What are the reasons for the failure of automatic valve? How to deal with it?

The reasons for the failure of automatic valve include:
1) the valve is frozen by moisture and carbon dioxide, or stuck by other sundries. If there are a small amount of impurities on the sealing surface, it will cause the valve to close Unstrictly.
2) the fixed bolts of the automatic valve seat are not tightened evenly, and the air leakage from the gap of the gasket sometimes will damage the gasket, and the more leakage, the bigger.
3) the stem falls off. The reasons include: the fixed opening pin is broken, the nut is loose and falling off, and the spring is broken, etc.
4) the fixation bolts fall off, causing the whole automatic valve to fall off.
5) fracture of valve stem. The main reason is that the material of the valve stem is not good and the manufacture is defective. Or the spring is too hard, the valve stem is too stressed during the opening and closing process of the valve, etc.
6) The gap between the valve stem and the valve seat hole is too small, which will be stuck in low temperature.
When the automatic valve is found to be damaged, temporary stop should be adopted and the valve box should be heated separately. When the discharge temperature reaches about 10℃, it can be overhauled. If there is a shortage of automatic valve parts in the box, it should be blown out.