I have a water heater that get hot some of time but not enough to wash a sink of dishes. This just started a few days ago, I don't have the owners manual and can't find it online. Could someone help me?

You can use this site to talk with a Rheem tech. http://www.justanswer.com/sip/rheem/HVAC?r=ppc|ga|2|HI+%2D+HVAC|Rheem+%2D+2&JPKW=rheem%20model&JPDC=S&JPST=&JPAD=9527661298&JPAF=txt&JPCD=20110908&JPRC=1&JPMT=b&JPNW=g&JPOP=TransWillD1&gclid=CMvF2sTVkawCFQMUKgodwnz5nQ Heaters that act like yours can have a failed dip tube. Is it gas or electric?

Its gas

Put a garden hose on the drain spigot and flush some water into a bucket screening it through a white terry cloth towel. Tell what type of debris and colors you get. The water will be very hot so maybe a helper can stretch the towel over the bucket to make a screen.

I flushed it about a month ago

The problem wasn't present a month ago and you likely did not catch and inspect the debris. A dip tube can function almost perfectly one day and the next day give you cold water after a few moments.

I am about to go and do as your suggest, I will get back with you tomorrow, than you for your help.

It sounds like the dip tube is bad. Are you finding flakes of white plastic in your water or aerators. If you are it is the dip tube.

This seems to have solved the problem. I will have it checked out by a techinicain soon.

Flushing will not normally fix the issue you had.