Nozzle will have problem in following reasons:
We must take care when reassembling a nozzle. Internal components must be installed correctly or the nozzle will not perform as intended.
If the capacity is lower than expected then nozzle performance ,Ensure that there are no blockages in the piping system between the pump and the nozzles and that the pump has the capacity for the system. Pressures should be measure directly at the nozzle for the best accuracy.
Cross threading, over tightening, or stripping the hex are just some of the ways that a spray nozzle can become mechanically damaged. Spray nozzles in this condition will always need replacing.
Many chemical compounds have particles which are larger than the maximum free passage of the nozzle. Such compounds will result in clogging of the spray nozzle.
The Nozzle will degrades when the nozzle material have the chemical reactions with chemicals.Nozzles work in this situation will need to be replaced. If the wear occurred more quickly than expected then you should contact your chemical supplier or system designer to discuss alternative materials.