Bleed 3 : To drain off liquid or gas, generally slowly, through a valve called a bleeder. To BLEED DOWN, or BLEED OFF, means to slowly release the pressure of a well or of pressurized equipment. (ITOGP)
The Mudblogger (Oilfield, Energy and Related Photographs), Oil Field Glossary, TX, USA 2014. http://mudblogger.com/oilfield-glossary/, (Oil - Amer) {777}