Page 1 of 2 12 LastLast
Results 1 to 13 of 21
  1. 12-09-2011, 06:52 PM #1
    MarkInMd
    MarkInMd is offline New Guest
    Join Date
    Dec 2011
    Posts
    5

    Pop goes the fuse

    This morning I woke up to a cold bedroom. When I went over to the thermostat the screen was completely blank. This system is a Carrier heat pump system that supplies the top floor of our home. I checked all the CB's on the panel. The indoor unit is in the attic so I went up there to start troubleshooting. I confirmed voltage on the back sides of the four fuses where power enters the unit. and eventually made my way up to the circuit board where I discovered a blown 5 amp fuse. I drove to the auto parts store and bought a pack of 5 fuses. I replaced the fuse, powered up the system and everything seemed fine for about two minutes, then the new fuse blew. I tested the voltage from the transformer and although it was a little high (28 volts) it was steady as a rock. I check all the the connections and looked for anything that may be shorted but everything looks fine. I replaced the fuse again, powered up the system and went down to the thermostat. I set the fan to ON and it came on. Great. I put it back to AUTO and switched the mode from AUTO to HEAT and set the temp for 76. The system said "Wait" for a few minutes and then the screen went blank again. Another blown fuse.

    Do you think there is a problem with the compressor and it's overloading the circuit? One of our outdoor units had been making a bit of a "whining" sound when the compressor would activate this summer but I hadn't had time to figure out which one it was and determine if it was a problem.

    If it's serious I don't mind calling in the pro's. I just want to make sure I've covered all the simple stuff so I don't pay $150 to tighten a screw or replace a fuse...again.

    Thanks!
    Reply With Quote Reply With Quote
  2. 12-09-2011, 07:05 PM #2
    beshvac's Avatar
    beshvac
    beshvac is offline Professional Member*
    Join Date
    Jun 2006
    Location
    Richmond, VA
    Posts
    2,269
    It's not the Brand with the fewest repairs-It's all in the install!!! Attention to detail and using the best materials!
    Reply With Quote Reply With Quote
  3. 12-09-2011, 07:09 PM #3
    cartercrew's Avatar
    cartercrew
    cartercrew is offline Professional Member*
    Join Date
    Jul 2004
    Location
    Charleston, SC
    Posts
    930
    Consider the simple stuff effectively covered. Sounds like a component in the outdoor unit has failed, when the thermostat sends power to energize the condensing unit it shorts out and blows the fuse. Count yourself lucky the fuse is protecting the transformer. Call a local pro and tell them what is going on.
    "Customer Service" is not a department, it's an attitude!
    ???
    Reply With Quote Reply With Quote
  4. 12-09-2011, 07:10 PM #4
    Chris_Worthington's Avatar
    Chris_Worthington
    Chris_Worthington is offline Controls Committee & Global Moderator
    Join Date
    Jul 2007
    Location
    Mount Airy, MD
    Posts
    7,092


    Perhaps try the emergency heat mode in the mid term.
    Controls Forum Rules Site Rules Tridium
    Reply With Quote Reply With Quote
  5. 12-09-2011, 07:17 PM #5
    garyed's Avatar
    garyed
    garyed is offline Professional Member*
    Join Date
    Jul 2009
    Location
    South Carolina
    Posts
    2,093
    Tracking down a low voltage problem like what you described can be tricky even for a pro sometimes so I would not recommend trying to do any more yourself. You obviously have some diagnostic capabilities since you've gone further than most HO's already but its time to bite the bullet, call in the pro & hope it is something simple.
    Gary
    -----------
    http://www.oceanhvac.com
    An engineer designs what he would never work on.
    A technician works on what he would never design.
    Reply With Quote Reply With Quote
  6. 12-09-2011, 07:56 PM #6
    MarkInMd
    MarkInMd is offline New Guest
    Join Date
    Dec 2011
    Posts
    5
    Quote Originally Posted by Chris_Worthington View Post


