RIMS heater element bushing selection. To get the correct fit of a RIMS heater element into a threaded bushing (or any other pipe thread), you need some knowledge of the threads and you need to pick the threaded part carefully. Armed with this knowledge, the task is simple. In my estiamation, anyone who does not remove their RIMS heater element after every brew is asking for trouble. Unless you use CIP (Clean In Place) procedures with highly corrosive chemicals, the element needs to be removed and cleaned with a soft bristle brush and hot water to remove the layer of biege goop that collects on it from the grain. If this is allowed to remain, you risk the chance that it will rot and spoil your next batch. This is not idle theory, but in fact happened to me before I realized the necessity of disassembly, cleaning and thorough drying after every batch. Regarding pipe threads, there are two pieces of information necessary. A standard 1.5" x 1" reducing bushing has internal threads of 1" by 11tpi. These threads are NPT (National Pipe Taper) and as the name implies, are tapered. All manufacturing processes have tolerances, and during its manufacture, the bushing may have landed on one end or other of the tolerance limits. Water heater elements utilize 1" x 11tpi NPS (National Pipe Straight) threads. Tapered threads produce their sealing action when the tapered male thread is forced into the tapered female thread and the harder they are screwed together, the tighter the threads mesh. Straight threads have no self sealing action and are generally provided with a rubber gasket to accomplish liquid sealing properties. In all other respects, the straight and the tapered threads are compatible. When you attempt to mate the heater element with straight threads into the pipe fitting with tapered threads, it is important to hand select a fitting which will allow a seal to be created. If the fitting is on the low end of the manufacturer's tolerances, in other words, the tap which created the threads was not driven in fully, chances are very good that the straight threads of the heater will bind in the tapered threads of the fitting before the rubber gasket makes a liquid tight seal. What you need to do when you buy the bushing into which the heater screws is to take the heater with you. Try every bushing they have until you find one that will allow you to screw the heater into it BY HAND until the rubber gasket on the heater comes in contact with the bushing face. With this kind of fit, you can hand tighten the heater, then use a wrench to apply one more quarter turn, providing a liquid tight seal without any kind of teflon tape, pipe dope, or cranking down hard on the threads. In this manner, you can easily remove the element after every brew for cleaning. It only takes me about 30 seconds to completely dismantle my pump from the heater chamber, remove the two temperature probes and the heater element.