How to de-winterize your trailer? *UPDATE*

If your water heater has a bypass, it will be empty. The procedures outlined above tell you how to reverse the bypass and fill the water heater. It's very important that the water heater is full before you turn it on or it will be damaged particularly if you run it on electric. To make absolutely sure it is full, pressurize the system either by connecting a hose to the water input or filling the tank and turning the pump on. Then standing aside lift the pressure relief valve at the top of your water heater. If the tank is full water will spray out. Return the pressure relief valve to the normal position and turn on the water heater. You should periodically activate the pressure relief valve anyway to make sure it is not clogged so this test actually accomplishes two things at once.