When I plug the heater in it goes though a bootup which checks for any problems. Everything checks OK except the Obstruction light does not go out. The heater will run ok when I press the power button but the obstruction light stays on. How can I correct this problem. I would also like to know how to get the manual for this heater. I have tried to go to the page that is supposed to have the manual but it says that the page is not available. Any help would be appreciated. Thanks in advance. David Letson dnletson@gmail.com