    Perhaps try the emergency heat mode in the mid term.
    I'm too cheap for that! Since this is just our top floor, I'll just let the heat rise from bottom level. It sounds like I'm going to need the cash savings anyway
    Reply With Quote Reply With Quote
  7. 12-09-2011, 07:57 PM #7
    MarkInMd
    MarkInMd is offline New Guest
    Join Date
    Dec 2011
    Posts
    5
    Why do these things always happen on a Friday?
    Reply With Quote Reply With Quote
  8. 12-09-2011, 08:02 PM #8
    Chris_Worthington's Avatar
    Chris_Worthington
    Chris_Worthington is offline Controls Committee & Global Moderator
    Join Date
    Jul 2007
    Location
    Mount Airy, MD
    Posts
    7,092
    Quote Originally Posted by MarkInMd View Post
    Why do these things always happen on a Friday?
    Assuming your user name indicates your in MD,,, It aint that bad enough yet where the electric heat would kill you through a weekend. Besides it's always best to keep the wifey and kids happy and warm
    Controls Forum Rules Site Rules Tridium
    Reply With Quote Reply With Quote
  9. 12-09-2011, 08:04 PM #9
    ga-hvac-tech
    ga-hvac-tech is offline Professional Member*
    Join Date
    Sep 2005
    Location
    North GA
    Posts
    17,282
    Electrical trouble-shooting in a HP system, is not as easy as it looks... Even us pro's that work on these beasts had to learn... and it took a long time.

    If it were me, I would just bite the bullet and get a tech out. You might find someone that offers regular rates over the weekend... or tough it out until Monday.

    I used to live in Falls Church... the upstairs was not THAT bad when the unit fussed. Might use a plug-in space heater if you really get cold.

    Best to you, hope it is not a major component.
    GA-HVAC-Tech

    Galatians 2:20-21; Colossians 1: 21-22 & 26-27; 3:1-4; Romans Ch's 5-6-7-8

    2 Chronicles 7:14

    Quality work at a fair price with excellent customer service.
    Reply With Quote Reply With Quote
  10. 12-09-2011, 11:16 PM #10
    Cooked's Avatar
    Cooked
    Cooked is offline Professional Member*
    Join Date
    Jun 2011
    Location
    Houston area
    Posts
    1,493

    Thumbs down

    Hmmm, what's interesting is that it runs for a few minutes and then blows the fuse and that pretty much eliminates a short to ground. I have to wonder, does the air handler have an ECM?
    The picture in my avatar is of the Houston Ship Channel and was taken from my backyard. I like to sit outside and slap mosquitos while watching countless supertankers, barges and cargo ships of every shape and size carry all sorts of deadly toxins to and fro. It's really beautiful at times.....just don't eat the three eyed fish....

    ¯`·.¸¸ .·´¯`· .¸>÷÷(((°>

    `·.¸¸..· ´¯`·.¸ ¸.·´¯` ·.¸>÷÷(((°>

    .·´¯`· .¸>÷÷(((°>

    LMAOSHMSFOAIDMT
    Reply With Quote Reply With Quote
  11. 12-09-2011, 11:19 PM #11
    ga-hvac-tech
    ga-hvac-tech is offline Professional Member*
    Join Date
    Sep 2005
    Location
    North GA
    Posts
    17,282
    Quote Originally Posted by Cooked View Post
    Hmmm, what's interesting is that it runs for a few minutes and then blows the fuse and that pretty much eliminates a short to ground. I have to wonder, does the air handler have an ECM?
    Fuse would be control control circuits (low volts)... does that affect the ECM? (Might be going too far with tech advise on an open forum???)

    Probably something wrong in the HP... but best left to a licensed Pro.
    GA-HVAC-Tech

    Galatians 2:20-21; Colossians 1: 21-22 & 26-27; 3:1-4; Romans Ch's 5-6-7-8

    2 Chronicles 7:14

    Quality work at a fair price with excellent customer service.
    Reply With Quote Reply With Quote
  12. 12-10-2011, 12:26 PM #12
    MarkInMd
    MarkInMd is offline New Guest
    Join Date
    Dec 2011
    Posts
    5
    Quote Originally Posted by ga-hvac-tech View Post
    Fuse would be control control circuits (low volts)... does that affect the ECM? (Might be going too far with tech advise on an open forum???)

    Probably something wrong in the HP... but best left to a licensed Pro.
    I've already called the pro's as you guys recommended, but for my own education, What are the ECM and HP? I'm always trying to understand these systems better.
    Reply With Quote Reply With Quote
  13. 12-10-2011, 12:40 PM #13
    Mr Bill's Avatar
    Mr Bill
    Mr Bill is offline Professional Member*
    Join Date
    Dec 2002
    Location
    Houston,Tx.
    Posts
    14,898
    I don't know what I would rather work on, low voltage issues or refrigerant leaks, I don't have a lot more hair to lose.
    “I am glad that I paid so little attention to good advice; had I abided by it I might have been saved from some of my most valuable mistakes.” - Edna St. Vincent Millay

    The critic is a prisoner to his own experiences and perspectives, erroneously believing his limited experiences are the sum of all truth.

    No Guns…No Freedom…Know Guns…Know Freedom.




    Reply With Quote Reply With Quote
Page 1 of 2 12 LastLast
« 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