Re: Gas Pilot Sensor

["Frank Winans" <fwinans@xxxxxxxxxxx>]

"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.