http://www.terrylove.com/forums/show...0&postcount=78 that made me do some more research in the Illinois plumbing code.
The Illinois plumbing code does not address the proper sizing of a tankless water heater directly like Florida does. But there are a couple parts that do help determine the proper size. For showers the maximum temperature is 115 degrees. For kitchen sinks the minimum temperature is 120 degrees. So with that in the code it addresses that the tankless system must be properly sized, or designed to be able to deliver these temperatures. With this information I contacted an Inspector and he informed me that he has failed installations that do not deliver 120 degree water to the kitchen sink while other fixtures are running. So now I need to write a couple letters to a few people explaining to them that they ether have to install the second tankless unit or ensure they are using low flow devices on their shower and sinks to ensure their single unit can meet the code properly. As for future installs I will insist on properly sizing the system for the demand to meet the code.