The HLT, hot liquor tun or hot liquor tank, is where the brewing begins. This is the tank used to heat water. That's all it does. In order to make beer you need to have a certain volume of water at a certain tempterature. A 20 gallon stainless steel kettle is used for the hlt. It has an accurate site glass to measure water volume. It is heated by a 5500watt 240volt electric heating element controlled by a PID (proportional–integral–derivative) controller. Basically it's a fancy temperature controller that regulates the water temperature. The pid has a temperature sensor inside the HLT measuring the temp. By setting the temperature on the pid, the water temperature is directly controlled. The pid switches the element on and off thru a ssr, or solid state relay. Since electric heat is used there can be a problem with temperature separation. Basically the water heats so fast next to the element it will separate and cause a hot spot and a cool spot in the tank. To fix this, simply recirculate the water while heating. This ensures a perfectly even temperature throughout the tun.
The HLT and Kettle are on a commercail stainless vent hood/grill stand that I salvaged from a closed pizza restaurant. The vent hood removes steam as the water is boiled and holds the pots quite nicely. The stand also houses the electronics used to run and control the HLT, kettle, and pumps.
Once the water is heated to strike temperature in the hlt, it is pumped over to the Mash Tun.