Thermocouple - Robert ShawThis is one of the two common pilot powered generators to operate gas stove valves. Here is an overview of their functions.The tubing connector on this part is 24 inches long. 750 Millivot Thermopile - Fits the vast majority of gas stoves. This is the single power generator on the older Robertshaw 7000 series valves and the second and larger generator on the newer and more common Nova Sit 820 valves. This generator powers the main burner valve by directing enough power to the solenoid magnet valve assembly to allow gas to flow to the burner when the on switch or wall thermostat makes contact, calling for heat. To be functional this generator needs the pilot flame to engulf the top 1/3 of the thermopile and deliver 375 or more millivolts to the valve while at standing pilot position, measured at the inner and one outer wire connection to the valve marked TP. More trouble shooting and technical data is available thru stove manuals and technical manuals that we can supply. Check the owners manuals section of our site in the upper left corner as we are adding more information here all the time. The smaller generator, when two are present, is the thermocouple and it generates up to about 29 millivolts but 19 is usually an operating output. This generator powers the pilot light valve only and must also have the tip engulfed in flame to operate. Soot on either generator or incomplete flame contact will keep them from operating properly or cause intermittent operation. Having a stove not respond to thermostat but succeed in responding to the on/off switch on the stove is the first warning sign that the millivolt output is dropping near the threshold for operation. We caution customers to imediately resolve the issue as it will only get worse when you need it the most. These parts may also be called Thermapiles, Thermacouples, Pilot generators, Millivolt generators, power supplies, etc. so we list them here to allow this page to be found in a search.