Thanks for the input everyone. I did not expect there to be any issues with installing it in aluminum, but since it was not reading anything, it was the first thougth I had. I have not had the chance to do any additional troubleshooting to see if the gauge is bad. It is a new guage, so you would hope it would not ship from the factory bad, but you never know. When I opened the box, there where no kinks and the tubing was nicely looped, so I am going to assume for the moment that the line is OK. I will keep you posted. Thanks again for the help.