1.The main safety valve,  A49Y-Pw543.2V,  DN200, and the im-pulse safety valve A49Y-Pw543.2V, DN25,  should be installed togeth-er.   The distance between the outlet  pipe of the impulse safety valveand he inlet  pipe of the main safety valve should  be maintained as   relatively long the  distance between the  electric contact pres-sure meter and the inlet pipe of the main safety valve should be no less than 5 times of the diameter of the inlet  pipe, for fear that  the 
precision of the meter  and the impulse safety valve  may be affect-ed by the steam discharging process of  the main safety valve.
        2.Before the installation of the impulse safety valve, the pipeline  shall be cleaned first.
        3.The main safety valve  and the impulse safety  valve must be positioned vertically.
        4.The main safety valve shall be fastened upon the framework,which sustains the counter-reaction force  produced in the steamdischarging process of the main  safety valve. The exhaust pipe  of the main safety valve  shall be supported with  a special gallow lest  the force of  its weight and  action would be  directly apply to  both the main safety  valve and the flange that is  connectiong them. At  the lowest point  of the exhaust  pipe, water drainage shall be taken into consideration to avoid producing water hammer when the mainsafety valve is discharging steam.
         5.The impulse safety  valve and the  electromagnets shall be  Placed together on a special gallow The juncture of  the upper lever  of the valve and the electromagnets shall  be flexible, with no  phe-nomenon of seizure.  The impulse safety valve shall be installed in aplace with little dust,  dry air and convenient maintenance and de-bugging and where no  vibration occurs. Its ambient temperature shall not higher than 70 , and its relative humidity not more than 80%.
         6.To ensure the  agile working of the impulse safety valve, the  distance between the circular arc part  of the head of  the seat re-turning lever and the  end of the pressure bar of the  valve shall be   adjusted to the length of the actual travel of  the valve adding 1 mm(adjusted by the M10 fastening screw at  the top of  the cap).