Question
I have a Hunter Pro-C Irrigation system, one of my sprinkler heads came off.  How do I replace it.
Thank you,
Stan

Answer
Thank for the question.
You will need to dig down to the fitting under the head and screw the sprinkler back on the fitting. Obviously, if the sprinkler is damaged you need a replacement. Examine the threads from the  fitting to be sure they are not distorted or cross threaded.
Teflon tape can be used on the threads but do not use glue or pipe sealant. It will make it a difficult job the next time to work on the sprinkler.
If you have further question, feel free to ask.