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Circuits designed by David Johnson, P.E.
Last Updated on:
Wednesday, December 20, 2017 06:09 AM
List of Dave's Circuit Designs
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Fireplace Fizzle |
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Problem: Gas fireplace won't turn always turn on consistently. The pilot light was always on. As illustrated below, a typical gas fireplace has a small pilot light flame. 
Over time, the output current from the thermopile would degrade to a point where it would no
longer produce enough current to turn on the valve. |
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| Solution: The long term solution would be to replace the thermopile.
But, in the short term, the modification below would keep the thing going for another year or two.
As shown below,
the solution was to connect a supercapacitor across the thermopile. This device acts like
a battery and would provide the needed peak current to open the valve. A 4.7 farad device was sufficient. |
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List of
Dave's
Circuits
List of Circuits from DC Magazine
eMail David A.
Johnson, P.E. about this circuit
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DC Magazine, Issue 4, Page 7: Fireplace Fizzle |
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