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  1. #14
    Join Date
    Jul 2002
    Location
    SE Texas
    Posts
    461
    How badly were the coils iced up. Was the ice uniform and covering all the coil or was the ice covering one or two particular areas of the coils? I ask because, if there are issues with the refrigeration part of the system (low charge, superheat issues, etc.), excessive ice can build up in the areas closest to the expansion valve rather than uniformly across the evaporator. When this happens, since the defrost termination Klixon is located on the opposite end of the coils, the ice nearest the expansion valve will not thaw and, eventually, will keep building up over time.

    Once you defrosted the coils and you put it back into defrost, it is normal for the defrost to terminate before the time clock terminates the defrost. As mentioned, that's what defrost termination is supposed to do.
    With your chrome heart shining in the sun, long may you run.

  2. #15
    Join Date
    Oct 2011
    Location
    Chicagoland Area
    Posts
    4,855
    ...and by adding hot water to the equasion you were unable to determine if the defrost termination switch is bad. If the switch is shorted out, it may have let the magic smoke out of the solenoid on the clock.
    Officially, Down for the count

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  3. #16
    Join Date
    May 2009
    Location
    The Pas, Manitoba Canada
    Posts
    231
    Disconnect X on the timer for a temporary check of defrost sequence, heaters etc. Is it only defrost termination at the klixon or fan delay too?

  4. #17
    Join Date
    Feb 2006
    Location
    USA
    Posts
    4,381
    I stick the small bead from my k type thermocouple right under the termination switch & ensure its secure. I then cycle into defrost & look at the temp. I watch a few cycles. All this mention of defrost termination is great but you also need to check the heater limit. Do it the same way i mention above. Ohm it out cold & warm also. I'm to the point i change these as a set now when one is bad

  5. #18
    Join Date
    May 2003
    Location
    Utah
    Posts
    743
    I've seen the defrost timer pins so worn that they no longer initiate a defrost cycle. Easy thing to check and confirm or deny it as a problem.

    The bottom of the pin should be round.

  6. #19
    Join Date
    Mar 2008
    Posts
    257
    Quote Originally Posted by hvactech88 View Post
    working on a walk-in freezer with a heatcraft evap, both coils are iced up found the clock set to noon, its 6 oclock threw it into defrost manually, tested electric heaters all working fans turn off the way they should deiced coils completely with the help with using hot water to speed process up. Defrost clock set to 40 min defrost, but would come out of defrost before then before the 40 minutes. time clock motor is working and moving ahead, so trying to figure if it is was the clock got stuck or could the defrost termination kilxon be no good and throwing it out of defrost to soon.
    The time on a clock is not a sign of trouble to start with, a power failure or a service tech testing the defrost would explain the incorrect time. As I read it you put it in a defrost and then you proved termination was working with hot water. No problems there...

  7. #20
    Join Date
    Jan 2010
    Posts
    6,838
    Quote Originally Posted by hvactech88 View Post
    i had 120v on x when it was out of defrost
    If it's a 120 volt clock you will have 120 there at X. It is passing thru the coil all the time. The wire attached to X is what provides neutral to that coil.

  8. #21
    Join Date
    Oct 2011
    Location
    Chicagoland Area
    Posts
    4,855
    Quote Originally Posted by VTP99 View Post
    If it's a 120 volt clock you will have 120 there at X. It is passing thru the coil all the time. The wire attached to X is what provides neutral to that coil.
    Depends on the clock configuration. An 8145 is configured with X energizes the termination solenoid. The 8045 doesnt have a solenoid and X is neutral
    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

  9. #22
    Join Date
    Jan 2010
    Posts
    6,838
    Quote Originally Posted by 2sac View Post
    Depends on the clock configuration. An 8145 is configured with X energizes the termination solenoid. The 8045 doesnt have a solenoid and X is neutral
    Yes this is true but i thought we were talking about a clock with a solenoid. Good point maybe he doesn't have a solenoid. What's he doing with a termination then ?

  10. #23
    Join Date
    Mar 2011
    Location
    Somewhere or nowhere
    Posts
    32
    First thing you should do when you find an iced up evap coil is mark the time clock to ensure it is spinning. I have seen them stick and then when manually turned they work for a few days again. Not saying this is your issue here, but it will be one day.

  11. #24
    Join Date
    Nov 2007
    Location
    Mississippi
    Posts
    1,401
    Quote Originally Posted by badgerland01 View Post
    First thing you should do when you find an iced up evap coil is mark the time clock to ensure it is spinning. I have seen them stick and then when manually turned they work for a few days again. Not saying this is your issue here, but it will be one day.

    I too have seen this several times. I'd bet you got a bad clock.

  12. #25
    Join Date
    Jan 2006
    Location
    DFW Metroplex
    Posts
    4,910
    Quote Originally Posted by hvactech88 View Post
    working on a walk-in freezer with a heatcraft evap, both coils are iced up found the clock set to noon, its 6 oclock threw it into defrost manually, tested electric heaters all working fans turn off the way they should deiced coils completely with the help with using hot water to speed process up. Defrost clock set to 40 min defrost, but would come out of defrost before then before the 40 minutes. time clock motor is working and moving ahead, so trying to figure if it is was the clock got stuck or could the defrost termination kilxon be no good and throwing it out of defrost to soon.
    As has been mentioned earlier, it seems you went ahead and took care of the issue without making a determination as to the cause.

    If you defrosted the coil with hot water and then ran it into defrost to check the overall operation - the termination klixon should kick the system out of defrost before the 40 minute failsafe (after all, the coil is completely clear, right?).

    At this point, if it were me, I'd make it a priority to stop back in the next few days to check the coil condition, defrost set pin condition, and verify whether or not the termination klixon is operating properly after a few days of run time under its belt.
    "The problem is the average person isnt tuned in to lifelong learning, or going to seminars and so forth. If the information is not on television, and its not in the movies they watch, and its not in the few books that they buy, they dont get it" - Jack Canfield

  13. #26
    Join Date
    Jul 2011
    Location
    St. Louis
    Posts
    123
    Although we are all very comfortable with mechanical timeclocks, with the progress in electronics and the level of control and flexibility they offer, I think the days of mechanical defrost clocks are numbered, no pun intended.
    Think of the improvements in settting, efficiency and power electronic fuel injection has over mechanical carburetors.
    In an infinite universe, not only are all things possible, all things are necessary

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