These questions are directed to hvac1000.Can you explain superheat and subcooling to me in a way I can understand?Also,if someone accidentally added r-22 to a 410 system,what would be the effects and how long would it take to appear? Thank You

Lets do the easy question first.

R-22 and R-410A are totally incompatible when mixed together in the same system. The operating pressures are different along with glide slope,lubricant type,etc.
As far as what can happen is concerned naturally system damage comes to mind. Usually this will be centered around the compressor and its internal components.
If this has happened I recommend removal of the mixed refrigerant into a separate recovery tank which should be maintained for only that purpose and eventually sent off to a recycler to be destroyed. I also recommend that the tank be marked as a mixed tank with the mixed refrigerants clearly labeled on the tank. Mistakes do happen but corrections should be taken as soon as possible to prevent system damage.
Refrigerant normally does not come with a oil charge so the different style oil used with the R-410A should not have been introduced into the R-22 system BUT if the oil can be easily changed it is recommended to do so and if not then the system should be monitored for a period to make sure acid or other chemical breakdown does not take place. I will post answers to the other question a bit later.

I'' add this to munch on for superheat/subcooling:

Troubleshooting HVACR Systems Using Superheat and Subcooling - Service and Maintenance - Extra Edition - Air Conditioning, Heating & Refrigeration NEWS (http://www.achrnews.com/Articles/Service_and_Maintenance/dd8d6a73c50ec010VgnVCM100000f932a8c0____)

Fluke as a nice application note that distills the information even more.

Looks like KeepIt SimpleStupid has answered your question so I will defer any more of this question to him.