1. Before leaving factory, should adjust the discharge pressure of safety valve or relief valve to meet the customer required set pressure one by one. If the customer has requirement on the spring working pressure rating, normally adjust according to the lower limit value of this pressure rating.
2. Before mounting the safety valve or relief valve onto the protected equipment, the end user should adjust the discharge pressure once more on site, making sure the set pressure meets the customer’s requirements.
3. Within the spring working pressure range on the nameplate, by turning the adjusting screw on top of valve stem can change the spring compression, and then can adjust the safety valve (relief valve) discharge pressure.
4. Before turning the adjusting screw on top of valve to adjust the valve stem, should make the valve suction pressure reduce to less than 90% of valve discharge pressure, in order to prevent the valve disc is driven to turn when turning to adjust the valve stem, causing the sealing is damaged.
5. In order to make sure the discharge pressure to be accurate, should make the adjusting medium conditions, such as medium type and medium temperature to be similar with actual working medium conditions. When the medium type changes, especially when the medium changes from liquid to gas, the discharge pressure will change normally. When the medium temperature increases, the discharge pressure reduces normally. So, if adjust in normal temperature, and work in high temperature, the set pressure in normal temperature is a little higher than required discharge pressure.
6. Normally, the safety valve is applicable to fixed superimposed back pressure condition. When adjust the discharge pressure (now, the back pressure is the atmosphere), the set pressure should be required discharge pressure minus superimposed back pressure.