007
    Location
    MN
    Posts
    2,685
    Post Likes
    Quote Originally Posted by AtticAce View Post
    Actually you would not have 24 volts between R & W, they are the same side of the transformer.

    As to the interlock switch being broken, crap happens, if nothing ever broke we would'nt have much to do.

    I don't think Lennox makes these switches, they are found on other brands.
    they may not make them, but its still a QC problem, one problem I have with Ole Dave, is they wait for the techs to find the issues in the field instead of in the lab. Not that the rest of the industry is perfect, but it seems some just shove new products out on the market too soon.
    You can't fix stupid

  7. #7
    Join Date
    Jun 2004
    Location
    Howell, Michigan
    Posts
    16,162
    Post Likes
    So what? I had a brand new van that didn't make it home from the dealer once...........crap like that happens!

    Oh yea.............how old is that furnace, how many times has that door been on and off?

  8. #8
    Join Date
    Aug 2007
    Location
    MN
    Posts
    2,685
    Post Likes
    Quote Originally Posted by HeyBob View Post
    So what? I had a brand new van that didn't make it home from the dealer once...........crap like that happens!

    Oh yea.............how old is that furnace, how many times has that door been on and off?
    Speaking of van's... We had a new Chebie delivered this summer, co-worker drove it home the 1st night and as he was pulling in the next morning I see the shock was hanging down underneath. the factory must have forgot the nut on the axle housing!!
    You can't fix stupid

  9. #9
    Join Date
    Apr 2007
    Location
    MN
    Posts
    297
    Post Likes
    Quote Originally Posted by AtticAce View Post
    Actually you would not have 24 volts between R & W, they are the same side of the transformer.

    The only time you won't show 24vac on a voltmeter with the leads on R and W is if the tstat were calling for heat. Then you would read 0vac.
    Last edited by HeyBob; 09-19-2007 at 07:49 AM. Reason: Repaired quote
    S**t or get off the pot!

Posting Permissions

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

Related Forums

Plumbing Talks | Contractor MagazineThe place where Electrical professionals meet.