How to Open a Pressure Relief Valve
- 1). Locate the metal handle on the pressure relief valve on your water heater. Metal piping runs down from the valve.
- 2). Lift the handle up slowly and carefully. If the pressure is too high, water will begin funneling out of the pipe connected to the valve.
- 3). Leave the relief valve open until the excess water has drained through the piping and then bring the valve handle back down to its original position to close it.
Source...