How to wire defrost heaters on a walk in cooler freezer. DTFD fan delay and heater limit switch bypassed on evaporator coil. Bad A19 thermostat, WIC down . Walk in cooler with multiple issues.

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42 thoughts on “HVAC Refrigeration: Walk In Cooler down and wired incorrectly.

  1. matt scott says:

    What's up bro, hey I'm a rookie refrigeration tech too, plenty of commercial HVAC tho… My question to you is, if that is a medium temp box, do they really need a electric defrost? Could you not just take that out for the time being untill you troubleshoot the DTFD and high limit safety and let it do a off-cycle air defrost?
    Thanks for getting in the YouTube game and making these videos, they really help newbie techs like me!!

  2. Martin Woods says:

    You are doing a GOOD JOB showing and representing the HVAC/Refrigeration Industry…. Showing the Good, Badd and Ugly… There are so many different avenues one can choose when you come into this field…
    I myself do the same job you are doing in Atlanta, Ga… We take care of Publix, Kroger, Save Alots, primarily…. That on call is a bitch, but part of the job…. But I always recommend people that ask me about the field togo into Refrigeration because you going to do Air Conditioning also….

  3. icemeister says:

    Sorry I'm late to the party, but I noticed you were looking at the wrong wiring schematic for this evaporator setup. Heatcraft provides a number of different diagrams, one which specifically addresses when there are contactors in the condensing unit for the fans and defrost heaters. The one you needed should have been one the other diagrams on the unit. Here it is in their systems installation manual at the bottom of p.25:

    The way it was wired was basically correct per the schematic, but it looks like they messed up the wiring of the terminator because it (obviously) wasn't working.

    This diagram also shows how that heater limit t'stat was supposed to be connected.

    Hopefully this may help the next time you find this kind of mess. 😉

  4. Greg M says:

    Condenser on roof for coolers had timers, no heaters. So was it suppose to air defrost? Managers complaining the box temp would rise at various times . I remove time clocks from circuit and have not had a problem for 16yrs. Fans run constant . Temps always perfect.

  5. Mario Morua says:

    Rookie Refrigeration, just wondering. If you would have just disconnected all heaters and left fans powered up to run continuously, could that have done it as the complete fix? The defrost timer is working correctly, or maybe could have added or taken off some time.

  6. Guillermo Willy Bianchini says:

    I live here in LA for the last 5 years and when I need to learn new concepts I can learn it much better in spanish (my first language) I don't know how but if you find the way to make bilingual videos or you create a second channel I will subscribe for sure. I do AC for 4 years and refrigeration for 1 ½ years both commercial and always try to learn more and more. But I know I could be better if I learn it in spanish, unfortunately I came to late when I was 30. Gracias hermano! Sos muy buen técnico

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