The boil kettle is electrically heated with a 4,500 W element, and is essentially the same as the HLT, albeit more beat-up (it's an older keg). There is a thermowell that a type T thermocouple is inserted that measures the temperature for a PID that then cycles power to the heater element. The couplings for the heater element and thermowell are welded onto the keg (1" and 1/4" NPT half couplings, respectively). The thermowell is a custom-made 1/4" stainless steel piece of tubing (approximately 15" in length) that has the end crimped and TIG welded, and is then welded to onto a 1/4" male NPT x 1/4" compression fitting. The compression fitting was bored out to allow the 1/4" SS tube to extend all the way through. This thermowell is screwed into the coupling and sealed with teflon tape. The kettle drain is a weld-free bulkhead coupling that is sealed with silicone o-rings. This has a 1/2" stainless steel tubing attachment on the inside that is bent such that the opening is at the center, bottom part of the keg. Only 1/4 cup or less water is left after fully draining the system. The outside of the bulkhead coupling is a 1/2" NPT male connection with a 1/2" full port stainless steel ball valve.
During the final part of the boil, the hot wort is usually recirculated through the pump and whirlpool component of the immersion chiller to sanitize all the insides. If whole hops are being used, a false bottom is applied. If pellet hops are used, there is no filtration, as the pellet hops will pass through the pump with no problems.
12 gallons of RT water can be heated to strike temperature (roughly 165 °F) in approximately 30-40 minutes. However, due to water temperature stratification, the water has to be stirred on occasion to ensure even heating of the water. Once heated, the water is transferred by gravity to the mash tun with grain. More water is then added for heating to the mash-out and sparge temperature. There is no water level monitor, so the power is always turned off when draining any liquid to avoid overheating and burning out the heater element.
Note that I do not call this a keggle or e-keggle. I have a strong dislike for that portmanteau.