1. Check that the valve is fully open. 

After completing the grease injection operation, first check whether the ball diameter of the valve is parallel to the inner surface of the valve seat. If there is a difference, adjust the opening limit screw on the actuator to ensure that the valve is fully open. Otherwise, once the valve is installed, it will be impossible to determine whether the valve is in the fully open position. 
2. The valve is unable to inject lubricating grease. 
When performing the grease injection operation on the valve shaft (rod), the internal sealing pressure of the valve shaft (rod) must not exceed 20.68 MPa. If it exceeds this limit, one should check whether there is any malfunction with the grease injection gun and whether the outlet valve at the grease outlet of the grease injection gun is open. 
(2) If the valve grease gun is in good condition, check whether the grease injection port is blocked. That is, slowly unscrew the grease injection port and place it at the grease outlet hole of the grease gun. By injecting grease into the grease injection port, check whether grease can be injected. If no grease is injected, it indicates that the one-way valve inside the grease injection port is faulty and the grease injection port should be replaced. If the grease injection port can inject grease, check the one-way valve located downstream of the grease injection port in the grease injection hole (this one-way valve is usually installed in the grease injection holes of imported valves). Use special tools to unscrew it for inspection. If there are any blockages such as raw material tapes, remove them. For serious faults, replace it. 
If the grease cannot be injected yet, it is necessary to report to the professional engineer and the on-site supervisor, and the factory staff will handle it on-site. 
3. The grease injection holes do not dispense grease evenly. 
After the valve is filled with grease, sometimes the grease supply pipeline for the valve seat seal may get blocked, resulting in an uneven or no grease supply to the valve seat's grease injection hole. At this point, the valve can be closed by 15° to 25° from the fully open position - then inspect the grease injection hole of the valve seat and gently clear it with a soft object. Then, conduct the grease injection test again. It is particularly important to note that grease should not be injected during the valve ball's rolling process to avoid damaging the valve seat seal. Generally, each side of the ball valve's valve seat has 4 grease injection holes, and the grease supply from these holes is relatively uniform; while the grease supply from 2 of the injection holes is relatively uneven.