(1)The suction line is blocked or leaking air

(2)The suction height exceeds the allowable suction vacuum height

(3)Motor reversal

(4)Medium viscosity is too high

(1)Overhaul suction line

(2)Lower suction height

(3)Change motor steering

(4)Heat the medium

(1) the suction pipeline leakage

(2) the safety valve is not adjusted well or the working pressure is too large, so that the safety valve is open or closed

(1) the maintenance of the suction pipeline

(2) adjust the safety valve or reduce the working pressure

 (1) suction pipe blocked or leakage

(2) screw and pump sleeve wear

(3) safety valve spring is too loose or valve disc and valve seat contact is not strict

(4) motor speed is not enough 

(1) repair suction pipe (2) serious wear should be replaced parts (3)adjust the spring, grinding valve disc and valve seat

(4) repair or replace the motor

(1) the discharge pipeline blockage

(2) screw and pump sleeve serious friction (3) medium viscosity is too large

(1) stop the pump cleaning pipeline

(2) maintenance or replacement of relevant parts

(3) the medium temperature

(1) pump and motor different heart

(2) screw and pump sleeve different heart or clearance

(3) pump gas

(4) installation height is too large, pump cavitation

 (1) adjustment of concentricity

(2) maintenance adjustment

(3) maintenance of the suction line, eliminate the leakage parts

(4) reduce the installation height or reduce the speed

(1) severe friction in the pump

(2) mechanical seal oil return hole plugging

(3) oil temperature is too high

 (1) check the adjustment screw and pump sleeve

(2) dredge oil return hole

(3) appropriate to reduce oil temperature

(1) assembly position is wrong

(2) the sealing gland is not flattened

(3) the moving ring or static ring sealing ring damage

(1) to install the sealing gland as required

(2) adjust the sealing gland

(3) grinding the sealing surface or replacing the new part

(4) to replace the sealing ring