INSTALLLATION MANUAL: Unit is totally automatic but you must run water before plugging unit in for the first time  !!!!!!!!! If  you are going to use the unit  as an inline heater  (by removing the bottom part of the showerhead and attaching a garden hose).  Make sure the unit is  installed above of where the water comes out and  the open/close fixture ( spicket)is installed before the water inlet of the unit. THE "STALLION"ELECTRIC POINT OF USE INSTANT WATER HEATER: Shower head with integral water heater built in. Use for space restricted and portable applications such as boats, pool, camp facilities, hunt cabins  and RV. You can have a fully functional hot water shower system at a fraction of the normal equipment cost and installation time normally required. This self-contained shower system only uses electricity when operated.  The units are "on-demand" and "tankless" and therefore only needs a single water source to operate. The unit will operate properly with  a low  water  pressure of 2 PSI up to 150 PSI. Installation steps summary:  1) Remove your existing shower head .  2) Install the Stallion Heater unit 3) Run Water thru the showerhead, this will fill the water cavity where the resistance is lodged. 4) Make sure you have a 25 Amp circuit breaker to your existing breaker box and plug in the unit.  (outlet must be at least 6' from shower head)See circuit current requirements in table below. 5) The unit is  ready for use, just open the fixture and hot water will instantly come out, you can decrease temperature by increasing water flow.   PLUMBING INSTRUCTIONS: Open the pipe and let it run enough cold water to remove any sedimentation from the pipe The minimum water pressure supplied to the shower head shall be 1.5 PSI. This corresponds to about one meter                        If the plumbing does not have 1/2" thread, use an adapter. In  cases of LOW water pressure (1.5 Psi to 10 Psi)  the flow restrictor should  be removed (see figure 4). For pressure between 80 and 400 kPa (8 and 40 mca.) or municipal water source, it is necessary to keep the flow restrictor.(see figure 4)                              Install  the water connection and fill with water before making the electrical connection, this prevents burnout of the resistance heating element. Always repeat this operation should the product be removed. ELECTRIC INSTALLATION: Electrical Outlet Box must be at least 6' from shower head        SPECIAL ATTENTION!!!!!!!!!!!!!!!!!!