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  1. #14
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    Quote Originally Posted by SandShark View Post
    Doesn't the infinite switch have an internal bi-metal switch in series with the heating element that breaks the connection to the heating element? In the OEM infinite switch, isn't that bi-metal switch rated for 240V? Think about it.
    True the original switch is rated for 240 volts but .... isn't it the amperage that activates the bi-metal switch ?
    Please explain.
    I think the manufacturer uses the higher voltage to cover the end users possible lesser service ie. 208 volt Y Delta vs 240 volt Delta.
    They surely wouldn't want it the other way around.

  2. #15
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    I mistakenly posted that the bi-metal switch is in series with the heating element, though I have seen diagrams that show this to be true. However, Robert Shaw does it differently. Their bi-metal switch has a resistance wire wrapped around it which is connected in parallel with the heating element being controlled and is cycled in unison with the heating element. Nevertheless, the resistance of the bi-metal is designed for 240V, not 208V. That's why there are 208V infinite controls and 240V infinite controls, but there are no 208-240V infinite controls, at least to my knowledge there aren't.

    So, the bottom line is you've got an appliance with heating elements rated for 240V that's running on 208V, which is not a big deal, but you've got an OEM control specifically rated for 240V running on 208V and you're using non-OEM replacement parts.
    With your chrome heart shining in the sun, long may you run.

  3. #16
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    Thanks SandShark
    I found this to be of interest seeing how you brought it up
    .
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  4. #17
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    Quote Originally Posted by VTP99 View Post
    Thanks SandShark
    I found this to be of interest seeing how you brought it up
    .
    Yeah, I did use that to help explain. BTW, whatever happened to Ectofix (Earl)? He could probably explain things a lot better than I did.
    With your chrome heart shining in the sun, long may you run.

  5. #18
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    Quote Originally Posted by SandShark View Post
    Yeah, I did use that to help explain. BTW, whatever happened to Ectofix (Earl)? He could probably explain things a lot better than I did.
    He pops in now and then and he is a Guru when it comes to electrical appliances.
    Personally I try to avoid the hot side because it comes with all its specialties.
    That said I still do it to keep the competition out of my customers door.

  6. #19
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    Quote Originally Posted by VTP99 View Post
    He pops in now and then and he is a Guru when it comes to electrical appliances.
    Personally I try to avoid the hot side because it comes with all its specialties.
    That said I still do it to keep the competition out of my customers door.
    He’s definitely a Guru. I’m trying to convince my buddy, who owns an HVAC/R company, to branch out into the hot side. He has a lot of restaurant customers. I did HVAC/R for decades before I got into the hot side. I wish I had started on the hot side. No attics!
    With your chrome heart shining in the sun, long may you run.

  7. #20
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    Oh, for what it's worth, Hello Cowgirl in the Sand 4-way Street (live) one of my favorites
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  8. #21
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    Quote Originally Posted by SandShark View Post
    Yeah, I did use that to help explain. BTW, whatever happened to Ectofix (Earl)? He could probably explain things a lot better than I did.
    WOW! I wasn't expecting THAT when I opened this thread! Thank you, but I'm still learning TOO!

    Nonetheless - SandShark, I think you pretty well covered it.


    "You never know what others don't know." -

    If I can't laugh at myself...then I'll laugh at YOU! -

  9. #22
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    Quote Originally Posted by VTP99 View Post
    Oh, for what it's worth, Hello Cowgirl in the Sand 4-way Street (live) one of my favorites


    "You never know what others don't know." -

    If I can't laugh at myself...then I'll laugh at YOU! -

  10. #23
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    Quote Originally Posted by ECtofix View Post
    WOW! I wasn't expecting THAT when I opened this thread! Thank you, but I'm still learning TOO!

    Nonetheless - SandShark, I think you pretty well covered it.
    I still dont understand why this new switch cannot work just as well as the old original one. I understand Sandsharks view that the original has to go back in but hear me out here please(I am big on oem replacements too, when they work).

