Re: Gas Pilot Sensor

[Frank Olson <Use_the_email_links@xxxxxxxxxxxxxxxxxxxxxx>]

Frank Winans wrote:
> "R-Guy" wrote
>
>>I would like to monitor the pilot in my gas-fueled boiler system
>>at home so that I can raise an alarm when it gets blown-out
>>by the wind.  Is there a special thermocouple-type-device for
>>this type of application?
>>
>>
>
> Not sure, but they describe a kit that detects 'blown-out' and
> also produces sparks to relight the pilot at web page
> http://toad.net/~jsmeenen/relight.html
> so I assume you could get one of those and build something
> like you want from the detector front-end part.
>
> I know it's a pain to build a project using standard thermocouples
> because they give you like 30 millivolts, tops, so you need really
> really big metal {and tightly connected} fittings to avoid high
> resistance.
> But that same web site describes a somewhat rare
> 'Millivolt Thermo-pile' thermocouple,
> http://toad.net/~jsmeenen/gasvalve.html
> and whoah, it turns out my house uses one in this
> ancient {circa 1970's?} in-wall gas furnace, so I slapped
> a vom on it and it puts out a full 300 millivolts under load!
> This voltage is high enough that it has just a regular pair of wires
> dangling out the end, and spade terminals on those wires,
> instead of a screw-on coaxial design.  If you can find a source
> for that part, you should be able to design or hire
> a repairman {or ham radio operator} to design an interface circuit.
>
>


We call that "bassifying" a solution.  It'll involve about fifteen
relays and a Napco LCD keypad programmed to read "Attention Burglar. Go
ahead, make my day."