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  1. #1

    Heat strip sequencer

    I think I have a bad sequencer, but I'm not 100% sure how they work.
    It is receiving 24 volts and has 240v coming in one side, but not on the other side ( connected to strips ).
    Can anyone explain to me how they are supposed to work?

  2. #2
    Join Date
    Jan 2010
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    Quote Originally Posted by Honesttech View Post
    I think I have a bad sequencer, but I'm not 100% sure how they work.
    It is receiving 24 volts and has 240v coming in one side, but not on the other side ( connected to strips ).
    Can anyone explain to me how they are supposed to work?
    More like 120 on one side of strip and 120 going thru sequencer then other side of strip.

  3. #3
    Join Date
    Mar 2010
    Location
    Kent, WA.
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    189
    somebody correct me if im wrong but this is how they should work. the 24v signal heats up a bi-metal strip inside the sequencer. the heating of the strip makes it into a switch basically. sequencers have time ratings to switch on. basically they are used to trigger the heat strips in different intervals. this way you have lets say a 30kw heat strip and your sequencers would bring on 10kw and then some time later another 10kw and again some time and your last 10kw. this is the basic design and it keeps from 30kw in this example from coming on at one time, decreasing your demand charge from the utilities and dimming the lights.
    Experience
    Is what you get when you didn't get what you wanted.

    A positive attidude will not solve all your problems, but it will annoy enough people to make it worthwhile.

  4. #4
    Join Date
    Jul 2007
    Location
    Virginia
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    Quote Originally Posted by Honesttech View Post
    I think I have a bad sequencer, but I'm not 100% sure how they work.
    See attachment.
    Attached Images Attached Images
    Instead of learning the tricks of the trade, learn the trade.

  5. #5
    Thank you. That's exactly what I was wondering, is what closes that switch?
    And it is 240v going into the sequencer, but not coming out.

  6. #6
    Join Date
    Mar 2012
    Location
    Connecticut
    Posts
    43
    Thank you very much for the file.

  7. #7
    Well, looks like I screwed up all over the place on this one. My lack of knowledge on sequencers was quite obvious here. I wasn't even right about the high voltage. It turned out that the 24 volt common was connected to the wrong 24 v side of the contactor coil. So, basically the sequencer had no common. Thats it.
    Lesson learned...... the embarrassing way.

  8. #8
    Join Date
    Feb 2012
    Location
    Alabama
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    378
    Quote Originally Posted by Honesttech View Post
    Well, looks like I screwed up all over the place on this one. My lack of knowledge on sequencers was quite obvious here. I wasn't even right about the high voltage. It turned out that the 24 volt common was connected to the wrong 24 v side of the contactor coil. So, basically the sequencer had no common. Thats it.
    Lesson learned...... the embarrassing way.
    Lessons learned the embarrassing way are usually not forgotten. One tip on the high voltage, you may already know and if so just disregard. If you measure voltage across a switch it is most likely open. Can turn power off and remove the high voltage wires, then turn power back on and use ohm meter to be sure.

  9. #9
    Join Date
    Aug 2007
    Location
    Northern VA 38 degrees N by 76 degrees W
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    5,060
    Quote Originally Posted by Tech it out View Post
    Lessons learned the embarrassing way are usually not forgotten. One tip on the high voltage, you may already know and if so just disregard. If you measure voltage across a switch it is most likely open. Can turn power off and remove the high voltage wires, then turn power back on and use ohm meter to be sure.
    "turn power back on and use ohm meter"?

  10. #10
    Join Date
    Feb 2012
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    VA
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    109
    Quote Originally Posted by rundawg View Post
    See attachment.
    you can allways count on rundawg

  11. #11
    Join Date
    Feb 2012
    Location
    VA
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    109
    cool
    Attached Images Attached Images

  12. #12
    Join Date
    Feb 2012
    Location
    South Georgia
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    Quote Originally Posted by rundawg View Post
    See attachment.
    actually there is a ceramic post that sits on top of the bi-metal disc, when the disc is heated it "clicks" changing shape from converse to convex pushing the ceramic post up and closing the circuit. on double stack seq. there are two discs , one for each switch, the difference is the two bi-metal discs have different temps and convex angles. take a bad one apart and examine it, you will see what im talking about. seq. is a bad design due to its thermal reactance and intermittent operation

  13. #13
    Join Date
    Feb 2012
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    Alabama
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    Quote Originally Posted by second opinion View Post
    "turn power back on and use ohm meter"?
    Nope now that wouldn't hardly work would it? But if you removed the high voltage wires with the power off, then turned the power back on like I wrote, it would work like a charm with an ohm meter now wouldn't it?

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