No thermostat in room heaters?

Discussion in 'General Electronics Chat' started by tracecom, Jan 11, 2012.

  1. tracecom

    Thread Starter AAC Fanatic!

    Apr 16, 2010
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    I just read this on-line and was surprised.

    "Most room heaters with a temperature control work by controlling the duty cycle of the heater, which in turn controls the energy output. However, without temperature feedback, it’s up to the user to continually adjust the heater for maximum comfort."

    I thought that all room heaters had at least a bi-metallic thermostat, but not so, according to the quote above. I know that many room heaters do turn off and on based the setting of a rotary control; what causes them to turn on and off if not a thermostat?
     
  2. Adjuster

    Well-Known Member

    Dec 26, 2010
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    I think sometimes they use a bimetallic strip effort heated by a little local element. It's not a thermostat as such, as it does not depend much on room temperature. It produces a sort of crude slow PWM to vary the heat. Similar things are used with electric cooker elements, or used to be, back in the day. Try Googling "Simmerstat".
     
    Last edited: Jan 11, 2012
  3. tracecom

    Thread Starter AAC Fanatic!

    Apr 16, 2010
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    I guess it's semantics, because I consider any switch that automatically turns a heating or cooling apparatus on and off in response to temperature changes to be a thermostat. Granted, some of them are much cruder than others, but thermostats just the same.

    Apparently, not everyone sees it the same as I.
     
  4. strantor

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    Oct 3, 2010
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    where did you pull that quote? Things are different in different areas. When I was in korea the heater in my room definately didn't have a thermostat. You turn the knob up, it gets hot, then hotter, then you wake up in the middle of the night sweating and turn it down, only to wake in the morning to near freezing temps inside. So annoying. had to find the "butter zone" where it was just warm enough to keep the ice devils outside without burning the paint off the walls. but then, if the weather changed, so did the temp inside
     
  5. Brownout

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    Jan 10, 2012
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    It depends on the heater. I have two electric room heaters, and they both have thermostats ( bi-metal switches ) To save on manufacturing costs, some heaters have a simple duty-cycle controller, and you are the thermostat! If you're hot, you turn it down, and visa-versa.
     
  6. tracecom

    Thread Starter AAC Fanatic!

    Apr 16, 2010
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    OK, I finally get it. The switch that turns the heater on and off is apparently time based as opposed to temperature based. But that immediately raises the question in my mind about how the timer works and how that can possibly be cheaper than a bi-metal thermostat.
     
  7. Brownout

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    Jan 10, 2012
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    The strip can also be heated just by the current it passes. I think that's how electric range controls work.
     
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