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  1. #1
    Join Date
    May 2013
    Posts
    47

    Walkin cooler not maintaining temperature and evaporator coil freezing up

    Using penn thermostat m#a19aba-40.
    What brand of thermostat a few years ago that would go bad after just a couple of months in use?

  2. #2
    Join Date
    Oct 2009
    Location
    Raleigh, NC
    Posts
    799
    Lots of all kinds of things go bad after just a few months of use.

    Is that the problem for sure?

  3. #3
    Join Date
    May 2013
    Posts
    47
    No the main problem is that the door is bad and is left open all the time. We just change the system over from the Beacon one system to mechanical system. After I changed over to mechanical system I had to install a defrost timer to keep it from freezing up. no ice on the coil after the defrost timer was installed . I'm having a hard time getting the thermostat dialed in I don't know if its the owner changing the temperature or if its a the thermostat

  4. #4
    Join Date
    Sep 2010
    Location
    Western, MO
    Posts
    871
    If you don't fix the door and get them to keep it closed, you'll never win this one.

    jim
    Common sense isn't very common anymore.

  5. #5
    Join Date
    May 2013
    Posts
    47
    You got that right!

  6. #6
    Join Date
    May 2013
    Posts
    47
    Would a thermostat that senses the coil temp be better suited for this application?

  7. #7
    Join Date
    Oct 2011
    Location
    Chicagoland Area
    Posts
    4,760
    You've already installed a defrost clock. IMO, no need for a coil sensing tstat. Providing the refrigeration is correct. Install an A419. The sensor line is long enough you can hide the controller and lock it out.
    Officially, Down for the count

    YOU HAVE TO GET OFF YOUR ASS TO GET ON YOUR FEET

    I know enough to know, I don't know enough
    Liberalism-Ideas so good they mandate them

  8. #8
    Join Date
    May 2013
    Posts
    47
    What is a a419

  9. #9
    Join Date
    Jul 2011
    Location
    Lehigh Valley, PA
    Posts
    471
    Quote Originally Posted by Rheeman View Post
    What is a a419
    Johnson Controls A419.

    I just bought one today for my problem child walk in....no defrost timer either. I think I better add that into the mix. This box has two separate condensing units and evaps that was connected to a Penn dual switch. The Penn was staying closed. I will use the 419 and a DPDT relay to control the pump down circuit along with the timer.

  10. #10
    Join Date
    Nov 2010
    Location
    Missouri
    Posts
    369
    Links to direct purchase sites are not permitted in he open forums.
    Last edited by beenthere; 07-21-2013 at 06:51 PM. Reason: removed link to direct purchase site

  11. #11
    Join Date
    May 2013
    Posts
    47
    I was considering using a coil sensing stat and shorting the defrost to a minimum

  12. #12
    Join Date
    Oct 2011
    Location
    Chicagoland Area
    Posts
    4,760
    Any mechanical stat can be used as a coil sensing stat providing you set the differential properly. The clock is already there. The a419 is similar in price, but takes a little more in the wiring install. It's going to be more accurate than a mechanical stat. If it were me, install the a419 and set the clock to defrost for 1hr at midnight and (2) 30 minute defrosts at 8hr intervals. You might even be able to get rid of the 30min defrosts. Trial and error.
    Officially, Down for the count

    YOU HAVE TO GET OFF YOUR ASS TO GET ON YOUR FEET

    I know enough to know, I don't know enough
    Liberalism-Ideas so good they mandate them

  13. #13
    Join Date
    Jan 2010
    Location
    Vancouver Island
    Posts
    409
    I agree a A419 would be a good choice. No one will be able to figure out how to unlock the controls and mess with them without finding an install manual.

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