    There was three reasons why I put a different control in:

    1. Customer needs it working over the weekend

    2. The original control, element, fiberglass wires, and fuse were replaced by me just 2 months ago and I have had two call backs on it already. The last time I went there, I turned it on and there was no voltage coming out to h1 and h2 , even though l1 and l2 had power with the element cold and switch turned on. So I pressed on the little button in the middle of that original robert shaw switch and it started working. Four weeks later, Callback again this saturday saying the switch is acting up. It works sometimes and not other times. So I knew going in that was the problem and indeed it was.

    3. I was told in the past that these infinite switches implode on itself if it receives lower voltage than what its rated for and it will only work on the "hi" setting. This unit only applies 208 v to these 240v oem switches which I believe is destroying them.


    Hence the reason why I decided that I am going to try this new switch(208v 13 amp) that is used for 208v hatco heat lamps that run 800 watt heating element. And it should be sufficient to run a 1750 watt heating element according to Ohms Law.


    My question is, If I go and get another 240v 15 amp control again and apply 208v to it, isn't it a matter of when it will fail as opposed to if it will fail?

    I think the whole issue here is voltage related, What are your guys opinions?

  11. #24
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    Quote Originally Posted by Rockwell View Post
    I still dont understand why this new switch cannot work just as well as the old original one. I understand Sandsharks view that the original has to go back in but hear me out here please(I am big on oem replacements too, when they work).

    There was three reasons why I put a different control in:

    1. Customer needs it working over the weekend

    2. The original control, element, fiberglass wires, and fuse were replaced by me just 2 months ago and I have had two call backs on it already. The last time I went there, I turned it on and there was no voltage coming out to h1 and h2 , even though l1 and l2 had power with the element cold and switch turned on. So I pressed on the little button in the middle of that original robert shaw switch and it started working. Four weeks later, Callback again this saturday saying the switch is acting up. It works sometimes and not other times. So I knew going in that was the problem and indeed it was.

    3. I was told in the past that these infinite switches implode on itself if it receives lower voltage than what its rated for and it will only work on the "hi" setting. This unit only applies 208 v to these 240v oem switches which I believe is destroying them.


    Hence the reason why I decided that I am going to try this new switch(208v 13 amp) that is used for 208v hatco heat lamps that run 800 watt heating element. And it should be sufficient to run a 1750 watt heating element according to Ohms Law.


    My question is, If I go and get another 240v 15 amp control again and apply 208v to it, isn't it a matter of when it will fail as opposed to if it will fail?

    I think the whole issue here is voltage related, What are your guys opinions?
    There you go! Look, I am not an engineer and I am not an infinite control expert, but this is what I think based on researching this issue after I read your post. Beforehand, I really couldn't tell you specifically how the internals of of infinite switch actually worked. But, this is my understanding of what's going on with your issue.

    The Hatco bi-metal switch circuit resistance has different resitance because of the application it's being used for, which is a heat lamp. It has nothing to do with the wattage (amp) rating of the control, but has everything to do with the voltage going to the bi-metal switch circuit. That's what controls the heating element. Remember, too, depending on which way the knob (internal cam) is turned, it is applying more or less force to the magnetic contacts of the bi-metal switch. As the bi-metal heats up and starts warping, it is trying to overcome the force of the magnetic contacts. Not only is the resistance of the bi-metal engineered for the application, so are the magnetic contacts engineered for the application. The Hatco control and its bi-metal switch components are not engineered for that application, which is heating water to boiling with a 1750 watt 240V heating element, and the OEM control and its bi-metal switch components are not engineered to work properly with 208V.

    Anyway, this is my understanding and take of what is going on with the issue you're having. I could be way off base, but I think I'm in the ballpark. If someone else has a better understanding and explanation, I would appreciate reading it. ECtofix, are you out there?
    With your chrome heart shining in the sun, long may you run.

  12. #25
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    Lower voltage through an element with the same resistance = less heat. That infinite control should stay on longer rather than shorter.

    Amperage rating of the infinite control = How much current the contacts can take.

    How is the switch wired and oriented? I would suspect you've got a wire crossed somewhere which is causing a high amperage draw on the switch.

    Sent from my SM-G960W using Tapatalk

  13. #26
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    It is a resistive load on the bi-metal. I agree it should respond slower due to the lower voltage.
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