Results 1 to 5 of 5
  1. #1
    Join Date
    Sep 2011
    Posts
    58

    Circuit board keeps shorting out...

    I recently serviced a split system horizontal 2.5 ton unit (attic) which had a bad circuit board & fan relay. The system itself is kind of old, 8+ years and it really looks like worse than that.
    Anyway, I replaced both components and it worked well for a couple of weeks then I get the call, the evaporator fan is not running again..
    I get there to find the circuit board and relay had gone out again due to humidity, the circuit board looked in pretty bad shape. I have checked the evaporator and it doesn't seem air flow is an issue.
    .
    What is the best way to prevent this from happening again?
    I've even thought of mounting the circuit board outside the air handler but I'm not sure. or just bypassing the circuit board?

    What do you guys think?

  2. #2
    Join Date
    Mar 2007
    Location
    southeast u.s.
    Posts
    71
    Due to humidity or is water getting to it? You'd have to find out exactly why the board is shorting out and address that particular issue. Sounds like the board failure is a symptom of another problem. Maybe there is an intermittent short in the low voltage circuit, maybe the unit needs to be insulated, who knows...

  3. #3
    Join Date
    May 2004
    Location
    Frederick, MD
    Posts
    920

    If

    it ran for 8 years and is now starting to eat circuit boards, something has changed. You will have to be like a detective and go over the system. Blower motor drawing too many amps, etc.
    GO NAVY, BEAT ARMY!

    A DECADE OF DOMINANCE! +2

  4. #4
    Join Date
    Apr 2008
    Location
    Maryland
    Posts
    18
    Take some plexiglass and use it in place of the door. That way you can see what's going on in the unit under normal running conditions. I keep all couple different size peices on the truck. Comes in handy for these kind of issues and coil icing.

  5. #5
    Join Date
    Nov 2006
    Location
    Southeastern Pa
    Posts
    17,825
    If the board is:

    inside the air handler

    exposed to the airflow

    and downstream of the evaporator

    then I'd say that you have a clogged evap and water is being pulled off the coil and is dousing the board. It's called carry-over.
    [Avatar photo from a Florida training accident. Everyone walked away.]
    2 Tim 3:16-17

    RSES CMS, HVAC Electrical Specialist

    AOP Forum Rules:







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