Finally got the new check valve. Took the old one out, the spring was laying loose in there and the small piece that was supposed to hold it is gone. Hopefully it flushed out of the water heater the first time I drained it at the campground. So basically what was happening was the piece that the spring would normally pull back toward the water heater to stop the backflow of cold water was free to flow with the water to the fitting that connects to the check valve. Where it would block the flow of water coming out of the water heater. $10 fix.